/**
* 实现文件复制功能
* 多线程实现文件从一个目录复制到另一个目录
* @param sourceFile:给定源文件路径名
* @param desPath:复制点文件路径
* @return
*/
代码实现如下:
package com.tulun.thread;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.RandomAccessFile;
/**
* 多线程复制文件
*/
public class ThreadCopyFile {
public static void main(String[] args) throws Exception {
File file = new File("D:\\demo\\erke\\test.txt");
startThread(5, file.length(), "D:\\demo\\erke\\test.txt",
"D:\\demo\\erke\\test1.txt");
}
/**
* 开启多线程复制
*
* @param threadnum 线程数
*
* @param fileLength 文件大小(用于确认每个线程下载多少东西)
*
* @param sourseFilePath 源文件目录
*
* @param desFilePath 目标文件目录
*
*/
public static void startThread(int threadnum, long fileLength, String sourseFilePath, String desFilePath) {
System.out.println(fileLength);
long modLength = fileLength % threadnum;
System.out.println("modLength:" + modLength);
long desLength = fileLength / threadnum;
System.out.println("desLength:" + desLength);
for (int i = 0; i < threadnum; i++) {
System.out.println((desLength * i) + "-----" + (desLength * (i + 1)));
new FileWriteThread((desLength * i), (desLength * (i + 1)), sourseFilePath, desFilePath).start();
}
if (modLength != 0) {
System.out.println("最后的文件写入");
System.out.println((desLength * threadnum) + "-----" + (desLength * threadnum + modLength));
new FileWriteThread((desLength * threadnum), desLength * threadnum + modLength + 1, sourseFilePath,
desFilePath).start();
}
}
/**
* 写线程:指定文件开始位置、目标位置、源文件、目标文件,
*/
static class FileWriteThread extends Thread {
private long begin;
private long end;
private RandomAccessFile sourseFile;
private RandomAccessFile desFile;
public FileWriteThread(long begin, long end, String sourseFilePath, String desFilePath) {
this.begin = begin;
this.end = end;
try {
this.sourseFile = new RandomAccessFile(sourseFilePath, "rw");
this.desFile = new RandomAccessFile(desFilePath, "rw");
} catch (FileNotFoundException e) {
}
}
public void run() {
try {
sourseFile.seek(begin);
desFile.seek(begin);
int hasRead = 0;
byte[] buffer = new byte[1];
while (begin < end && -1 != (hasRead = sourseFile.read(buffer))) {
begin += hasRead;
desFile.write(buffer, 0, hasRead);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
sourseFile.close();
desFile.close();
} catch (Exception e) {
}
}
}
}
}
运行结果: