java 多线程上载

java 多线程下载

package com.test;import java.io.IOException;public class Main {//public static final String ADD = "http://mat1.gtimg.com/www/iskin960/s01/s_b_1.1.0.png";//public static final String ADD = "http://mat1.gtimg.com/www/iskin960/logo_soso.png";//public static final String ADD = "http://ossweb-img.qq.com/upload/qqgg/dancer/1305786311_1837963180_10218_sPicName.jpg";//public static final String ADD = "http://dl_dir.qq.com/qqfile/qq/QQ2011/QQ2011Beta2.exe";public static final String FILE = "jay_picture_90.jpg";public static final String ADD = "http://www.ppig.com.cn/images/jay_picture_90.jpg";public static void main(String[] args) throws IOException {DownMain main=new DownMain(ADD,4);//package com.test;import java.io.IOException;public class Main {//public static final String ADD = "http://mat1.gtimg.com/www/iskin960/s01/s_b_1.1.0.png";//public static final String ADD = "http://mat1.gtimg.com/www/iskin960/logo_soso.png";//public static final String ADD = "http://ossweb-img.qq.com/upload/qqgg/dancer/1305786311_1837963180_10218_sPicName.jpg";//public static final String ADD = "http://dl_dir.qq.com/qqfile/qq/QQ2011/QQ2011Beta2.exe";public static final String FILE = "jay_picture_90.jpg";public static final String ADD = "http://www.ppig.com.cn/images/jay_picture_90.jpg";public static void main(String[] args) throws IOException {DownMain main=new DownMain(ADD,4);//参数1，下载地址，参数2：用多少线程main.download();}}main.download();}}

闲来无事 搞下java多线程下载，发发代码，以后改进改进

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下载线程类：

package com.test;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;import java.util.ArrayList;import java.util.Properties;public class DownTread implements Runnable {private String address;//链接地址private long start;//开始字节private long end;//结束字节数private ArrayList<DownData> data;//下载的文件数据private CallBack callBack;//下载完成,回调写入下载容private int cache;//缓存public DownTread(String address,long start,long end,CallBack callBack){this.address=address;this.start=start;this.end=end;this.callBack=callBack;Properties properties=new Properties();try {properties.load(this.getClass().getResourceAsStream("/sys.properties"));//读取配置文件的缓存cache=Integer.parseInt(properties.getProperty("cache"));} catch (IOException e) {e.printStackTrace();}}@Overridepublic void run() {try {callBack.befor(this);down();} catch (IOException e) {e.printStackTrace();callBack.error(this);}callBack.allFinish(this);}private void down()throws IOException{URL url=new URL(address);HttpURLConnection conn=(HttpURLConnection) url.openConnection();conn.setUseCaches(false);conn.setDoInput(true);conn.setDoOutput(false);conn.setRequestMethod("GET");conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1");conn.setRequestProperty("Range", "bytes="+start+"-"+end);conn.connect();System.out.println("线程:"+Thread.currentThread().getName()+conn.getHeaderFields().get("Content-Range"));data=new ArrayList<DownData>();InputStream bins=conn.getInputStream();byte [] bs=new byte[cache];long len=end-start+1;int dlen=0;long dstart=start;while((dlen=bins.read(bs))!=-1){if(dlen<len){data.add(new DownData(dstart,bs, dlen));len-=dlen;dstart+=dlen;}else {data.add(new DownData(dstart,bs, len));dstart+=len;}if(DownMain.isWriteing){callBack.finish(this);data.clear();}bs=new byte[cache];}bins.close();conn.disconnect();}public long getStart() {return start;}public long getEnd() {return end;}public ArrayList<DownData> getData() {return data;}interface CallBack {void befor(DownTread thread);void finish(DownTread downTread);//读取到一次数据void allFinish(DownTread thread);//该线程分配的任务下载完成void error(DownTread thread);//出现错误}}

?下载的数据包

package com.test;public class DownData {private long start;//该段数据在总文件中的位置private long len;private byte [] data;public DownData(long start,byte []data,long len){this.start=start;this.data=data;this.len=len;}public long getLen() {return len;}public byte[] getData() {return data;}public long getStart() {return start;}}

?下载主线程类：管理，把下载的文件数据写入文件

package com.test;import java.io.File;import java.io.IOException;import java.io.RandomAccessFile;import java.net.HttpURLConnection;import java.net.URL;import com.test.DownTread.CallBack;public class DownMain implements CallBack {private String address;private RandomAccessFile af;public static boolean isWriteing=true;private int dts=0;private int thread;public DownMain(String address,int thread) {this.address = address;this.thread=thread;}public void download() throws IOException {System.out.println("开始下载文件");URL url = new URL(this.address);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setUseCaches(false);conn.setDoInput(true);conn.setDoOutput(false);conn.setRequestMethod("GET");conn.setConnectTimeout(20000);conn.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1");System.out.println("开始连接文件");conn.connect();System.out.println(conn.getHeaderFields());if(conn.getResponseCode()==HttpURLConnection.HTTP_NOT_FOUND){System.out.println("找不到文件,连接失败！");return;}System.out.println("连接成功");System.out.println("文件大小：" + conn.getContentLength() + "字节");System.out.println("文件类型：" + conn.getContentType());long fileLength = conn.getContentLength();conn.disconnect();File file = new File("d:\\jay\" + Main.FILE);if (!file.exists()) {file.createNewFile();} else {file.delete();file.createNewFile();}af = new RandomAccessFile(file, "rw");long unit = fileLength / thread;long start = 0;long[][] task = new long[thread][2];for (int i = 0; i < thread; i++) {task[i][0] = start;start += unit;task[i][1] = start - 1;if (i == thread-1 && task[i][1] < fileLength) {task[i][1] = fileLength;}}/**/System.out.println("开始分段下载");for (int i = 0; i < thread; i++) {new Thread(new DownTread(address, task[i][0], task[i][1], this),"线程"+i).start();start += unit;dts++;}}@Overridepublic void finish(DownTread down) {try {synchronized (af) {isWriteing=false;for (DownData d : down.getData()) {af.seek(d.getStart());System.out.print("线程"+Thread.currentThread().getName()+"写入位置："+af.getFilePointer());af.write(d.getData(), 0, (int)d.getLen());System.out.println("-"+af.getFilePointer());}System.gc();isWriteing=true;}} catch (IOException e) {e.printStackTrace();}}@Overridepublic void allFinish(DownTread thread) {System.out.println("线程："+Thread.currentThread().getName()+"开始完成");synchronized (af) {dts--;if(dts==0){try {finish();} catch (IOException e) {e.printStackTrace();}}}}@Overridepublic void befor(DownTread thread) {System.out.println("线程："+Thread.currentThread().getName()+"开始下载");}@Overridepublic void error(DownTread thread) {System.out.println("线程："+Thread.currentThread().getName()+"出现错误");}private void finish() throws IOException{System.out.println("全部下载完成！");af.close();}}

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