切割文件(任何文件)，并拼接

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/myloveprogrmming/article/details/82871117

1.分割：
 

package a;

import java.io.*;
//用三个线程把文件切割成三段
class PartOne implements Runnable{
	File f;
	int size;
	PartOne(File f,int size)
	{
		this.f=f;
		this.size=size;
	}
	public void run()
	{
		BufferedInputStream bin = null;;
		BufferedOutputStream bout=null;
		try {
			bin=new BufferedInputStream(new FileInputStream(f));
			bout=new BufferedOutputStream(new FileOutputStream("d:\\part1.rmvb"));
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		for(int i=1;i<=size/3;i++)
		{
			try {
				bout.write(bin.read());
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		try {
			bout.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		try {
			bin.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

class PartTwo implements Runnable{
	File f;
	int size;
	PartTwo(File f,int size)
	{
		this.f=f;
		this.size=size;
	}	
	public void run()
	{
		BufferedInputStream bin = null;;
		BufferedOutputStream bout=null;
		try {
			bin=new BufferedInputStream(new FileInputStream(f));
			bout=new BufferedOutputStream(new FileOutputStream("d:\\part2.rmvb"));
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
			bin.skip(size/3);
	
		for(int i=1;i<=size/3;i++)
		{
			try {
				bout.write(bin.read());
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		try {
			bout.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		try {
			bin.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}
class PartThree implements Runnable{
	File f;
	int size;
	PartThree(File f,int size)
	{
		this.f=f;
		this.size=size;
	}	
	public void run()
	{
		BufferedInputStream bin = null;;
		BufferedOutputStream bout=null;
		try {
			bin=new BufferedInputStream(new FileInputStream(f));
			bout=new BufferedOutputStream(new FileOutputStream("d:\\part3.rmvb"));
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		try {
			bin.skip((size/3)*2);
		} catch (IOException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
		int len=size-(size/3)*2;
		for(int i=1;i<=len;i++)
		{
			try {
				bout.write(bin.read());
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		try {
			bout.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		try {
			bin.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
}
public class Homework1 {

	public static void main(String[] args) throws IOException, IOException {
		File f=new File("E:\\迅雷下载\\伯德小姐.rmvb");
		int fsize=new FileInputStream(f).available();
		Thread t1=new Thread(new PartOne(f,fsize));
		t1.start();
		Thread t2=new Thread(new PartTwo(f,fsize));
		t2.start();
		Thread t3=new Thread(new PartThree(f,fsize));
		t3.start();
	}

}

2.拼接（还原）

package a;

import java.io.*;

public class HomeTest {

	public static void main(String[] args) throws IOException {
		BufferedInputStream bin1=new BufferedInputStream(new FileInputStream("d:\\part1.rmvb")); 
		BufferedInputStream bin2=new BufferedInputStream(new FileInputStream("d:\\part2.rmvb")); 
		BufferedInputStream bin3=new BufferedInputStream(new FileInputStream("d:\\part3.rmvb")); 
		BufferedOutputStream bout=new BufferedOutputStream(new FileOutputStream("d:\\haha.rmvb"));
		byte[] b=new byte[1024];
		int len=0;
		while((len=bin1.read(b))!=-1) {
			bout.write(b,0,len);
		}
		
		while((len=bin2.read(b))!=-1) {
			bout.write(b,0,len);
		}
		
		while((len=bin3.read(b))!=-1) {
			bout.write(b,0,len);
		}
		bout.close();
		bin3.close();
		bin2.close();
		bin1.close();
		
	}

}