java多线程抓不到断点_Java多线程断点下载, 总有两个临时记录文件不能删除?

冷不防 2022-11-06 10:50 134阅读 0赞

代码如下:

package com.gzy.multithreaddownload;

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;

/\*\*

\* 多线程断点下载

\* @author GZY

\*/

public class MultiDownload \{

private int threadCount = 3;// 线程总数

private int finishedThread = 0;// 已经完成的线程数

/\*\*

\* 下载方法

\*/

public void download() \{

String path = "http://192.168.1.102:8080/vbox.exe";

try \{

URL url = new URL(path);

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setRequestMethod("GET");

conn.setConnectTimeout(5000);

conn.setReadTimeout(5000);

int responseCode = conn.getResponseCode();

if(responseCode == 200)\{

long length = conn.getContentLengthLong();// 拿到所请求资源文件的长度

File file = new File(getFileName(path));

RandomAccessFile raf = new RandomAccessFile(file, "rw");

raf.setLength(length);// 设置文件大小

raf.close();

long blocksize = length / threadCount;// 计算每个子线程应该下载的大小

for(int i = 0; i < threadCount; i++) \{

long startIndex = i \* blocksize;// 每个线程下载的开始位置

long endIndex = (i + 1) \* blocksize - 1;// 每个线程下载的结束位置

if(i == threadCount - 1) \{// 如果是最后一个线程，那么结束位置写死

endIndex = length - 1;

System.out.println("线程" + i + "的下载区间是：" + startIndex + "---" + endIndex);

// 开启子线程断点下载类开始下载

new DownloadThread(path, i, startIndex, endIndex).start();

conn.disconnect();

\} catch (Exception e) \{

e.printStackTrace();

/\*\*

\* 子线程(断点)下载类

\* @author GZY

\*/

class DownloadThread extends Thread \{

String path;

int threadId;

long startIndex, endIndex;

public DownloadThread(String path, int threadId, long startIndex,

long endIndex) \{

this.path = path;

this.threadId = threadId;

this.startIndex = startIndex;

this.endIndex = endIndex;

@Override

public void run() \{

// 再次发送http请求，下载原文件

try \{

long total = 0;// n. 总数，合计

File positionFile = new File(getFileName(path) + threadId + ".txt");// 用来保存total

// 判断是否为断点续传

if(positionFile.exists() && positionFile.length() > 0) \{

FileInputStream fis = new FileInputStream(positionFile);

BufferedReader br = new BufferedReader(new InputStreamReader(fis));

String totalStr = br.readLine();

total = Long.valueOf(totalStr);

startIndex += total;

System.out.println("线程" + threadId + "已经下载的大小: " + total);

br.close();

fis.close();

URL url = new URL(path);

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setRequestMethod("GET");

conn.setConnectTimeout(5000);

conn.setReadTimeout(5000);

// 设置本次http请求所请求的数据的区间 TODO

conn.setRequestProperty("Range", "bytes=" + startIndex + "-" + endIndex);

int responseCode = conn.getResponseCode();

System.out.println("responseCode=" + responseCode);

if(responseCode == 206) \{

InputStream is = conn.getInputStream();// 此时流中自由三分之一的数据

File file = new File(getFileName(path));

RandomAccessFile raf = new RandomAccessFile(file, "rw");

//把文件的写入位置移动至startIndex

raf.seek(startIndex);// seek vt. 寻求；寻找；探索；搜索

byte\[\] buffer = new byte\[1024 \* 1024\];

int len = -1;

while ((len = is.read(buffer)) != -1) \{

raf.write(buffer, 0, len);

total += len;

RandomAccessFile positionRaf = new RandomAccessFile(positionFile, "rwd");

positionRaf.write(String.valueOf(total).getBytes());

positionRaf.close();

System.out.println("线程" + threadId + "下载完毕!!!");

is.close();

raf.close();

finishedThread++;

synchronized (MultiDownload.class) \{

if(finishedThread == threadCount) \{

System.out.println("全部下载完毕, 开始删除positionFile");

for(int i = 0; i < threadCount; i++) \{

File f = new File(getFileName(path) + threadId + ".txt");

System.out.println(f.delete());

finishedThread = 0;

\} catch (Exception e) \{

e.printStackTrace();

/\*\*

\* 通过路径获取资源文件名

\* @param path

\* @return

\*/

private String getFileName(String path) \{

int index = path.lastIndexOf("/") + 1;

return path.substring(index);

public static void main(String\[\] args) \{

new MultiDownload().download();

java多线程抓不到断点_Java多线程断点下载, 总有两个临时记录文件不能删除?

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