我收集的几个资料，没实践过，希望对你能有帮助：一个完整的上传bean
标题： 一个完整的上传bean
提交时间： 2001年7月5日
提交人： Sager
作者： popeyelin
程序/作者主页： //Title: Cnjsp's Project
//Version:
//Copyright: Copyright (c) 1999
//Author: Popeye
//Company: Cnjsp
//Description: It is for cnjsp package popeyelin;
import java.io.*;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest; public class transfer_multi {
public String[] sourcefile = new String[255];//源文件名
public String objectpath = "c:/";//目标文件目录
public String[] suffix = new String[255];//文件后缀名
public String[] objectfilename = new String[255];//目标文件名
public ServletInputStream sis = null;//输入流
public String[] description = new String[255];//描述状态
public long size = 100*1024;//限制大小
private int count = 0;//已传输文件数目
private byte[] b = new byte[4096];//字节流存放数组
private boolean successful = true; public void setSourcefile(HttpServletRequest request) throws java.io.IOException{
sis = request.getInputStream();
int a = 0;
int k = 0;
String s = "";
while((a = sis.readLine(b,0,b.length)) != -1){
s = new String(b,0,a);
if((k = s.indexOf("filename=")) != -1){
s = s.substring(k+10);
k = s.indexOf("\"");
s = s.substring(0,k);
sourcefile[count] = s;
k = s.lastIndexOf('.');
suffix[count] = s.substring(k+1);
System.out.println(suffix[count]);
if(canTransfer(count)) transferfile(count);
}
if(!successful) break;
}
}
public int getCount(){
return count;
}
public String[] getSourcefile(){
return sourcefile;
} public void setObjectpath(String objectpath){
this.objectpath = objectpath;
}
public String getObjectpath(){
return objectpath;
}
private boolean canTransfer(int i){
suffix[i] = suffix[i].toLowerCase();
//这个是我用来传图片的，各位可以把后缀名改掉或者不要这个条件
if(sourcefile[i].equals("")||(!suffix[i].equals("gif")&&!suffix[i].equals("jpg")&&!suffix[i].equals("jpeg"))) {description[i]="ERR suffix is wrong";return false;}
else return true;
}
private void transferfile(int i){
String x = Long.toString(new java.util.Date().getTime());
try{
objectfilename[i] = x+"."+suffix[i];
FileOutputStream out = new FileOutputStream(objectpath+objectfilename[i]);
int a = 0;
int k = 0;
long hastransfered = 0;//标示已经传输的字节数
String s = "";
while((a = sis.readLine(b,0,b.length)) != -1){
s = new String(b,0,a);
if((k = s.indexOf("Content-Type:")) != -1) break;
}
sis.readLine(b,0,b.length);
while((a = sis.readLine(b,0,b.length)) != -1){
s = new String(b,0,a);
if((b[0]==45)&&(b[1]==45)&&(b[2]==45)&&(b[3]==45)&&(b[4]==45)) break;
out.write(b,0,a);
hastransfered+=a;
if(hastransfered>=size){
description[count] = "ERR The file "+sourcefile[count]+" is too large to transfer. The whole process is interrupted.";
successful = false;
break;
}
}
if(successful) description[count] = "Right The file "+sourcefile[count]+" has been transfered successfully.";
++count;
out.close();
if(!successful){
sis.close();
File tmp = new File(objectpath+objectfilename[count-1]);
tmp.delete();
}
}
catch(IOException ioe){
description[i]=ioe.toString();
} } public transfer_multi(){
//可以在构建器里面构建服务器上传目录，也可以在javabean调用的时候自己构建
setObjectpath("/home/www/jspvhost4/web/popeyelin/images/");
}
}
————————————————————————————————从数据库中读取并生成图片的Servlet [关键字: Java & JSP 人气:73]
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大体思路
1）创建ServletOutputStream对象out,用于以字节流的方式输出图像
2）查询数据库，用getBinaryStream方法返回InputStream对象in
3）创建byte数组用作缓冲，将in读入buf[],再由out输出
注：下面的例程中数据库连接用了ConnectionPool,以及参数的获得进行了预处理
package net.seasky.music;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.sql.*;
import net.seasky.util.*;
import net.seasky.database.DbConnectionManager;
public class CoverServlet extends HttpServlet {
private static final String CONTENT_TYPE = "image/gif";
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
public void doGet(HttpServletRequest request, HttpServletResponse response
) throws ServletException, IOException {
response.setContentType(CONTENT_TYPE);
int albumID;
ServletOutputStream out = response.getOutputStream();
try {
albumID = ParamManager.getIntParameter(request,"albumID",0);
}
catch (Exception e) {
response.sendRedirect("../ErroePage.jsp");
return;
}
try {
InputStream in=this.getCover(albumID);
int len;
byte buf[]=new byte[1024];
while ((len=in.read(buf,0,1024))!=-1) {
out.write(buf,0,len);
}
}
catch (IOException ioe) {
ioe.printStackTrace() ;
}
}
private InputStream getCover(int albumID) {
InputStream in=null;
Connection cn = null;
PreparedStatement pst = null;
try {
cn=DbConnectionManager.getConnection();
cn.setCatalog("music");
pst=cn.prepareStatement("SELECT img FROM cover where ID =?");
pst.setInt(1,albumID);
ResultSet rs=pst.executeQuery();
rs.next() ;
in=rs.getBinaryStream("img");
}
catch (SQLException sqle) {
System.err.println("Error in CoverServlet : getCover()-" + sqle);
sqle.printStackTrace() ;
}
finally {
try {
pst.close() ; cn.close() ;
}
catch (Exception e) {
e.printStackTrace();
}
}
return in;
}
public void destroy() {
}
} ——————————————————————————————如何在Web页上实现文件上传 关键字：java 人气值:
529 文档分类:
Java 贴文时间
2001-5-15 16:44:13 得票数:
35 给贴子投票
投票 收藏者:wxyxl
出处:
public class UploadServlet extends HttpServlet
{
//default maximum allowable file size is 100k
static final int MAX_SIZE = 102400;
//instance variables to store root and success message
String rootPath, successMessage;
/**
* init method is called when servlet is initialized.
*/
public void init(ServletConfig config) throws ServletException
{
super.init(config);
//get path in which to save file
rootPath = config.getInitParameter("RootPath");
if (rootPath == null)
{
rootPath = "/";
}
/*Get message to show when upload is complete. Used only if
a success redirect page is not supplied.*/
successMessage = config.getInitParameter("SuccessMessage");
if (successMessage == null)
{
successMessage = "File upload complete!";
}
}
/**
* doPost reads the uploaded data from the request and writes
* it to a file.
