用java的URL实现了一个简单的断点续传的列子，不为别的，假如你对断点续传不了解一看就明白了呵呵，算不上高深啊

package test;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.io.RandomAccessFile;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLConnection;

/* @className:TestDown.java

* @classDescription: 简单的java断点续传

* @author:jiangmianyue

* @createTime:2011-11-29

*/

public class TestDown {

public static void main(String[] args) {

URL url = null;

try {

url = new URL("http://172.16.1.33/newfile/e358beb5367341929614332e1a390dfb.apk");

} catch (MalformedURLException e) {

e.printStackTrace();

}

URLConnection httpConnection = null;

try {

// 建立连接

httpConnection = url.openConnection();

} catch (IOException e) {

e.printStackTrace();

}

// 设置ua

httpConnection.setRequestProperty("User-Agent","NetFox");

// 设置断点续传的开始位置 从100k开始

httpConnection.setRequestProperty("RANGE","bytes=102400-");

// 获得输入流

InputStream input = null;

try {

input = httpConnection.getInputStream();

} catch (IOException e) {

e.printStackTrace();

}

// 可以从多少字节开始写的文件类

RandomAccessFile oSavedFile = null;

try {

oSavedFile = new RandomAccessFile("d://down.apk","rw");

} catch (FileNotFoundException e) {

e.printStackTrace();

}

// 从第100K开始写

long nPos = 102400;

// 定位文件指针到 nPos 位置

try {

// 文件指针移动到那个位置

oSavedFile.seek(nPos);

} catch (IOException e) {

e.printStackTrace();

}

byte[] b = new byte[1024];

int nRead;

// 从输入流中读入字节流，然后写到文件中

try {

// int n =0;

while((nRead=input.read(b,0,1024)) > 0)

{

oSavedFile.write(b,0,nRead);

/**

* 第一次的时设置n的值到100的时候断开

* if(100 == n){

* break;

* }

*/

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

// 下面是一些请求头信息可以根据需要添加

private static void setHeader(URLConnection con) {

con.setRequestProperty("User-Agent", "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.3) Gecko/2008092510 Ubuntu/8.04 (hardy) Firefox/3.0.3");

con.setRequestProperty("Accept-Language", "en-us,en;q=0.7,zh-cn;q=0.3");

con.setRequestProperty("Accept-Encoding", "aa");

con.setRequestProperty("Accept-Charset", "ISO-8859-1,utf-8;q=0.7,*;q=0.7");

con.setRequestProperty("Keep-Alive", "300");

con.setRequestProperty("Connection", "keep-alive");

con.setRequestProperty("If-Modified-Since", "Fri, 02 Jan 2009 17:00:05 GMT");

con.setRequestProperty("If-None-Match", "\"1261d8-4290-df64d224\"");

con.setRequestProperty("Cache-Control", "max-age=0");

con.setRequestProperty("Referer", "http://www.dianping.com");

}

}

0

顶

1

踩

分享到：

2011-11-29 18:56

浏览 2817

评论