使用Java怎么实现一个多线程断点下载?针对这个问题,这篇文章详细介绍了相对应的分析和解答,希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。
Java多线程断点下载原理如图:
import java.io.BufferedReader;,
import java.io.File,
import java.io.FileInputStream,
import java.io.InputStream,
import java.io.InputStreamReader,
import java.io.RandomAccessFile,
import java.net.HttpURLConnection,
import java.net.URL,
,
{public class MutileThreadDownload /* *,才能
,,*,线程的数量,
,,*/,
private 才能static int threadCount =, 3,,
,/* *,才能
,,*,每个下载区块的大小,
,,*/,
private 才能static long blocksize;,
,/* *,才能
,,*,正在运行的线程的数量,
,,*/,
private 才能static int runningThreadCount;,
,/* *,才能
,,*,@param args
,,*,@throws Exception
,,*/,
public 才能;static void main (String [], args), throws Exception {,
,,,//,服务器文件的路径,
,,,String path =,“http://192.168.1.100:8080 ff.exe",,
,,,URL URL =, new URL(路径),,
,,,HttpURLConnection conn =, (HttpURLConnection), url.openConnection (),,
,,,conn.setRequestMethod (“GET");,
,,,conn.setConnectTimeout (5000),,
,,,int code =, conn.getResponseCode (),,
,,,if (code ==, 200), {,
,,,,,long size =, conn.getContentLength();//,得到服务端返回的文件的大小,
,,,,,System.out.println(“服务器文件的大小:“,+,大小),,
,,,,,blocksize =, size /, threadCount;,
,,,,,//,1。首先在本地创建一个大小跟服务器一模一样的空白文件只
,,,,,File File =, new 文件(“temp.exe");,
,,,,,RandomAccessFile raf =, new RandomAccessFile(文件,,“rw"),,
,,,,,raf.setLength(大小),,
,,,,,//,2。开启若干个子线程分别去下载对应的资源又是;
,,,,,runningThreadCount =, threadCount;,
,,,,,for (int 小姐:=,1;,小姐:& lt;=, threadCount;,我+ +),{,
,,,,,,,long startIndex =,(小姐,安康;1),*,blocksize;,
,,,,,,,long endIndex =,小姐:*,blocksize 作用;1;,
,,,,,,,if (小姐:==,threadCount), {,
,,,,,,,,,//,最后一个线程,
,,,,,,,,,endIndex =, size 作用;1;,
,,,,,,,},
,,,,,,,System.out.println(“开启线程:“,+,小姐:+,“下载的位置:“,+,startIndex +,“~”,
,,,,,,,,,,,+,endIndex),,
,,,,,,,new DownloadThread(路径,,我,,startIndex,, endIndex) .start (),,
,,,,,},
,,,},
,,,conn.disconnect (),,
,,},
,
private 才能static class DownloadThread extends Thread {,
,,,private int threadId;,
,,,private long startIndex;,
,,,private long endIndex;,
,,,private String 路径;,
,
,,,public DownloadThread (String 路径,int threadId,, long startIndex,,
,,,,,,,long endIndex), {,
,,,,,this.path =,路径;,
,,,,,this.threadId =, threadId;,
,,,,,this.startIndex =, startIndex;,
,,,,,this.endIndex =, endIndex;,
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