*/
public void doPost(HttpServletRequest request,
HttpServletResponse response)
{
ServletOutputStream out=null;
DataInputStream in=null;
FileOutputStream fileOut=null;
try
{
/*set content type of response and get handle to output
stream in case we are unable to redirect client*/
response.setContentType("text/plain");
out = response.getOutputStream();
}
catch (IOException e)
{
//print error message to standard out
System.out.println("Error getting output stream.");
System.out.println("Error description: " + e);
return;
}
try
{
//get content type of client request
String contentType = request.getContentType();
//make sure content type is multipart/form-data
if(contentType != null && contentType.indexOf(
"multipart/form-data") != -1)
{
//open input stream from client to capture upload file
in = new DataInputStream(request.getInputStream());
//get length of content data
int formDataLength = request.getContentLength();
//allocate a byte array to store content data
byte dataBytes[] = new byte[formDataLength];
//read file into byte array
int bytesRead = 0;
int totalBytesRead = 0;
int sizeCheck = 0;
while (totalBytesRead < formDataLength)
{
//check for maximum file size violation
sizeCheck = totalBytesRead + in.available();
if (sizeCheck > MAX_SIZE)
{
out.println("Sorry, file is too large to upload.");
return;
}
bytesRead = in.read(dataBytes, totalBytesRead,
formDataLength);
totalBytesRead += bytesRead;
}
//create string from byte array for easy manipulation
String file = new String(dataBytes);
//since byte array is stored in string, release memory
dataBytes = null;
/*get boundary value (boundary is a unique string that
separates content data)*/
int lastIndex = contentType.lastIndexOf("=");
String boundary = contentType.substring(lastIndex+1,
contentType.length());
//get Directory web variable from request
String directory="";
if (file.indexOf("name=\"Directory\"") > 0)
{
directory = file.substring(
file.indexOf("name=\"Directory\""));
//remove carriage return
directory = directory.substring(
directory.indexOf("\n")+1);
//remove carriage return
directory = directory.substring(
directory.indexOf("\n")+1);
//get Directory
directory = directory.substring(0,
directory.indexOf("\n")-1);
/*make sure user didn't select a directory higher in
the directory tree*/
if (directory.indexOf("..") > 0)
{
out.println("Security Error: You can't upload " +
"to a directory higher in the directory tree.");
return;
}
}
//get SuccessPage web variable from request
String successPage="";
if (file.indexOf("name=\"SuccessPage\"") > 0)
{
successPage = file.substring(
file.indexOf("name=\"SuccessPage\""));
//remove carriage return
successPage = successPage.substring(
successPage.indexOf("\n")+1);
//remove carriage return
successPage = successPage.substring(
successPage.indexOf("\n")+1);
//get success page
successPage = successPage.substring(0,
successPage.indexOf("\n")-1);
}
//get OverWrite flag web variable from request
String overWrite;
if (file.indexOf("name=\"OverWrite\"") > 0)
{
overWrite = file.substring(
file.indexOf("name=\"OverWrite\""));
//remove carriage return
overWrite = overWrite.substring(
overWrite.indexOf("\n")+1);
//remove carriage return
overWrite = overWrite.substring(
overWrite.indexOf("\n")+1);
//get overwrite flag
overWrite = overWrite.substring(0,
overWrite.indexOf("\n")-1);
}
else
{
overWrite = "false";
}
//get OverWritePage web variable from request
String overWritePage="";
if (file.indexOf("name=\"OverWritePage\"") > 0)
{
overWritePage = file.substring(
file.indexOf("name=\"OverWritePage\""));
//remove carriage return
overWritePage = overWritePage.substring(
overWritePage.indexOf("\n")+1);
//remove carriage return
overWritePage = overWritePage.substring(
overWritePage.indexOf("\n")+1);
//get overwrite page
overWritePage = overWritePage.substring(0,
overWritePage.indexOf("\n")-1);
}
//get filename of upload file
String saveFile = file.substring(
file.indexOf("filename=\"")+10);
saveFile = saveFile.substring(0,
saveFile.indexOf("\n"));
saveFile = saveFile.substring(
saveFile.lastIndexOf("\\")+1,
saveFile.indexOf("\""));
/*remove boundary ers and other multipart/form-data
tags from beginning of upload file section*/
int pos; //position in upload file
//find position of upload file section of request
pos = file.indexOf("filename=\"");
//find position of content-disposition line
pos = file.indexOf("\n",pos)+1;
//find position of content-type line
pos = file.indexOf("\n",pos)+1;
//find position of blank line
pos = file.indexOf("\n",pos)+1;
/*find the location of the next boundary er
(ing the end of the upload file data)*/
int boundaryLocation = file.indexOf(boundary,pos)-4;
//upload file lies between pos and boundaryLocation
file = file.substring(pos,boundaryLocation);
//build the full path of the upload file
String fileName = new String(rootPath + directory +
saveFile);
//create File object to check for existence of file
File checkFile = new File(fileName);
if (checkFile.exists())
{
/*file exists, if OverWrite flag is off, give
message and abort*/
if (!overWrite.toLowerCase().equals("true"))
{
if (overWritePage.equals(""))
{
/*OverWrite HTML page URL not received, respond
with generic message*/
out.println("Sorry, file already exists.");
}
else
{
//redirect client to OverWrite HTML page
response.sendRedirect(overWritePage);
}
return;
}
}
/*create File object to check for existence of
Directory*/
File fileDir = new File(rootPath + directory);
if (!fileDir.exists())
{
//Directory doesn't exist, create it
fileDir.mkdirs();
}
//instantiate file output stream
fileOut = new FileOutputStream(fileName);
//write the string to the file as a byte array
fileOut.write(file.getBytes(),0,file.length());
if (successPage.equals(""))
{
/*success HTML page URL not received, respond with
generic success message*/
out.println(successMessage);
out.println("File written to: " + fileName);
}
else
{
//redirect client to success HTML page
response.sendRedirect(successPage);
}
}
else //request is not multipart/form-data
{
//send error message to client
out.println("Request not multipart/form-data.");
}
}
catch(Exception e)
{
try
{
//print error message to standard out
