1 package com.thread;  2   3 import java.io.File;  4 import java.io.IOException;  5 import java.io.InputStream;  6 import java.io.RandomAccessFile;  7 import java.net.HttpURLConnection;  8 import java.net.URL;  9  10 public class MultiDownLoad { 11     private final static int threadCount = 4; 12      13     public static void main(String[] args) throws Exception { 14         URL url = new URL("http://ubmcmm.baidustatic.com/media/v1/0f000Qk-RgkVYN5NV_NaO6.jpg"); 15         HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 16         long contentLength = conn.getContentLengthLong(); 17         long perLength = contentLength/threadCount; 18         File file = new File("E:/123.jpg"); 19         //为每个线程分配一个随机写入流 20         RandomAccessFile[] raf = new RandomAccessFile[threadCount]; 21         InputStream[]is = new InputStream[threadCount]; 22         for(int i=0;i