downloader.java

是一个java写的 可以输入要下的歌名

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package mymp3.downloader;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import mymp3.AppConfig;
/**
 *
 * @author huliqing
 */
public class Downloader extends Thread{
    private int state;  // 状态
    public static final int STATE_STOPPED = 0;  // 停止的
    public static final int STATE_LOADING = 1;  // 运行的
    public static final int STATE_PAUSED = 2;   // 暂停的
    public static final int STATE_OK = 3;       // 完成的
    
    private TaskModel task;
    private InputStream in;
    private OutputStream out;
    private byte[] buff;
    private int timeUsed;
    private int readBytes;
    private int totalBytes;
    private int speed;
    private final static int BUFFER_SIZE = 1024 * 10;
    private File file;    // 完整的文件保存路径
    
    public Downloader(TaskModel taskModel) {
        this.task = taskModel;
        Thread tt = new Thread(new Init());
        tt.start();
    }
    
    private class Init implements Runnable {
        public void run() {
            init();
        }
    }
    
    private void init() {
        try {
            if (totalBytes <= 0) {
                URL u = new URL(task.getUrl());
                totalBytes = u.openConnection().getContentLength();
            }
        } catch (Exception ex) {
            System.out.println("Exception:" + this.getClass().getName());
        }
    }
    
    @Override
    public void run() {
        makeName(); // 由主线程检查并设置文件名
        File processFile = new File(file.getAbsolutePath() + "_");  // 下载中的文件名
        try {
            if (totalBytes <= 0) {
                init();
            }
            URL u = new URL(task.getUrl());
            in = u.openStream();
            BufferedInputStream bis = new BufferedInputStream(in);
            buff = new byte[BUFFER_SIZE];
            out = new FileOutputStream(processFile);
            BufferedOutputStream bos = new BufferedOutputStream(out);
            int len;
            while (readBytes < totalBytes) {
                long start = System.currentTimeMillis();
                len = bis.read(buff, 0, buff.length);
                bos.write(buff, 0, len);
                long end = System.currentTimeMillis();
                timeUsed += (end - start);
                readBytes += len;
                synchronized (this) {
                    if (isPaused()) {
                        try {
                            this.wait();
                        } catch (InterruptedException ie) {
                            System.out.println("InterruptedException");
                        }
                    }
                }
                if (Thread.interrupted()) {
                    toStop();
                    in.close();
                    out.close();
                    return;
                }
            }
            // 将文件重命名
            in.close();
            out.close();
            if (processFile.renameTo(file)) {
                state = STATE_OK;   // 设置状态为完成
            } else {
                System.out.println("重命名失败!");
            }
        } catch (IOException ioe) {
            toStop();
            System.out.println(this.getClass().getSimpleName() + ":IOException");
        }
    }
    
    private synchronized void makeName() {   // 处理完整的文件保存路径
        int n = 0;
        String url = task.getUrl();
        String filename = AppConfig.getInstance().getSavePath() + 
                "\\" + task.getName().trim() + url.substring(url.lastIndexOf("."));
        File f1 = new File(filename);
        File f2 = new File(filename + "_");
        while (f1.exists() || f2.exists()) {
            n++;
            filename = AppConfig.getInstance().getSavePath() + "\\" + 
                task.getName().trim() + "[" + n + "]" +
                url.substring(url.lastIndexOf("."));
            f1 = new File(filename);
            f2 = new File(filename + "_");
        }
        try {
            f2.createNewFile();
        } catch (Exception exception) {
        }
        file = f1;
    }
    
    /** 开始下载任务 */
    public synchronized void toStart() {
        if (isStopped()) {
            this.start();
        } else if (isPaused()) {
            this.notifyAll();
        }
        this.state = STATE_LOADING;
    }
    
    /** 停下下载任务 */
    public void stopDownload() {
        this.state = STATE_STOPPED;
        this.interrupt();
    }
    
    private synchronized void toStop() {
        this.state = STATE_STOPPED;
    }
    
    public synchronized boolean isStopped() {
        return this.state == STATE_STOPPED ? true : false;
    }
   
    /** 暂停下载任务 */
    public synchronized void toPause() {
        this.state = STATE_PAUSED;
    }
    
    public synchronized boolean isPaused() {
        return this.state == STATE_PAUSED ? true : false;
    }
    
    /** 判断任务是否已经完成 */
    public boolean isOk() {
        return this.state == STATE_OK ? true : false;
    }
    
    // ------------------------------------------------------------
    
    /** 获取下载速度 */
    public int getTimeUsed() {
        return timeUsed;
    }
    
    /** 获取已经读取的字节数(bytes) */
    public int getReadBytes() {
        return readBytes;
    }
    
    /** 获取文件大小字节数(bytes) */
    public int getTotalBytes() {
        return totalBytes;
    }
    
    /** 获取运行速度,单位(k/s) */
    public int getSpeed() {
        if (timeUsed <= 0) return 0;
        speed = readBytes / timeUsed;
        return speed;
    }
    
    /** 获取剩余时间,格式如：hh:mm:ss */
    public String getLeaveTime() {
        if (speed <= 0) return "--:--:--";
        long leaveTime = (totalBytes - readBytes) / speed;
        int temp = (int) (leaveTime / 1000 / 60 / 60);
        String hh;
        if (temp < 9) {
            hh = "0" + temp;
        } else {
            hh = String.valueOf(temp);
        }
        Calendar cal = Calendar.getInstance();
        cal.setTimeInMillis(leaveTime);
        SimpleDateFormat stf = new SimpleDateFormat("mm:ss");
        return (hh + ":" + stf.format(cal.getTime()));
    }
}