System.out.println("Error in doPost: " + e);
//send error message to client
out.println("An unexpected error has occurred.");
out.println("Error description: " + e);
}
catch (Exception f) {}
}
finally
{
try
{
fileOut.close(); //close file output stream
}
catch (Exception f) {}
try
{
in.close(); //close input stream from client
}
catch (Exception f) {}
try
{
out.close(); //close output stream to client
}
catch (Exception f) {}
}
}
}————————————————————————————————用Java实现断点续传(HTTP)
内容：
(一)断点续传的原理
(二)Java实现断点续传的关键几点
(三)断点续传内核的实现
关于作者
钟华 ([email protected])
2001 年 5 月(一)断点续传的原理
其实断点续传的原理很简单，就是在Http的请求上和一般的下载有所不同而已。
打个比方，浏览器请求服务器上的一个文时，所发出的请求如下：
假设服务器域名为wwww.sjtu.edu.cn，文件名为down.zip。
GET /down.zip HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-
excel, application/msword, application/vnd.ms-powerpoint, */*
Accept-Language: zh-cn
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)
Connection: Keep-Alive
服务器收到请求后，按要求寻找请求的文件，提取文件的信息，然后返回给浏览器，返回信息如下：
200
Content-Length=106786028
Accept-Ranges=bytes
Date=Mon, 30 Apr 2001 12:56:11 GMT
ETag=W/"02ca57e173c11:95b"
Content-Type=application/octet-stream
Server=Microsoft-IIS/5.0
Last-Modified=Mon, 30 Apr 2001 12:56:11 GMT
所谓断点续传，也就是要从文件已经下载的地方开始继续下载。所以在客户端浏览器传给
Web服务器的时候要多加一条信息--从哪里开始。
下面是用自己编的一个"浏览器"来传递请求信息给Web服务器，要求从2000070字节开始。
GET /down.zip HTTP/1.0
User-Agent: NetFox
RANGE: bytes=2000070-
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
仔细看一下就会发现多了一行RANGE: bytes=2000070-
这一行的意思就是告诉服务器down.zip这个文件从2000070字节开始传，前面的字节不用传了。
服务器收到这个请求以后，返回的信息如下：
206
Content-Length=106786028
Content-Range=bytes 2000070-106786027/106786028
Date=Mon, 30 Apr 2001 12:55:20 GMT
ETag=W/"02ca57e173c11:95b"
Content-Type=application/octet-stream
Server=Microsoft-IIS/5.0
Last-Modified=Mon, 30 Apr 2001 12:55:20 GMT
和前面服务器返回的信息比较一下，就会发现增加了一行：
Content-Range=bytes 2000070-106786027/106786028
返回的代码也改为206了，而不再是200了。
知道了以上原理，就可以进行断点续传的编程了。
(二)Java实现断点续传的关键几点
(1)用什么方法实现提交RANGE: bytes=2000070-。
当然用最原始的Socket是肯定能完成的，不过那样太费事了，其实Java的net包中提供了这种功能。代码如下：
URL url = new URL("http://www.sjtu.edu.cn/down.zip");
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection
();
//设置User-Agent
httpConnection.setRequestProperty("User-Agent","NetFox");
//设置断点续传的开始位置
httpConnection.setRequestProperty("RANGE","bytes=2000070");
//获得输入流
InputStream input = httpConnection.getInputStream();
从输入流中取出的字节流就是down.zip文件从2000070开始的字节流。
大家看，其实断点续传用Java实现起来还是很简单的吧。
接下来要做的事就是怎么保存获得的流到文件中去了。
保存文件采用的方法。
我采用的是IO包中的RandAccessFile类。
操作相当简单，假设从2000070处开始保存文件，代码如下：
RandomAccess oSavedFile = new RandomAccessFile("down.zip","rw");
long nPos = 2000070;
//定位文件指针到nPos位置
oSavedFile.seek(nPos);
byte[] b = new byte[1024];
int nRead;
//从输入流中读入字节流，然后写到文件中
while((nRead=input.read(b,0,1024)) > 0)
{
oSavedFile.write(b,0,nRead);
}怎么样，也很简单吧。
接下来要做的就是整合成一个完整的程序了。包括一系列的线程控制等等。(三)断点续传内核的实现
主要用了6个类，包括一个测试类。
SiteFileFetch.java负责整个文件的抓取，控制内部线程(FileSplitterFetch类)。
FileSplitterFetch.java负责部分文件的抓取。
FileAccess.java负责文件的存储。
SiteInfoBean.java要抓取的文件的信息，如文件保存的目录，名字，抓取文件的URL等。
Utility.java工具类，放一些简单的方法。
TestMethod.java测试类。
下面是源程序：
/*
**SiteFileFetch.java
*/
package NetFox;
import java.io.*;
import java.net.*;
public class SiteFileFetch extends Thread {
SiteInfoBean siteInfoBean = null; //文件信息Bean
long[] nStartPos; //开始位置
long[] nEndPos; //结束位置
FileSplitterFetch[] fileSplitterFetch; //子线程对象
long nFileLength; //文件长度
boolean bFirst = true; //是否第一次取文件
boolean bStop = false; //停止标志
File tmpFile; //文件下载的临时信息
DataOutputStream output; //输出到文件的输出流
public SiteFileFetch(SiteInfoBean bean) throws IOException
{
siteInfoBean = bean;
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
if(tmpFile.exists ())
{
bFirst = false;
read_nPos();
}
else
{
nStartPos = new long[bean.getNSplitter()];
nEndPos = new long[bean.getNSplitter()];
}}
public void run()
{
//获得文件长度
//分割文件
//实例FileSplitterFetch
//启动FileSplitterFetch线程
//等待子线程返回
try{
if(bFirst)
{
nFileLength = getFileSize();
if(nFileLength == -1)
{
System.err.println("File Length is not known!");
}
else if(nFileLength == -2)
{
System.err.println("File is not access!");
}
else
{
for(int i=0;i<nStartPos.length;i++)
{
nStartPos[i] = (long)(i*(nFileLength/nStartPos.length));
}
for(int i=0;i<nEndPos.length-1;i++)
{
nEndPos[i] = nStartPos[i+1];
}
nEndPos[nEndPos.length-1] = nFileLength;
}
}
//启动子线程
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
for(int i=0;i<nStartPos.length;i++)
{
fileSplitterFetch[i] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
nStartPos[i],nEndPos[i],i);
Utility.log("Thread " + i + " , nStartPos = " + nStartPos[i] + ", nEndPos = " + nEndPos[i]);
fileSplitterFetch[i].start();
}
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
nEndPos = " + nFileLength);
// fileSplitterFetch[nPos.length-1].start();
//等待子线程结束
//int count = 0;
//是否结束while循环
boolean breakWhile = false;
while(!bStop)
{
write_nPos();
Utility.sleep(500);
breakWhile = true;
for(int i=0;i<nStartPos.length;i++)
{
if(!fileSplitterFetch[i].bDownOver)
{
breakWhile = false;
break;
}
}
if(breakWhile)
break;
//count++;
//if(count>4)
// siteStop();
}
System.err.println("文件下载结束！");
}
catch(Exception e){e.printStackTrace ();}
}
//获得文件长度
public long getFileSize()
{
int nFileLength = -1;
try{
URL url = new URL(siteInfoBean.getSSiteURL());
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
httpConnection.setRequestProperty("User-Agent","NetFox");
int responseCode=httpConnection.getResponseCode();
if(responseCode>=400)
{
processErrorCode(responseCode);
return -2; //-2 represent access is error
}
String sHeader;
for(int i=1;;i++)
{
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
//Utility.log(in.readLine());
sHeader=httpConnection.getHeaderFieldKey(i);
if(sHeader!=null)
{
if(sHeader.equals("Content-Length"))
{
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
break;
}
}
else
break;
}
}
catch(IOException e){e.printStackTrace ();}
catch(Exception e){e.printStackTrace ();}
Utility.log(nFileLength);
return nFileLength;
}
//保存下载信息（文件指针位置）
private void write_nPos()
{
try{
output = new DataOutputStream(new FileOutputStream(tmpFile));
output.writeInt(nStartPos.length);
for(int i=0;i<nStartPos.length;i++)
{
// output.writeLong(nPos[i]);
output.writeLong(fileSplitterFetch[i].nStartPos);
