目录，文件操作：删除，创建，拷贝...

Question

String path = "c:\\aa";
file = new File(path);
if (file.exists()) {// 检查目录是否存在
// 目录存在，删除目录及下所有文件和目录
Runtime.getRuntime().exec("cmd.exe /c rd " + path + " /s/q");
}
file.mkdir();// 建立目录
System.out.println(path);
Runtime.getRuntime().exec("xcopy f:\\bb " + path + " /s/e");
如果目录不存在，可以创建目录成功，而且拷贝也成功；但是目录如何存在，删除可以，创建目录不成功，拷贝也不可以。请各位DX帮忙看看为什么？在此先谢谢。

Answer 1

Runtime.getRuntime().exec("cmd.exe /c rd " + path + " /s/q");是异步的

Answer 2

java 自己有删除，拷贝目录，等方法亚，你的功能我都做过呀，直接用java 的方法就可以了，可以不Runtime.getRuntime().exec 就可以实现亚，你可以尝试

Answer 3

/** 删除指定文件
 *  
 */
    public void deleteFile(String filename) {
       File f = new File(filename);
       if (!f.exists()) System.out.print("Delete: no such file or directory: " +filename);
       if (!f.canWrite()) System.out.print("Delete: write protected: " + filename);       if (f.isDirectory()) {
           String[] files = f.list();
           if (files.length > 0)
  System.out.print("Delete: directory not empty: " + filename);
       }       boolean success = f.delete();       if (!success) System.out.print("Delete: deletion failed");    System.out.print("delete");
   }

Answer 4

/**
 * 
 * @param filename 以有的文件(c:\a.doc)
 * @param copyto  要copy到的文件名称(d:\A.doc)
 * @throws IOException
 */
public static void copyFile(String filename,String copyto)throws IOException{
InputStream is=new FileInputStream(filename);
OutputStream streamOut = new FileOutputStream(copyto);//定义输出流
int byteRead = 0;
byte[] buffer = new byte[8192];
while ((byteRead = is.read(buffer, 0, 8192)) != -1) {
streamOut.write(buffer, 0, byteRead);
}
streamOut.close();
is.close();
}

Answer 5

/**
 * 删除文件夹下所有文件
 * 
 * @param filePath
 * @throws IOException
 */
public static void deleteDir(String filePath)throws IOException{
File path=new File(filePath);
if(path.exists()){
if(path.isFile()){
path.delete();
}else{
String[] fileList=path.list();
for(int i=0;i<fileList.length;i++){
File child=new File(path + "\\" +fileList[i]);
if(child.isFile()){
child.delete();
}else{
String childPath=child.toString();
deleteDir(childPath);
}
child.delete();
}
path.delete();
}
}
}

Answer 6

可以这样
Process process = Runtime.getRuntime().exec("cmd.exe /c rd " + path + " /s/q");
process.waitFor();
if (process.exitValue() == 0)
file.mkdir();
else
...

