怎样实现照片上传

Question

图像上传的实质是读取源文件，如photo.jpg，成为内存中的byte[]对象。然后将byte[]对象通过流传送到远端即可。

Answer 1

//package  pub;import  java.io.*;
import  javax.servlet.*;
import  javax.servlet.http.*;public  class  upload
{
  private  static  String  newline  =  "\n";
  private  String  uploadDirectory  =  ".";
  private  String  ContentType  =  "";
  private  String  CharacterEncoding  =  "";
  private  ServletContext  application;  public upload(){  }  public  final  void  init(ServletContext  app) throws  ServletException
    {
      application  =  app;
    }
  private  String  getFileName(String  s)
    {
      int  i  =  s.lastIndexOf("\\");
      if(i<0||i>=s.length()-1)
        {
          i  =  s.lastIndexOf("/");
            if(i<0||i>=s.length()-1)
              return  s;
        }
           return  s.substring(i+1);
    }   public  void  setUploadDirectory(String  s)
    {
      if  (isVirtual(s))
        {
           uploadDirectory  =  application.getRealPath(s);
        } else
          {
             uploadDirectory  =  s;
           }
       File  testdir  =  new  File(uploadDirectory);
       if  (!testdir.exists()) {
          throw new IllegalArgumentException(String.valueOf((new 
 StringBuffer("Directory  '")).append(s).append("'  not  found  (1040).")));
         }
   }
   public  void  setContentType(String  s) {
     ContentType  =  s;
      int  j;
       if((j  =  ContentType.indexOf("boundary="))  !=  -1)
       {
        ContentType  =  ContentType.substring(j  +  9);
         ContentType  =  "--"  +  ContentType;
         }
   }
   public  void  setCharacterEncoding(String  s)
    {
       CharacterEncoding  =  s;
    }
   public String  uploadFile(HttpServletRequest  req) throws  ServletException,IOException
      {
         setCharacterEncoding(req.getCharacterEncoding());
         setContentType(req.getContentType());
         String  filename  =  uploadFile(req.getInputStream());
         return  filename;
      }
public String uploadFile(ServletInputStream servletinputstream) throws  ServletException, IOException
     {
        String  s5  =  null;
        String  filename  =  null;
        byte  Linebyte[]  =  new  byte[4096];
        byte  outLinebyte[]  =  new  byte[4096];
        int  ai[]  =  new  int[1];
        int  ai1[]  =  new  int[1];
        String  line;
        while((line= readLine(Linebyte, ai, servletinputstream, CharacterEncoding)) != null)
          {
            int  i  =  line.indexOf("filename=");
            if(i  >=  0)
              {
                line  =  line.substring(i  +  10);
                if((i  =  line.indexOf("\""))  >  0)
                  line  =  line.substring(0,  i);
                  break;
             }
          }
          filename  =  line;
          if(filename  !=  null  &&  !filename.equals("\""))
           {
             filename  =  getFileName(filename);
             for  (int  i=0;i<filename.length();i++)
              {
                if((int)filename.charAt(i)==32)
                 {
                  filename=filename.replace(filename.charAt(i),'_');
                 }
               }
         String sContentType=readLine(Linebyte,ai,servletinputstream, CharacterEncoding);
            if(sContentType.indexOf("Content-Type")  >=  0)
            readLine(Linebyte,  ai,  servletinputstream,  CharacterEncoding);
              //File(String  parent,  String  child)
              //Creates  a  new  File  instance  from  a  parent  pathname  string
              //and  a  child  pathname  string.
             File  file  =  new  File(uploadDirectory,  filename);
             //FileOutputStream(File  file)
             //Creates  a  file  output  stream  to  write  to  the  file  represented
             //by  the  specified  File  object.
              FileOutputStream  fileoutputstream  =  new  FileOutputStream(file);
               while((sContentType  =  readLine(Linebyte,  ai,  servletinputstream,  CharacterEncoding))  !=  null)
               {
               if(sContentType.indexOf(ContentType) == 0 && Linebyte[0] == 45)
               break;
               if(s5  !=  null)
               {
                //write(byte[]  b,  int  off,  int  len)
                //Writes  len  bytes  from  the  specified  byte  array  starting
                //at  offset  off  to  this  file  output  stream.
                fileoutputstream.write(outLinebyte,  0,  ai1[0]);
                fileoutputstream.flush();
                }
                 s5=readLine(outLinebyte,  ai1,  servletinputstream,  CharacterEncoding);
                  if(s5== null || s5.indexOf(ContentType) == 0 && outLinebyte[0] == 45)
                   break;
                   fileoutputstream.write(Linebyte,  0,  ai[0]);
                   fileoutputstream.flush();
               }
              byte  byte0;
             if(newline.length()  ==  1)
               byte0  =  2;
               else
               byte0  =  1;
               if(s5!=null&&outLinebyte[0]!=45&&ai1[0] > newline.length()  *  byte0)
               fileoutputstream.write(outLinebyte, 0, ai1[0] -  newline.length()  *  byte0);
               if(sContentType!=null&&Linebyte[0]!=45&&ai[0]>newline.length() * byte0)
               fileoutputstream.write(Linebyte,  0,  ai[0]  -  newline.length()  *  byte0);
                fileoutputstream.close();
              }
                return  filename;
        }
    private  boolean  isVirtual(String  s)
      {
        if(application.getRealPath(s)  !=  null)
        {
          java.io.File  file  =  new  java.io.File(application.getRealPath(s));
             return  file.exists();
         } else {
          return  false;
         }
       }
   private String readLine(byte Linebyte[],  int  ai[],  ServletInputStream  servletinputstream,  String  CharacterEncoding)
    {
      try {
      //readLine(byte[]  buffer,  int  offset,  int  length)
      //Reads  a  line  from  the  POST  data.
      ai[0]  =  servletinputstream.readLine(Linebyte,  0,  Linebyte.length);
       if(ai[0]  ==  -1)
       return null;
      } catch(IOException  _ex) {
        return  null;
      }
     try {
        if(CharacterEncoding  ==  null) {
         //用缺省的编码方式把给定的byte数组转换为字符串
         //String(byte[]  bytes,  int  offset,  int  length)
         return  new  String(Linebyte,  0,  ai[0]);
         }else{
         //用给定的编码方式把给定的byte数组转换为字符串
         //String(byte[]  bytes,  int  offset,  int  length,  String  enc)
          return  new  String(Linebyte,  0,  ai[0],  CharacterEncoding);
         }
    } catch(Exception  _ex){    }
  }
}
****************
                                                               file.html 
        <form    enctype="multipart/form-data"  method=post  action  =up.jsp> 
        请上传您的文件:<br> 
        <input  type=file  name  =  myfile><br> 
        <input  type=submit  value="提  交"> 
        </form> 
                                        up.jsp 
<%@  page  import  =  "pub.upload"  %> 
<% 
        String  Dir  =  "/upload/"; 
        upload  up  =  new  upload(); 
        up.init(application); 
        up.setUploadDirectory(Dir); 
                String  filename  =  up.uploadFile(request); 
        if  (filename  !=  null) 
        { 
                out.print("文件"+filename+"已经成功上传到"+Dir); 
        } 
%>