output.writeLong(fileSplitterFetch[i].nEndPos);
}
output.close();
}
catch(IOException e){e.printStackTrace ();}
catch(Exception e){e.printStackTrace ();}
}
//读取保存的下载信息（文件指针位置）
private void read_nPos()
{
try{
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
int nCount = input.readInt();
nStartPos = new long[nCount];
nEndPos = new long[nCount];
for(int i=0;i<nStartPos.length;i++)
{
nStartPos[i] = input.readLong();
nEndPos[i] = input.readLong();
}
input.close();
}
catch(IOException e){e.printStackTrace ();}
catch(Exception e){e.printStackTrace ();}
}
private void processErrorCode(int nErrorCode)
{
System.err.println("Error Code : " + nErrorCode);
}
//停止文件下载
public void siteStop()
{
bStop = true;
for(int i=0;i<nStartPos.length;i++)
fileSplitterFetch[i].splitterStop();
}
}
/*
**FileSplitterFetch.java
*/
package NetFox;
import java.io.*;
import java.net.*;
public class FileSplitterFetch extends Thread {
String sURL; //File URL
long nStartPos; //File Snippet Start Position
long nEndPos; //File Snippet End Position
int nThreadID; //Thread's ID
boolean bDownOver = false; //Downing is over
boolean bStop = false; //Stop identical
FileAccessI fileAccessI = null; //File Access interface
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
{
this.sURL = sURL;
this.nStartPos = nStart;
this.nEndPos = nEnd;
nThreadID = id;
fileAccessI = new FileAccessI(sName,nStartPos);
}
public void run()
{
while(nStartPos < nEndPos && !bStop)
{
try{
URL url = new URL(sURL);
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
httpConnection.setRequestProperty("User-Agent","NetFox");
String sProperty = "bytes="+nStartPos+"-";
httpConnection.setRequestProperty("RANGE",sProperty);
Utility.log(sProperty);
InputStream input = httpConnection.getInputStream();
//logResponseHead(httpConnection);
byte[] b = new byte[1024];
int nRead;
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
{
nStartPos += fileAccessI.write(b,0,nRead);
//if(nThreadID == 1)
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
}
Utility.log("Thread " + nThreadID + " is over!");
bDownOver = true;
//nPos = fileAccessI.write (b,0,nRead);
}
catch(Exception e){e.printStackTrace ();}
}
}
//打印回应的头信息
public void logResponseHead(HttpURLConnection con)
{
for(int i=1;;i++)
{
String header=con.getHeaderFieldKey(i);
if(header!=null)
//responseHeaders.put(header,httpConnection.getHeaderField(header));
Utility.log(header+" : "+con.getHeaderField(header));
else
break;
}
}
public void splitterStop()
{
bStop = true;
}
}
/*
**FileAccess.java
*/
package NetFox;
import java.io.*;
public class FileAccessI implements Serializable{
RandomAccessFile oSavedFile;
long nPos;
public FileAccessI() throws IOException
{
this("",0);
}
public FileAccessI(String sName,long nPos) throws IOException
{
oSavedFile = new RandomAccessFile(sName,"rw");
this.nPos = nPos;
oSavedFile.seek(nPos);
}
public synchronized int write(byte[] b,int nStart,int nLen)
{
int n = -1;
try{
oSavedFile.write(b,nStart,nLen);
n = nLen;
}
catch(IOException e)
{
e.printStackTrace ();
}
return n;
}
}
/*
**SiteInfoBean.java
*/
package NetFox;
public class SiteInfoBean {
private String sSiteURL; //Site's URL
private String sFilePath; //Saved File's Path
private String sFileName; //Saved File's Name
private int nSplitter; //Count of Splited Downloading File
public SiteInfoBean()
{
//default value of nSplitter is 5
this("","","",5);
}
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
{
sSiteURL= sURL;
sFilePath = sPath;
sFileName = sName;
this.nSplitter = nSpiltter;
}
public String getSSiteURL()
{
return sSiteURL;
}
public void setSSiteURL(String value)
{
sSiteURL = value;
}
public String getSFilePath()
{
return sFilePath;
}
public void setSFilePath(String value)
{
sFilePath = value;
}
public String getSFileName()
{
return sFileName;
}
public void setSFileName(String value)
{
sFileName = value;
}
public int getNSplitter()
{
return nSplitter;
}
public void setNSplitter(int nCount)
{
nSplitter = nCount;
}
}
/*
**Utility.java
*/
package NetFox;
public class Utility {
public Utility()
{
}
public static void sleep(int nSecond)
{
try{
Thread.sleep(nSecond);
}
catch(Exception e)
{
e.printStackTrace ();
}
}
public static void log(String sMsg)
{
System.err.println(sMsg);
}
public static void log(int sMsg)
{
System.err.println(sMsg);
}
}
/*
**TestMethod.java
*/
package NetFox;
public class TestMethod {
public TestMethod()
{ ///xx/weblogic60b2_win.exe
try{
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
SiteFileFetch fileFetch = new SiteFileFetch(bean);
fileFetch.start();
}
catch(Exception e){e.printStackTrace ();}
}
public static void main(String[] args)
{
new TestMethod();
}
}
————————————————————————————————jsp文件操作之读取篇
2000-12-19 动网先锋 2000-11-28· coolknight·yesky 文件操作是网站编程的重要内容之一，asp关于文件操作讨论的已经很多了，让我们来看看jsp中是如何实现的。
这里用到了两个文件，一个jsp文件一个javabean文件，通过jsp中调用javabean可以轻松读取文本文件，注意请放置一个文本文件afile.txt到web根目录的test目录下，javabean文件编译后将class文件放到对应的class目录下(tomcat环境)。
Read.jsp<html>
<head>
<title>读取一个文件</title>
</head>
<body bgcolor="#000000">
<%--调用javabean --%>
<jsp:useBean id="reader" class="DelimitedDataFile" scope="request">
<jsp:setProperty name="reader" property="path" value="/test/afile.txt" />
</jsp:useBean><h3>文件内容:</h3><p><% int count = 0; %>
<% while (reader.nextRecord() != -1) { %>
<% count++; %>
<b>第<% out.print(count); %>行:</b>
<% out.print(reader.returnRecord()); %><br>
<% } %>
</p>
</body>
</html>
//DelimitedDataFile.java bean文件源代码
//导入java包
import java.io.*;
import java.util.StringTokenizer;public class DelimitedDataFile
{private String currentRecord = null;
private BufferedReader file;
private String path;
private StringTokenizer token;
//创建文件对象
public DelimitedDataFile()
{
file = new BufferedReader(new InputStreamReader(System.in),1);
}
public DelimitedDataFile(String filePath) throws FileNotFoundException
{
path = filePath;
file = new BufferedReader(new FileReader(path));
}
//设置文件路径
public void setPath(String filePath)
{
path = filePath;
try {
file = new BufferedReader(new
FileReader(path));
} catch (FileNotFoundException e) {
System.out.println("file not found");
}
}
//得到文件路径
public String getPath() {
return path;
}
//关闭文件
public void fileClose() throws IOException
