如何用Java客户端/applet通过HTTP POST上传文件

package com.lph;

import java.io.*;
import java.net.*;

public class ServletCom {

 public static void main(String[] args) throws Exception {

  HttpURLConnection conn = null;
  BufferedReader br = null;
  DataOutputStream dos = null;
  DataInputStream inStream = null;

  InputStream is = null;
  OutputStream os = null;
  boolean ret = false;
  String StrMessage = "";
  String exsistingFileName = "C://account.xls";

  String lineEnd = "/r/n";
  String twoHyphens = "--";
  String boundary = "*****";

  int bytesRead, bytesAvailable, bufferSize;

  byte[] buffer;

  int maxBufferSize = 1 * 1024 * 1024;

  String responseFromServer = "";

  String urlString = "http://localhost:8080/FileUpload/requestupload";

  try {
   // ------------------ CLIENT REQUEST

   FileInputStream fileInputStream = new FileInputStream(new File(
     exsistingFileName));

   // open a URL connection to the Servlet

   URL url = new URL(urlString);

   // Open a HTTP connection to the URL

   conn = (HttpURLConnection) url.openConnection();

   // Allow Inputs
   conn.setDoInput(true);

   // Allow Outputs
   conn.setDoOutput(true);

   // Don't use a cached copy.
   conn.setUseCaches(false);

   // Use a post method.
   conn.setRequestMethod("POST");

   conn.setRequestProperty("Connection", "Keep-Alive");

   conn.setRequestProperty("Content-Type",
     "multipart/form-data;boundary=" + boundary);

   dos = new DataOutputStream(conn.getOutputStream());

   dos.writeBytes(twoHyphens + boundary + lineEnd);
   dos.writeBytes("Content-Disposition: form-data; name=/"upload/";"
     + " filename=/"" + exsistingFileName + "/"" + lineEnd);
   dos.writeBytes(lineEnd);

   // create a buffer of maximum size

   bytesAvailable = fileInputStream.available();
   bufferSize = Math.min(bytesAvailable, maxBufferSize);
   buffer = new byte[bufferSize];

   // read file and write it into form...

   bytesRead = fileInputStream.read(buffer, 0, bufferSize);

   while (bytesRead > 0) {
    dos.write(buffer, 0, bufferSize);
    bytesAvailable = fileInputStream.available();
    bufferSize = Math.min(bytesAvailable, maxBufferSize);
    bytesRead = fileInputStream.read(buffer, 0, bufferSize);
   }

   // send multipart form data necesssary after file data...

   dos.writeBytes(lineEnd);
   dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

   // close streams

   fileInputStream.close();
   dos.flush();
   dos.close();

  } catch (MalformedURLException ex) {
   System.out.println("From ServletCom CLIENT REQUEST:" + ex);
  }

  catch (IOException ioe) {
   System.out.println("From ServletCom CLIENT REQUEST:" + ioe);
  }

  // ------------------ read the SERVER RESPONSE

  try {
   inStream = new DataInputStream(conn.getInputStream());
   String str;
   while ((str = inStream.readLine()) != null) {
    System.out.println("Server response is: " + str);
    System.out.println("");
   }
   inStream.close();

  } catch (IOException ioex) {
   System.out.println("From (ServerResponse): " + ioex);

  }

 }

}