Java 多线程断点续传 (基于HTTP)
http://wenku.baidu.com/view/57fd6d8002d276a200292eca.html
package com.itheima.net.socket;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.io.Serializable;
import java.net.HttpURLConnection;
import java.net.URL;
/**
* 多线程断点续传 基于 (HTTP)
* @author Bin
* Windows NT 6.1
*/
public class TextThreadsAndPointAdd {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String webAddr="http://nchc.dl.sourceforge.net/project/jtidy/JTidy/r938/jtidy-r938.zip";
String fileDir="F:/temp";
String fileName="ss.zip";
int count=5;
new TextThreadsAndPointAdd(webAddr,fileDir,fileName,count);
}
public TextThreadsAndPointAdd(String webAddr,String fileDir,String fileName,int count) {
try {
TranBean bean=new TranBean(webAddr,fileDir,fileName,count);
ControlFileFetch fileFetch=new ControlFileFetch(bean);
fileFetch.start();
} catch (Exception e) {
System.out.println("多线程下载文件出错:"+e.getMessage());
System.exit(1);
}
}
}
//扩展多线程类,负责文件的抓取,控制内部线程
class ControlFileFetch extends Thread{
TranBean tranBean=null; //扩展信息bean
long [] startPosition; //开始位置
long [] endPosition; //结束位置
FileFetch[] childThread; //子线程对象
long fileLength; //文件长度
boolean isFitstGet=true; //是否第一次去文件
boolean isStopGet=false; //停止标志
File fileName; //文件下载的临时信息
DataOutputStream output; //输出到文件的输出流
public ControlFileFetch(TranBean tranBean){
this.tranBean=tranBean;
fileName=new File(tranBean.getFileDir()+File.separator+tranBean.getFileName()+".info"); //创建文件
System.out.println(tranBean.getFileDir()+File.separator+tranBean.getFileName()+".info");
if(fileName.exists()){
isFitstGet=false;
readInfo();
}else{
startPosition=new long[tranBean.getCount()];
endPosition =new long[tranBean.getCount()];
}
}
public void run(){
try {
if(isFitstGet){ //第一次读取文件
fileLength=getFieldSize(); //调用方法获取文件长度
if(fileLength==-1){
System.err.println("文件长度为止");
}else if(fileLength==-2){
System.err.println("不能访问文件");
}else{
System.out.println("文件的长度:"+fileLength);
//循环划分 每个线程要下载的文件的开始位置
for (int i = 0; i < startPosition.length; i++) {
startPosition[i]=(long)(i*(fileLength/startPosition.length));
}
//循环划分每个线程要下载的文件的结束位置
for (int i = 0; i < endPosition.length-1; i++) {
endPosition[i]=startPosition[i+1];
}
//设置最后一个 线程的下载 结束位置 文件的的长度
endPosition[endPosition.length-1]=fileLength;
}
}
//创建 子线程数量的数组
childThread=new FileFetch[startPosition.length];
for (int i = 0; i < startPosition.length; i++) {
childThread[i]=new FileFetch(tranBean.getWebAddr(), tranBean.getFileDir()+File.separator+tranBean.getFileName(), startPosition[i], endPosition[i], i);
Log.log("线程"+(i+1)+",的开始位置="+startPosition[i]+",结束位置="+endPosition[i]);
childThread[i].start();
}
boolean breakWhile=false;
while (!isStopGet) {
savePosition();
Log.sleep(500);//
breakWhile=true;
for (int i = 0; i < startPosition.length; i++) { //循环实现下载文件
if(!childThread[i].downLoadOver){
breakWhile=false;
break;
}
}
if(breakWhile)
break;
}
System.err.println("文件下载结束!");
} catch (Exception e) {
System.out.println("下载文件出错:"+e.getMessage());
}
}
//保存下载信息(文件指针信息)
private void savePosition() {
try {
output=new DataOutputStream(new FileOutputStream(fileName));
output.writeInt(startPosition.length);
for (int i = 0; i < startPosition.length; i++) {
output.writeLong(childThread[i].startPosition);
output.writeLong(childThread[i].endPosition);
}
output.close();
} catch (Exception e) {
System.out.println("保存下载信息出错:"+e.getMessage());
}
}
//获得文件的长度
public long getFieldSize(){
int fileLength=-1;
try {
URL url=new URL(tranBean.getWebAddr()); //根据网址传入网址创建URL对象
//打开连接对象
HttpURLConnection httpConnection=(HttpURLConnection)url.openConnection();
//设置描述发出HTTP请求的终端信息
httpConnection.setRequestProperty("User-Agent", "NetFox");
int responseCode=httpConnection.getResponseCode();
//表示不能访问文件
if(responseCode>=400){
errorCode(responseCode);
return -2;
}
String head;
for (int i = 1; ; i++) {
head=httpConnection.getHeaderFieldKey(i); //获取文件头部信息
if(head !=null){
if(head.equals("Content-Length")){ //根据头部信息获取文件长度