{
file.close();
}
//读取下一行记录，若没有则返回-1
public int nextRecord()
{
int returnInt = -1;
try
{
currentRecord = file.readLine();
}
catch (IOException e)
{
System.out.println("readLine problem, terminating.");
}
if (currentRecord == null)
returnInt = -1;
else
{
token = new StringTokenizer(currentRecord);
returnInt = token.countTokens();
}
return returnInt;
} //以字符串的形式返回整个记录
public String returnRecord()
{return currentRecord;
}
}
标题： 一个完整的上传bean
提交时间： 2001年7月5日
提交人： Sager
作者： popeyelin
程序/作者主页： //Title: Cnjsp's Project
//Version:
//Copyright: Copyright (c) 1999
//Author: Popeye
//Company: Cnjsp
//Description: It is for cnjsp package popeyelin;
import java.io.*;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest; public class transfer_multi {
public String[] sourcefile = new String[255];//源文件名
public String objectpath = "c:/";//目标文件目录
public String[] suffix = new String[255];//文件后缀名
public String[] objectfilename = new String[255];//目标文件名
public ServletInputStream sis = null;//输入流
public String[] description = new String[255];//描述状态
public long size = 100*1024;//限制大小
private int count = 0;//已传输文件数目
private byte[] b = new byte[4096];//字节流存放数组
private boolean successful = true; public void setSourcefile(HttpServletRequest request) throws java.io.IOException{
sis = request.getInputStream();
int a = 0;
int k = 0;
String s = "";
while((a = sis.readLine(b,0,b.length)) != -1){
s = new String(b,0,a);
if((k = s.indexOf("filename=")) != -1){
s = s.substring(k+10);
k = s.indexOf("\"");
s = s.substring(0,k);
sourcefile[count] = s;
k = s.lastIndexOf('.');
suffix[count] = s.substring(k+1);
System.out.println(suffix[count]);
if(canTransfer(count)) transferfile(count);
}
if(!successful) break;
}
}
public int getCount(){
return count;
}
public String[] getSourcefile(){
return sourcefile;
} public void setObjectpath(String objectpath){
this.objectpath = objectpath;
}
public String getObjectpath(){
return objectpath;
}
private boolean canTransfer(int i){
suffix[i] = suffix[i].toLowerCase();
//这个是我用来传图片的，各位可以把后缀名改掉或者不要这个条件
if(sourcefile[i].equals("")||(!suffix[i].equals("gif")&&!suffix[i].equals("jpg")&&!suffix[i].equals("jpeg"))) {description[i]="ERR suffix is wrong";return false;}
else return true;
}
private void transferfile(int i){
String x = Long.toString(new java.util.Date().getTime());
try{
objectfilename[i] = x+"."+suffix[i];
FileOutputStream out = new FileOutputStream(objectpath+objectfilename[i]);
int a = 0;
int k = 0;
long hastransfered = 0;//标示已经传输的字节数
String s = "";
while((a = sis.readLine(b,0,b.length)) != -1){
s = new String(b,0,a);
if((k = s.indexOf("Content-Type:")) != -1) break;
}
sis.readLine(b,0,b.length);
while((a = sis.readLine(b,0,b.length)) != -1){
s = new String(b,0,a);
if((b[0]==45)&&(b[1]==45)&&(b[2]==45)&&(b[3]==45)&&(b[4]==45)) break;
out.write(b,0,a);
hastransfered+=a;
if(hastransfered>=size){
description[count] = "ERR The file "+sourcefile[count]+" is too large to transfer. The whole process is interrupted.";
successful = false;
break;
}
}
if(successful) description[count] = "Right The file "+sourcefile[count]+" has been transfered successfully.";
++count;
out.close();
if(!successful){
sis.close();
File tmp = new File(objectpath+objectfilename[count-1]);
tmp.delete();
}
}
catch(IOException ioe){
description[i]=ioe.toString();
} } public transfer_multi(){
//可以在构建器里面构建服务器上传目录，也可以在javabean调用的时候自己构建
setObjectpath("/home/www/jspvhost4/web/popeyelin/images/");
}
}
————————————————————————————————从数据库中读取并生成图片的Servlet [关键字: Java & JSP 人气:73]
网友对本文的评论共有0篇 [查看/发表评论] [专业IT技术论坛]
大体思路
1）创建ServletOutputStream对象out,用于以字节流的方式输出图像
2）查询数据库，用getBinaryStream方法返回InputStream对象in
3）创建byte数组用作缓冲，将in读入buf[],再由out输出
注：下面的例程中数据库连接用了ConnectionPool,以及参数的获得进行了预处理
package net.seasky.music;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.sql.*;
import net.seasky.util.*;
import net.seasky.database.DbConnectionManager;
public class CoverServlet extends HttpServlet {
private static final String CONTENT_TYPE = "image/gif";
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
public void doGet(HttpServletRequest request, HttpServletResponse response
) throws ServletException, IOException {
response.setContentType(CONTENT_TYPE);
int albumID;
ServletOutputStream out = response.getOutputStream();
try {
albumID = ParamManager.getIntParameter(request,"albumID",0);
}
catch (Exception e) {
response.sendRedirect("../ErroePage.jsp");
return;
}
try {
InputStream in=this.getCover(albumID);
int len;
byte buf[]=new byte[1024];
while ((len=in.read(buf,0,1024))!=-1) {
out.write(buf,0,len);
}
}
catch (IOException ioe) {
ioe.printStackTrace() ;
}
}
private InputStream getCover(int albumID) {
InputStream in=null;
Connection cn = null;
PreparedStatement pst = null;
try {
cn=DbConnectionManager.getConnection();
cn.setCatalog("music");
pst=cn.prepareStatement("SELECT img FROM cover where ID =?");
pst.setInt(1,albumID);
ResultSet rs=pst.executeQuery();
rs.next() ;
in=rs.getBinaryStream("img");
}
catch (SQLException sqle) {
System.err.println("Error in CoverServlet : getCover()-" + sqle);
sqle.printStackTrace() ;
}
finally {
try {
pst.close() ; cn.close() ;
}
catch (Exception e) {
e.printStackTrace();
}
}
return in;
}
public void destroy() {
}
} ——————————————————————————————如何在Web页上实现文件上传 关键字：java 人气值:
529 文档分类:
Java 贴文时间
2001-5-15 16:44:13 得票数:
35 给贴子投票
投票 收藏者:wxyxl
出处:
public class UploadServlet extends HttpServlet
{
//default maximum allowable file size is 100k
static final int MAX_SIZE = 102400;
//instance variables to store root and success message
String rootPath, successMessage;
/**
* init method is called when servlet is initialized.
*/
public void init(ServletConfig config) throws ServletException
{
super.init(config);
//get path in which to save file
rootPath = config.getInitParameter("RootPath");
if (rootPath == null)
{
rootPath = "/";
}
/*Get message to show when upload is complete. Used only if
a success redirect page is not supplied.*/
successMessage = config.getInitParameter("SuccessMessage");
if (successMessage == null)
{
successMessage = "File upload complete!";
}
}
/**
* doPost reads the uploaded data from the request and writes
* it to a file.
