RandomAccessFile 使用示例

<span style="font-size:14px;">package com.wxh.random;

import java.io.*;

public class RandomAccessFileDemo {

	public static void main(String[] args) {
		File source=new File("E:\\test\\source.txt");
		File target=new File("E:\\test\\target.txt");
		
		swip(source,target);
	}

	private static void swip(File source, File target) {
		RandomAccessFile reader=null;
		RandomAccessFile writer=null;
		
		try {
			reader=new RandomAccessFile(source, "r");
			writer=new RandomAccessFile(target,"rw");
			
			//读前半段
			byte[] buf=new byte[100];
			reader.read(buf,0,(int)(source.length()/2));			
			//写入后半段
			writer.setLength(source.length());			
			//指定偏移量
			writer.seek(source.length()/2);
			writer.write(buf, 0, (int)(source.length()/2));
			
			//跳回开头			
			reader.read(buf);
			writer.seek(0);
			writer.write(buf, 0, (int)(source.length()/2));			
			
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			try {
				reader.close();
				writer.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		
		
		
	}

}
</span>