Answer 7

1。新建目录
               String filePath="root:/XXX/";
               filePath=filePath.toString();//中文转换
               File myFilePath=new File(filePath);
               if(!myFilePath.exists())
                  myFilePath.mkdir();
            2。新建文件
               String filePath="root:/XXX.XXX";
               filePath=filePath.toString();
               File myFilePath=new File(filePath);
               if(!myFilePath.exists())
                  myFilePath.createNewFile();
               FileWriter resultFile=new FileWriter(myFilePath);
               PrintWriter myFile=new PrintWriter(resultFile);
               String strContent = "新建文件".toString();
               myFile.println(strContent);
               resultFile.close();
             3。删除文件
               String filePath="root:/XXX.XXX";
               filePath=filePath.toString();
               java.io.File myDelFile=new java.io.File(filePath);
               myDelFile.delete();            4。文件拷贝
               int bytesum=0;
               int byteread=0; 
               InputStream inStream=new FileInputStream("root:/XXX.XXX");
               FileOutputStream fs=new FileOutputStream( "root:/../XXX.XXX");
               byte[]  buffer =new  byte[1444];
               int length;
               while ((byteread=inStream.read(buffer))!=-1)
                {
                     bytesum+=byteread;
                     System.out.println(bytesum);
                     fs.write(buffer,0,byteread);
                } 
               inStream.close();             5。整个文件夹拷贝
               String url1="C:/aaa";
               String url2="d:/java/";
               (new File(url2)).mkdirs();
               File[] file=(new File(url1)).listFiles();
               for(int i=0;i<file.length;i++){
                    if(file[i].isFile()){
                           file[i].toString();
                           FileInputStream input=new FileInputStream(file[i]);
                           FileOutputStream output=
                                 new 
            FileOutputStream(url2+"/"+(file[i].getName()).toString());
                           byte[] b=new byte[1024*5];
                           int len;
                           while((len=input.read(b))!=-1){
                                  output.write(b,0,len);
                            }
                           output.flush();
                           output.close();
                           input.close();
                    }
                }            6。文件下载
               String fileName = "zsc104.swf".toString();
               //读到流中
               InputStream inStream=new FileInputStream("c:/zsc104.swf");
               //设置输出的格式 
               response.reset(); 
               response.setContentType("bin");
               response.addHeader("Content-Disposition","attachment; 
                              filename=\""+fileName + "\"");
               //循环取出流中的数据 
              byte[] b = new byte[100]; 
              int len; 
              while((len=inStream.read(b)) >0) 
                    response.getOutputStream().write(b,0,len);  
              inStream.close(); 
            7。数据库字段中的文件下载
            <%@ page contentType="text/html; charset=gb2312" %>
            <%@ page import="java.sql.*"%>
            <%@ page import="java.lang.*" %>
            <%@ page import="java.io.*" %>
            <%@ page import="com.jspsmart.upload.*" %>
            <%@ page import="DBstep.iDBManager2000.*"%>
            <%
               int bytesum=0;
               int byteread=0;
               //打开数据縼E
               ResultSet result=null;
               String Sql=null;
               PreparedStatement prestmt=null; 
               DBstep.iDBManager2000 DbaObj=new DBstep.iDBManager2000();
               DbaObj.OpenConnection();
               //取得数据库中的数据
               Sql="select  *  from  t_local_zhongzhuan ";
               result=DbaObj.ExecuteQuery(Sql);
               result.next();
               //将数据库中的数据读到流中 
               InputStream inStream=result.getBinaryStream("content"); 
               FileOutputStream fs=new FileOutputStream( "c:/dffdsafd.doc");
               byte[]  buffer =new  byte[1444];
               int length;
               while ((byteread=inStream.read(buffer))!=-1){
                 out.println("<DT><B>"+byteread+"</B></DT>");
                 bytesum+=byteread;
                 System.out.println(bytesum);
                 fs.write(buffer,0,byteread);
                }
            %>
             8。把网页保存成文件
            <%@ page import="java.text.*"%>
            <%@ page import="java.util.*"%>
            <%@ page import="java.io.*"%>
            <%@ page import="java.net.*"%>
            <%
                URL stdURL = null;
                BufferedReader stdIn = null;
                PrintWriter stdOut = null;
                try {
                    stdURL = new URL("http://www.163.com");
                }catch (MalformedURLException e) {
                     throw e;
                }
               try {
                 stdIn = new BufferedReader(new 
            InputStreamReader(stdURL.openStream()));
                 stdOut = new PrintWriter(new BufferedWriter(new 
            FileWriter("c:/163.html")));
               }catch (IOException e) {
                }
               /***把URL指定的页面以流的形式读出，写成指定的文件***/
               try {
                  String strHtml = "";
                  while((strHtml = stdIn.readLine())!=null) {
                        stdOut.println(strHtml);
                  }
              }catch (IOException e) {
               throw e;
              }finally {
               try {
                 if(stdIn != null)
                   stdIn.close();
                 if(stdOut != null)
                   stdOut.close();
               }
               catch (Exception e) {
                 System.out.println(e);
               }
             }
            %>
             9。直接下载网上的文件
            <%@ page import="java.io.*"%>
            <%@ page import="java.net.*"%>
            <%
               int bytesum=0;
               int byteread=0;
               URL url = new URL("http://pimg.163.com/sms/micheal/logo.gif");
               URLConnection conn = url.openConnection();
               InputStream inStream = conn.getInputStream();
               FileOutputStream fs=new FileOutputStream( "c:/abc.gif");
               byte[]  buffer =new  byte[1444];
               int length;
               while ((byteread=inStream.read(buffer))!=-1){
                   out.println("<DT><B>"+byteread+"</B></DT>");
                   bytesum+=byteread;
                   System.out.println(bytesum);
                   fs.write(buffer,0,byteread);
               }
            %>