java实现http下载文件_用java 实现 http文件下载

import java.io.InputStream;

import java.io.RandomAccessFile;

import java.net.HttpURLConnection;

import java.net.URL;

public class DownLoad {

public void down(){

String path1 = "http://localhost:8080/wallpaper/aa/aa.txt";

String path2 = "D:/aa.txt";

File file2 = new File(path2);

try{

System.out.println("下载");

URL file1 = new URL(path1);

HttpURLConnection httpConnection = (HttpURLConnection)file1.openConnection();

httpConnection.disconnect();

//设置User-Agent

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

//设置断点续传的开始位置

httpConnection.setRequestProperty("RANGE", "bytes="+5+"-");

//获得输入流

InputStream input = httpConnection.getInputStream();

int filesize1 = (int) file2.length();

byte[] buff = new byte[1024];

int t = 0;

RandomAccessFile randomFile = new RandomAccessFile(file2, "rw");

// 文件长度，字节数

long fileLength = randomFile.length();

int nPos = 5;

randomFile.seek(nPos);

while(-1 != (t = input.read(buff, 0, buff.length))){

randomFile.write(buff, 0,t);

randomFile.close();

}        System.out.println("文件下载完毕！");                  }catch(Exception e){      e.printStackTrace();           }         }        public static void main(String[] args) {  DownLoad d = new DownLoad();  d.down(); }}