*/
public void doPost(HttpServletRequest request,
HttpServletResponse response)
{
ServletOutputStream out=null;
DataInputStream in=null;
FileOutputStream fileOut=null;
try
{
/*set content type of response and get handle to output
stream in case we are unable to redirect client*/
response.setContentType("text/plain");
out = response.getOutputStream();
}
catch (IOException e)
{
//print error message to standard out
System.out.println("Error getting output stream.");
System.out.println("Error description: " + e);
return;
}
try
{
//get content type of client request
String contentType = request.getContentType();
//make sure content type is multipart/form-data
if(contentType != null && contentType.indexOf(
"multipart/form-data") != -1)
{
//open input stream from client to capture upload file
in = new DataInputStream(request.getInputStream());
//get length of content data
int formDataLength = request.getContentLength();
//allocate a byte array to store content data
byte dataBytes[] = new byte[formDataLength];
//read file into byte array
int bytesRead = 0;
int totalBytesRead = 0;
int sizeCheck = 0;
while (totalBytesRead < formDataLength)
{
//check for maximum file size violation
sizeCheck = totalBytesRead + in.available();
if (sizeCheck > MAX_SIZE)
{
out.println("Sorry, file is too large to upload.");
return;
}
bytesRead = in.read(dataBytes, totalBytesRead,
formDataLength);
totalBytesRead += bytesRead;
}
//create string from byte array for easy manipulation
String file = new String(dataBytes);
//since byte array is stored in string, release memory
dataBytes = null;
/*get boundary value (boundary is a unique string that
separates content data)*/
int lastIndex = contentType.lastIndexOf("=");
String boundary = contentType.substring(lastIndex+1,
contentType.length());
//get Directory web variable from request
String directory="";
if (file.indexOf("name=\"Directory\"") > 0)
{
directory = file.substring(
file.indexOf("name=\"Directory\""));
//remove carriage return
directory = directory.substring(
directory.indexOf("\n")+1);
//remove carriage return
directory = directory.substring(
directory.indexOf("\n")+1);
//get Directory
directory = directory.substring(0,
directory.indexOf("\n")-1);
/*make sure user didn't select a directory higher in
the directory tree*/
if (directory.indexOf("..") > 0)
{
out.println("Security Error: You can't upload " +
"to a directory higher in the directory tree.");
return;
}
}
//get SuccessPage web variable from request
String successPage="";
if (file.indexOf("name=\"SuccessPage\"") > 0)
{
successPage = file.substring(
file.indexOf("name=\"SuccessPage\""));
//remove carriage return
successPage = successPage.substring(
successPage.indexOf("\n")+1);
//remove carriage return
successPage = successPage.substring(
successPage.indexOf("\n")+1);
//get success page
successPage = successPage.substring(0,
successPage.indexOf("\n")-1);
}
//get OverWrite flag web variable from request
String overWrite;
if (file.indexOf("name=\"OverWrite\"") > 0)
{
overWrite = file.substring(
file.indexOf("name=\"OverWrite\""));
//remove carriage return
overWrite = overWrite.substring(
overWrite.indexOf("\n")+1);
//remove carriage return
overWrite = overWrite.substring(
overWrite.indexOf("\n")+1);
//get overwrite flag
overWrite = overWrite.substring(0,
overWrite.indexOf("\n")-1);
}
else
{
overWrite = "false";
}
//get OverWritePage web variable from request
String overWritePage="";
if (file.indexOf("name=\"OverWritePage\"") > 0)
{
overWritePage = file.substring(
file.indexOf("name=\"OverWritePage\""));
//remove carriage return
overWritePage = overWritePage.substring(
overWritePage.indexOf("\n")+1);
//remove carriage return
overWritePage = overWritePage.substring(
overWritePage.indexOf("\n")+1);
//get overwrite page
overWritePage = overWritePage.substring(0,
overWritePage.indexOf("\n")-1);
}
//get filename of upload file
String saveFile = file.substring(
file.indexOf("filename=\"")+10);
saveFile = saveFile.substring(0,
saveFile.indexOf("\n"));
saveFile = saveFile.substring(
saveFile.lastIndexOf("\\")+1,
saveFile.indexOf("\""));
/*remove boundary ers and other multipart/form-data
tags from beginning of upload file section*/
int pos; //position in upload file
//find position of upload file section of request
pos = file.indexOf("filename=\"");
//find position of content-disposition line
pos = file.indexOf("\n",pos)+1;
//find position of content-type line
pos = file.indexOf("\n",pos)+1;
//find position of blank line
pos = file.indexOf("\n",pos)+1;
/*find the location of the next boundary er
(ing the end of the upload file data)*/
int boundaryLocation = file.indexOf(boundary,pos)-4;
//upload file lies between pos and boundaryLocation
file = file.substring(pos,boundaryLocation);
//build the full path of the upload file
String fileName = new String(rootPath + directory +
saveFile);
//create File object to check for existence of file
File checkFile = new File(fileName);
if (checkFile.exists())
{
/*file exists, if OverWrite flag is off, give
message and abort*/
if (!overWrite.toLowerCase().equals("true"))
{
if (overWritePage.equals(""))
{
/*OverWrite HTML page URL not received, respond
with generic message*/
out.println("Sorry, file already exists.");
}
else
{
//redirect client to OverWrite HTML page
response.sendRedirect(overWritePage);
}
return;
}
}
/*create File object to check for existence of
Directory*/
File fileDir = new File(rootPath + directory);
if (!fileDir.exists())
{
//Directory doesn't exist, create it
fileDir.mkdirs();
}
//instantiate file output stream
fileOut = new FileOutputStream(fileName);
//write the string to the file as a byte array
fileOut.write(file.getBytes(),0,file.length());
if (successPage.equals(""))
{
/*success HTML page URL not received, respond with
generic success message*/
out.println(successMessage);
out.println("File written to: " + fileName);
}
else
{
//redirect client to success HTML page
response.sendRedirect(successPage);
}
}
else //request is not multipart/form-data
{
//send error message to client
out.println("Request not multipart/form-data.");
}
}
catch(Exception e)
{
try
{
//print error message to standard out
System.out.println("Error in doPost: " + e);
//send error message to client
out.println("An unexpected error has occurred.");
out.println("Error description: " + e);
}
