downloader.java

用Java编写的一个可下载MP3

package org.serain.shmily.downloadMusic;

import java.io.*;
import java.net.*;
import org.serain.shmily.vo.DownloadTask;

public class Downloader extends Thread{
	private DownloadTask task;
	private String url;
	private String savePath;
	private String fileName;
        private boolean loading=true;
	
	public Downloader(DownloadTask task,String savePath){
                this.task=task;
		this.savePath=savePath;
                this.url=task.getMusicUrl();
		String[] s=url.split("/");
		this.fileName=s[s.length-1];
	}
        public void finish(){
            task.setState("finish");
        }
        public void pause(){
            task.setState("pause");
        }
        public void goon(){
            task.setState("download");
        }

	public void run(){
		try{
			URL u=new URL(url);
			task.setTotalBytes(u.openConnection().getContentLength());
			task.setTimeRemain(task.getTotalBytes()/20000+"秒");
			InputStream is=u.openStream();
			BufferedInputStream bis=new BufferedInputStream(is);
			FileOutputStream fos=new FileOutputStream(savePath+fileName);
			BufferedOutputStream bos=new BufferedOutputStream(fos);
			byte[] buffer=new byte[1024 * 10];
			int len;
			int timeTake=0;
			//int flag=0;
			int finishBytes=0;
			while(!(task.getState().equals("finish"))){
				if(task.getState().equals("pause")){
                                    sleep(10000);//暂停时候睡眠10秒，防止无限循环占用系统资源
				}else if(task.getState().equals("download")){					
					long start=System.currentTimeMillis();
					if((len=bis.read(buffer))==-1){
						task.setState("finish");
						break;
					}
					bos.write(buffer,0,len);
					long end = System.currentTimeMillis();
					long time=end-start;
					timeTake =timeTake+(int)time; 
					finishBytes+=len;
					task.setFinishBytes(finishBytes);
					
					//if(flag%20==0){//每20次设置一次     	
						//设置进度
						float proess=(float)finishBytes/(float)task.getTotalBytes();
						task.setProess((int)(proess*100)+"%");
						task.setTimeTake(timeTake/1000 + "秒");
						if(time!=0){
							
							//设置即时速度
							int speed=len/(int)time;		
							task.setSpeed(speed+"kb/秒");
							
							//设置剩余时间
							int timeRemain;
							if(speed!=0){
								timeRemain=(task.getTotalBytes()-task.getFinishBytes())/speed;
								task.setTimeRemain(timeRemain/1000 +"秒");
							}	
						}
					//	System.out.println(fileName+"finishbytes:"+task.getFinishBytes()+"  proess:"+task.getProess()+"  speed: "+task.getSpeed()+"  timeTake:"+task.getTimeTake()+"  timeremain:"+task.getTimeRemain());
					//}
					//flag+=1;
				}
			    
			}
			is.close();
			fos.close();
		}catch(Exception e){
			e.printStackTrace();
			try {
				throw new Exception("下载出现错误");
			} catch (Exception e1) {
				e1.printStackTrace();
			}
		}
                
	}
	public void setTaskState(String state){
		task.setState(state);
	}
	public String getTaskState(){
		return task.getState();
	}

}