fileLength=Integer.parseInt(httpConnection.getHeaderField(head));
break;
}
}else{
break;
}
}
} catch (Exception e) {
System.out.println("获取文件长度出错:"+e.getMessage());
}
Log.log("文件长度"+fileLength);
return fileLength;
}
private void errorCode(int errorCode){
System.out.println("错误代码:"+errorCode);
}
//读取文件指针位置
private void readInfo(){
try {
//创建数据输出流
DataInputStream input=new DataInputStream(new FileInputStream(fileName));
int count=input.readInt(); //读取分成的线程下载个数
startPosition=new long[count]; //设置开始线程
endPosition=new long[count]; //设置结束线程
for (int i = 0; i < startPosition.length; i++) {
startPosition[i]=input.readLong(); //读取每个线程的开始位置
endPosition[i]=input.readLong(); //读取每个线程的结束位置
}
input.close();
} catch (Exception e) {
System.out.println("读取文件指针位置出错:"+e.getMessage());
}
}
}
//扩展线程类,实现部分文件的抓取
class FileFetch extends Thread{
String webAddr; //网址
long startPosition; //开始位置
long endPosition; //结束位置
int threadID; //线程编号
boolean downLoadOver=false; //下载结束
boolean isStopGet=false; //是否停止请求
FileAccess fileAccessI=null; //存储文件的类
public FileFetch(String surl,String sname, long startPosition, long endPosition,
int threadID) throws IOException {
this.webAddr = surl;
this.startPosition = startPosition;
this.endPosition = endPosition;
this.threadID = threadID;
this.fileAccessI = new FileAccess(sname,startPosition);
}
//实现线程的方法
public void run(){
while (startPosition < endPosition && !isStopGet) {
try {
URL url=new URL(webAddr); //根据网络资源创建URL对象
HttpURLConnection httpConnection=(HttpURLConnection)url.openConnection(); //创建 打开的连接对象
//设置描述发出的HTTP请求的终端的信息
httpConnection.setRequestProperty("User-Agent", "NetFox");
String sproperty="byte="+startPosition+"-";
httpConnection.setRequestProperty("RANGE", sproperty);
Log.log(sproperty);
//获取 网络资源的输入流
InputStream input=httpConnection.getInputStream();
byte[] b=new byte[1024];
int nRead;
//循环将文件下载制定目录
while ((nRead=input.read(b, 0, 1024))>0 && startPosition < endPosition && !isStopGet) {
startPosition+=fileAccessI.write(b, 0, nRead); //调用方法将内容写入文件
}
Log.log("线程\t"+(threadID+1)+"\t结束....");
downLoadOver=true;
} catch (Exception e) {
e.printStackTrace();
}
}
}
//打印回应的头的信息
public void logResponseHead(HttpURLConnection con){
for (int i = 1; ; i++) {
String header=con.getHeaderFieldKey(i); //循环答应回应的头信息
if(header!=null){
Log.log(header+":"+con.getHeaderField(header));
}else
break;
}
}
public void splitterStop(){
isStopGet=true;
}
}
//存储文件的类
class FileAccess implements Serializable{
RandomAccessFile saveFile; //要保存的文件
long position;
public FileAccess() throws IOException {
this("",0);
}
public FileAccess(String sname, long position) throws IOException {
this.saveFile =new RandomAccessFile(sname, "rw"); //创建随机读取对象, 以 读/写的方式
this.position = position;
saveFile.seek(position); //设置指针位置
}
//将字符数据 写入文件
public synchronized int write(byte[] b,int start,int length){
int n=-1;
try {
saveFile.write(b,start,length);
n=length;
} catch (Exception e) {
e.printStackTrace();
}
return n;
}
}
//传输保存信息的类
class TranBean {
private String webAddr; //下载地址
private String fileDir; //下载到指定的目录
private String fileName; //下载后文件的新名字
private int count; //文件分几个线程下载, 默认为 3个
public TranBean() { //默认的构造方法
this("","","",3);
} //带参数的构造方法
public TranBean(String webAddr, String fileDir, String fileName, int count) {
this.webAddr = webAddr;
this.fileDir = fileDir;
this.fileName = fileName;
this.count = count;
}
public String getWebAddr() {
return webAddr;
}
public void setWebAddr(String webAddr) {
this.webAddr = webAddr;
}
public String getFileDir() {
return fileDir;
}
public void setFileDir(String fileDir) {
this.fileDir = fileDir;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
}
//线程运行信息显示的日志类
class Log{
public Log(){}
public static void sleep(int nsecond){
try {
Thread.sleep(nsecond);
} catch (Exception e) {
System.out.println("线程沉睡");
}
}
public static void log(String message){ //显示日志信息
System.err.println(message);
}
public static void log(int message){ //显示日志信息
System.err.println(message);
}
}