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多线程拷贝文件

发布时间:2022/6/23 23:36:16

 

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以下是一个用多线程拷贝大文件的例子,供大家参考:

package com.wepull.thread;

 

import java.io.*;

 

/**

 * @author leno

 * @version V1.0 利用多线程拷贝文件的类

 */

public class MultiThreadCopy extends Thread {

 

    private File srcFile;// 源文件

    private File tgeFile;// 目标文件

    private int index;// 线程索引号(从0开始)

    private RandomAccessFile rafFrom;// 输入流对象

    private RandomAccessFile rafTo;// 输出流对象

    private static final int MAX_BUF = 10 * 1024 * 1024;// 缓冲区大小

    private int threadNum;// 线程个数

    private long lengthPerThread;// 每个线程需要拷贝的文件长度

    private String threadID;// 自定义线程标识符

    private boolean done = false;

 

    /**

     * @param source

     *            源文件路径

     * @param target

     *            目标文件路径

     * @param index

     *            线程索引号(从0开始)

     * @param threadNum

     *            线程个数

     */

    public MultiThreadCopy(String source, String target, int index,

            int threadNum) {

        this.srcFile = new File(source);

        this.tgeFile = new File(target);

        this.index = index;

        this.threadNum = threadNum;

        this.lengthPerThread = srcFile.length() / threadNum;

        try {

            this.rafFrom = new RandomAccessFile(srcFile, "r");

            this.rafTo = new RandomAccessFile(tgeFile, "rw");

            long pos = lengthPerThread * index;

            rafFrom.seek(pos);

            rafTo.seek(pos);

            this.threadID = "" + index + "线程";

            System.out.println(this.threadID + "开始定位拷贝!");

        } catch (FileNotFoundException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

 

    }

 

    @Override

    public void run() {

        byte[] buf = new byte[MAX_BUF];

        int len = 0;

        long sum = 0;

        try {

            while ((len = rafFrom.read(buf)) != -1 && sum <= lengthPerThread) {

                rafTo.write(buf, 0, len);

                sum += len;

                System.out.println(this.threadID + "拷贝" + len + "字节");

            }

            done = true;

            System.out.println(this.threadID + "拷贝结束!");

        } catch (IOException e) {

            e.printStackTrace();

        } finally {

            try {

                rafFrom.close();

                rafTo.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

    }

 

    public boolean isDone() {

        return done;

    }

 

}

 

package com.wepull.thread;

 

/**

 * @author leno

 * @version V1.0 利用多线程拷贝文件的主线程类

 */

public class MainCopy extends Thread {

 

    private String srcFile;// 源文件

    private String tgeFile;// 目标文件

    private int threadNum;// 线程个数

 

    public MainCopy(String srcFile, String tgeFile, int threadNum) {

        super();

        this.srcFile = srcFile;

        this.tgeFile = tgeFile;

        this.threadNum = threadNum;

    }

 

    public void run() {

        MultiThreadCopy[] mtcs = new MultiThreadCopy[threadNum];

        long t1 = System.currentTimeMillis();

        for (int i = 0; i < mtcs.length; i++) {

            mtcs[i] = new MultiThreadCopy(srcFile, tgeFile, i, mtcs.length);

            mtcs[i].start();

        }

        boolean stop = false;

        // 循环扫描每个线程对象的isDone(),如果所有线程都已经完成,则整个文件拷贝结束

        while (!stop)

            outer: {

                try {

                    Thread.sleep(500);

                } catch (InterruptedException e) {

                    e.printStackTrace();

                }

                for (int i = 0; i < mtcs.length; i++) {

 

                    if (mtcs[i].isDone() == false) {

                        break outer;

                    }

                }

                stop = true;

            }

        long t2 = System.currentTimeMillis();

        System.out.println("整个文件拷贝完毕!大约耗时" + (t2 - t1) + "ms!");

    }

 

}

 

package com.wepull.thread;

 

/**

 * @author leno

 * @version V1.0 利用多线程拷贝文件的测试类

 */

public class TestMultiCopy {

 

    public static void main(String[] args) {

        MainCopy mc = new MainCopy("D://a.exe", "D://b.exe", 4);

        mc.start();

    }

}

 

转载于:https://www.cnblogs.com/CharmingDang/archive/2008/07/28/9663827.html

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