catch (Exception f) {}
}
finally
{
try
{
fileOut.close(); //close file output stream
}
catch (Exception f) {}
try
{
in.close(); //close input stream from client
}
catch (Exception f) {}
try
{
out.close(); //close output stream to client
}
catch (Exception f) {}
}
}
}————————————————————————————————用Java实现断点续传(HTTP)
内容：
(一)断点续传的原理
(二)Java实现断点续传的关键几点
(三)断点续传内核的实现
关于作者
钟华 ([email protected])
2001 年 5 月(一)断点续传的原理
其实断点续传的原理很简单，就是在Http的请求上和一般的下载有所不同而已。
打个比方，浏览器请求服务器上的一个文时，所发出的请求如下：
假设服务器域名为wwww.sjtu.edu.cn，文件名为down.zip。
GET /down.zip HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-
excel, application/msword, application/vnd.ms-powerpoint, */*
Accept-Language: zh-cn
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)
Connection: Keep-Alive
服务器收到请求后，按要求寻找请求的文件，提取文件的信息，然后返回给浏览器，返回信息如下：
200
Content-Length=106786028
Accept-Ranges=bytes
Date=Mon, 30 Apr 2001 12:56:11 GMT
ETag=W/"02ca57e173c11:95b"
Content-Type=application/octet-stream
Server=Microsoft-IIS/5.0
Last-Modified=Mon, 30 Apr 2001 12:56:11 GMT
所谓断点续传，也就是要从文件已经下载的地方开始继续下载。所以在客户端浏览器传给
Web服务器的时候要多加一条信息--从哪里开始。
下面是用自己编的一个"浏览器"来传递请求信息给Web服务器，要求从2000070字节开始。
GET /down.zip HTTP/1.0
User-Agent: NetFox
RANGE: bytes=2000070-
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
仔细看一下就会发现多了一行RANGE: bytes=2000070-
这一行的意思就是告诉服务器down.zip这个文件从2000070字节开始传，前面的字节不用传了。
服务器收到这个请求以后，返回的信息如下：
206
Content-Length=106786028
Content-Range=bytes 2000070-106786027/106786028
Date=Mon, 30 Apr 2001 12:55:20 GMT
ETag=W/"02ca57e173c11:95b"
Content-Type=application/octet-stream
Server=Microsoft-IIS/5.0
Last-Modified=Mon, 30 Apr 2001 12:55:20 GMT
和前面服务器返回的信息比较一下，就会发现增加了一行：
Content-Range=bytes 2000070-106786027/106786028
返回的代码也改为206了，而不再是200了。
知道了以上原理，就可以进行断点续传的编程了。
(二)Java实现断点续传的关键几点
(1)用什么方法实现提交RANGE: bytes=2000070-。
当然用最原始的Socket是肯定能完成的，不过那样太费事了，其实Java的net包中提供了这种功能。代码如下：
URL url = new URL("http://www.sjtu.edu.cn/down.zip");
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection
();
//设置User-Agent
httpConnection.setRequestProperty("User-Agent","NetFox");
//设置断点续传的开始位置
httpConnection.setRequestProperty("RANGE","bytes=2000070");
//获得输入流
InputStream input = httpConnection.getInputStream();
从输入流中取出的字节流就是down.zip文件从2000070开始的字节流。
大家看，其实断点续传用Java实现起来还是很简单的吧。
接下来要做的事就是怎么保存获得的流到文件中去了。
保存文件采用的方法。
我采用的是IO包中的RandAccessFile类。
操作相当简单，假设从2000070处开始保存文件，代码如下：
RandomAccess oSavedFile = new RandomAccessFile("down.zip","rw");
long nPos = 2000070;
//定位文件指针到nPos位置
oSavedFile.seek(nPos);
byte[] b = new byte[1024];
int nRead;
//从输入流中读入字节流，然后写到文件中
while((nRead=input.read(b,0,1024)) > 0)
{
oSavedFile.write(b,0,nRead);
}怎么样，也很简单吧。
接下来要做的就是整合成一个完整的程序了。包括一系列的线程控制等等。(三)断点续传内核的实现
主要用了6个类，包括一个测试类。
SiteFileFetch.java负责整个文件的抓取，控制内部线程(FileSplitterFetch类)。
FileSplitterFetch.java负责部分文件的抓取。
FileAccess.java负责文件的存储。
SiteInfoBean.java要抓取的文件的信息，如文件保存的目录，名字，抓取文件的URL等。
Utility.java工具类，放一些简单的方法。
TestMethod.java测试类。
下面是源程序：
/*
**SiteFileFetch.java
*/
package NetFox;
import java.io.*;
import java.net.*;
public class SiteFileFetch extends Thread {
SiteInfoBean siteInfoBean = null; //文件信息Bean
long[] nStartPos; //开始位置
long[] nEndPos; //结束位置
FileSplitterFetch[] fileSplitterFetch; //子线程对象
long nFileLength; //文件长度
boolean bFirst = true; //是否第一次取文件
boolean bStop = false; //停止标志
File tmpFile; //文件下载的临时信息
DataOutputStream output; //输出到文件的输出流
public SiteFileFetch(SiteInfoBean bean) throws IOException
{
siteInfoBean = bean;
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
if(tmpFile.exists ())
{
bFirst = false;
read_nPos();
}
else
{
nStartPos = new long[bean.getNSplitter()];
nEndPos = new long[bean.getNSplitter()];
}}
public void run()
{
//获得文件长度
//分割文件
//实例FileSplitterFetch
//启动FileSplitterFetch线程
//等待子线程返回
try{
if(bFirst)
{
nFileLength = getFileSize();
if(nFileLength == -1)
{
System.err.println("File Length is not known!");
}
else if(nFileLength == -2)
{
System.err.println("File is not access!");
}
else
{
for(int i=0;i<nStartPos.length;i++)
{
nStartPos[i] = (long)(i*(nFileLength/nStartPos.length));
}
for(int i=0;i<nEndPos.length-1;i++)
{
nEndPos[i] = nStartPos[i+1];
}
nEndPos[nEndPos.length-1] = nFileLength;
}
}
//启动子线程
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
for(int i=0;i<nStartPos.length;i++)
{
fileSplitterFetch[i] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
nStartPos[i],nEndPos[i],i);
Utility.log("Thread " + i + " , nStartPos = " + nStartPos[i] + ", nEndPos = " + nEndPos[i]);
fileSplitterFetch[i].start();
}
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
nEndPos = " + nFileLength);
// fileSplitterFetch[nPos.length-1].start();
//等待子线程结束
//int count = 0;
//是否结束while循环
boolean breakWhile = false;
while(!bStop)
{
write_nPos();
Utility.sleep(500);
breakWhile = true;
for(int i=0;i<nStartPos.length;i++)
{
if(!fileSplitterFetch[i].bDownOver)
{
breakWhile = false;
break;
}
}
if(breakWhile)
break;
//count++;
//if(count>4)
// siteStop();
}
System.err.println("文件下载结束！");
}
catch(Exception e){e.printStackTrace ();}
}
//获得文件长度
public long getFileSize()
{
int nFileLength = -1;
try{
URL url = new URL(siteInfoBean.getSSiteURL());
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
httpConnection.setRequestProperty("User-Agent","NetFox");
int responseCode=httpConnection.getResponseCode();
if(responseCode>=400)
{
processErrorCode(responseCode);
return -2; //-2 represent access is error
}
String sHeader;
for(int i=1;;i++)
{
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
//Utility.log(in.readLine());
sHeader=httpConnection.getHeaderFieldKey(i);
if(sHeader!=null)
{
if(sHeader.equals("Content-Length"))
{
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
break;
}
}
else
break;
}
}
catch(IOException e){e.printStackTrace ();}
catch(Exception e){e.printStackTrace ();}
Utility.log(nFileLength);
return nFileLength;
}
//保存下载信息（文件指针位置）
private void write_nPos()
{
try{
output = new DataOutputStream(new FileOutputStream(tmpFile));
output.writeInt(nStartPos.length);
for(int i=0;i<nStartPos.length;i++)
{
// output.writeLong(nPos[i]);
output.writeLong(fileSplitterFetch[i].nStartPos);
output.writeLong(fileSplitterFetch[i].nEndPos);
}
output.close();
}
catch(IOException e){e.printStackTrace ();}
catch(Exception e){e.printStackTrace ();}
}
//读取保存的下载信息（文件指针位置）
private void read_nPos()
{
try{
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
int nCount = input.readInt();
nStartPos = new long[nCount];
nEndPos = new long[nCount];
