把你要下载的文件做成超级链接，可以不用任何组件
比如说
下载一个word文档
<a href="名称.doc">名称.doc</a>
路径你自己写
import java.io.File
import java.io.FileNotFoundException
import java.io.IOException
import java.io.InputStream
import java.io.RandomAccessFile
import java.net.HttpURLConnection
import java.net.ProtocolException
import java.net.URI
import java.net.URL
import java.util.Random
/**
*
* 实现了下载的功能*/
public class SimpleTh {
public static void main(String[] args){
// TODO Auto-generated method stub
//String path = "http://www.7cd.cn/QingTengPics/倩女幽魂.mp3"//MP3下载的地址
String path ="http://img.99luna.com/music/%CF%EB%C4%E3%BE%CD%D0%B4%D0%C5.mp3"
try {
new SimpleTh().download(path, 3)//对象调用下载的方法
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace()
}
}
public static String getFilename(String path){//获得文件的名字
return path.substring(path.lastIndexOf('/')+1)
}
public void download(String path,int threadsize) throws Exception//下载的方法
{//参数 下载地址，线程数量
URL url = new URL(path)
HttpURLConnection conn = (HttpURLConnection)url.openConnection()//获取HttpURLConnection对象
conn.setRequestMethod("GET")//设置请求格式，这里是GET格式
conn.setReadTimeout(5*1000)//
int filelength = conn.getContentLength()//获取要下载文件的长度
String filename = getFilename(path)
File saveFile = new File(filename)
RandomAccessFile accessFile = new RandomAccessFile(saveFile, "rwd")
accessFile.setLength(filelength)
accessFile.close()
int block = filelength%threadsize ==0?filelength/threadsize:filelength/threadsize+1
for(int threadid = 0threadid<=threadsizethreadid++){
new DownloadThread(url,saveFile,block,threadid).start()
}
}
private final class DownloadThread extends Thread{
private URL url
private File saveFile
private int block//每条线程下载的长度
private int threadid//线程id
public DownloadThread(URL url,File saveFile,int block,int threadid){
this.url = url
this.saveFile= saveFile
this.block = block
this.threadid = threadid
}
@Override
public void run() {
//计算开始位置的公式：线程id*每条线程下载的数据长度=？
//计算结束位置的公式：（线程id+1）*每条线程下载数据长度-1=？
int startposition = threadid*block
int endposition = (threadid+1)*block-1
try {
try {
RandomAccessFile accessFile = new RandomAccessFile(saveFile, "rwd")
accessFile.seek(startposition)//设置从什么位置写入数据
HttpURLConnection conn = (HttpURLConnection)url.openConnection()
conn.setRequestMethod("GET")
conn.setReadTimeout(5*1000)
conn.setRequestProperty("Range","bytes= "+startposition+"-"+endposition)
InputStream inStream = conn.getInputStream()
byte[]buffer = new byte[1024]
int len = 0
while((len = inStream.read(buffer))!=-1){
accessFile.write(buffer, 0, len)
}
inStream.close()
accessFile.close()
System.out.println("线程id："+threadid+"下载完成")
} catch (FileNotFoundException e) {
e.printStackTrace()
}
} catch (IOException e) {
e.printStackTrace()
}
}
}
}
java实现超链接下载方法如下：
response.setHeader("Content-disposition","attachmentfilename="下载的文件名字)备注：让response调用setheader方法添加下载的头给客户的浏览器，浏览器收到该头后就会打开相应的下载对话框。