for(int i=0;i<nStartPos.length;i++)
{
nStartPos[i] = input.readLong();
nEndPos[i] = input.readLong();
}
input.close();
}
catch(IOException e){e.printStackTrace ();}
catch(Exception e){e.printStackTrace ();}
}
private void processErrorCode(int nErrorCode)
{
System.err.println("Error Code : " + nErrorCode);
}
//停止文件下载
public void siteStop()
{
bStop = true;
for(int i=0;i<nStartPos.length;i++)
fileSplitterFetch[i].splitterStop();
}
}
/*
**FileSplitterFetch.java
*/
package NetFox;
import java.io.*;
import java.net.*;
public class FileSplitterFetch extends Thread {
String sURL; //File URL
long nStartPos; //File Snippet Start Position
long nEndPos; //File Snippet End Position
int nThreadID; //Thread's ID
boolean bDownOver = false; //Downing is over
boolean bStop = false; //Stop identical
FileAccessI fileAccessI = null; //File Access interface
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
{
this.sURL = sURL;
this.nStartPos = nStart;
this.nEndPos = nEnd;
nThreadID = id;
fileAccessI = new FileAccessI(sName,nStartPos);
}
public void run()
{
while(nStartPos < nEndPos && !bStop)
{
try{
URL url = new URL(sURL);
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
httpConnection.setRequestProperty("User-Agent","NetFox");
String sProperty = "bytes="+nStartPos+"-";
httpConnection.setRequestProperty("RANGE",sProperty);
Utility.log(sProperty);
InputStream input = httpConnection.getInputStream();
//logResponseHead(httpConnection);
byte[] b = new byte[1024];
int nRead;
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
{
nStartPos += fileAccessI.write(b,0,nRead);
//if(nThreadID == 1)
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
}
Utility.log("Thread " + nThreadID + " is over!");
bDownOver = true;
//nPos = fileAccessI.write (b,0,nRead);
}
catch(Exception e){e.printStackTrace ();}
}
}
//打印回应的头信息
public void logResponseHead(HttpURLConnection con)
{
for(int i=1;;i++)
{
String header=con.getHeaderFieldKey(i);
if(header!=null)
//responseHeaders.put(header,httpConnection.getHeaderField(header));
Utility.log(header+" : "+con.getHeaderField(header));
else
break;
}
}
public void splitterStop()
{
bStop = true;
}
}
/*
**FileAccess.java
*/
package NetFox;
import java.io.*;
public class FileAccessI implements Serializable{
RandomAccessFile oSavedFile;
long nPos;
public FileAccessI() throws IOException
{
this("",0);
}
public FileAccessI(String sName,long nPos) throws IOException
{
oSavedFile = new RandomAccessFile(sName,"rw");
this.nPos = nPos;
oSavedFile.seek(nPos);
}
public synchronized int write(byte[] b,int nStart,int nLen)
{
int n = -1;
try{
oSavedFile.write(b,nStart,nLen);
n = nLen;
}
catch(IOException e)
{
e.printStackTrace ();
}
return n;
}
}
/*
**SiteInfoBean.java
*/
package NetFox;
public class SiteInfoBean {
private String sSiteURL; //Site's URL
private String sFilePath; //Saved File's Path
private String sFileName; //Saved File's Name
private int nSplitter; //Count of Splited Downloading File
public SiteInfoBean()
{
//default value of nSplitter is 5
this("","","",5);
}
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
{
sSiteURL= sURL;
sFilePath = sPath;
sFileName = sName;
this.nSplitter = nSpiltter;
}
public String getSSiteURL()
{
return sSiteURL;
}
public void setSSiteURL(String value)
{
sSiteURL = value;
}
public String getSFilePath()
{
return sFilePath;
}
public void setSFilePath(String value)
{
sFilePath = value;
}
public String getSFileName()
{
return sFileName;
}
public void setSFileName(String value)
{
sFileName = value;
}
public int getNSplitter()
{
return nSplitter;
}
public void setNSplitter(int nCount)
{
nSplitter = nCount;
}
}
/*
**Utility.java
*/
package NetFox;
public class Utility {
public Utility()
{
}
public static void sleep(int nSecond)
{
try{
Thread.sleep(nSecond);
}
catch(Exception e)
{
e.printStackTrace ();
}
}
public static void log(String sMsg)
{
System.err.println(sMsg);
}
public static void log(int sMsg)
{
System.err.println(sMsg);
}
}
/*
**TestMethod.java
*/
package NetFox;
public class TestMethod {
public TestMethod()
{ ///xx/weblogic60b2_win.exe
try{
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
SiteFileFetch fileFetch = new SiteFileFetch(bean);
fileFetch.start();
}
catch(Exception e){e.printStackTrace ();}
}
public static void main(String[] args)
{
new TestMethod();
}
}
————————————————————————————————jsp文件操作之读取篇
2000-12-19 动网先锋 2000-11-28· coolknight·yesky 文件操作是网站编程的重要内容之一，asp关于文件操作讨论的已经很多了，让我们来看看jsp中是如何实现的。
这里用到了两个文件，一个jsp文件一个javabean文件，通过jsp中调用javabean可以轻松读取文本文件，注意请放置一个文本文件afile.txt到web根目录的test目录下，javabean文件编译后将class文件放到对应的class目录下(tomcat环境)。
Read.jsp<html>
<head>
<title>读取一个文件</title>
</head>
<body bgcolor="#000000">
<%--调用javabean --%>
<jsp:useBean id="reader" class="DelimitedDataFile" scope="request">
<jsp:setProperty name="reader" property="path" value="/test/afile.txt" />
</jsp:useBean><h3>文件内容:</h3><p><% int count = 0; %>
<% while (reader.nextRecord() != -1) { %>
<% count++; %>
<b>第<% out.print(count); %>行:</b>
<% out.print(reader.returnRecord()); %><br>
<% } %>
</p>
</body>
</html>
//DelimitedDataFile.java bean文件源代码
//导入java包
import java.io.*;
import java.util.StringTokenizer;public class DelimitedDataFile
{private String currentRecord = null;
private BufferedReader file;
private String path;
private StringTokenizer token;
//创建文件对象
public DelimitedDataFile()
{
file = new BufferedReader(new InputStreamReader(System.in),1);
}
public DelimitedDataFile(String filePath) throws FileNotFoundException
{
path = filePath;
file = new BufferedReader(new FileReader(path));
}
//设置文件路径
public void setPath(String filePath)
{
path = filePath;
try {
file = new BufferedReader(new
FileReader(path));
} catch (FileNotFoundException e) {
System.out.println("file not found");
}
}
//得到文件路径
public String getPath() {
return path;
}
//关闭文件
public void fileClose() throws IOException
{
file.close();
}
//读取下一行记录，若没有则返回-1
public int nextRecord()
{
int returnInt = -1;
try
{
currentRecord = file.readLine();
}
catch (IOException e)
{
System.out.println("readLine problem, terminating.");
}
if (currentRecord == null)
returnInt = -1;
else
{
token = new StringTokenizer(currentRecord);
returnInt = token.countTokens();
}
return returnInt;
} //以字符串的形式返回整个记录
public String returnRecord()
{return currentRecord;
}
}
谢谢各位的帮助,我终于搞定了,用的是JSPSMART组件,呵呵!但我想上传在数据库中,请问lijunjoy 兄弟给我详细指点好吗? 有谢!
相关连接也行!