fileradaccess.java.bak

Java程序设计培训教程2

import java.io.*;
public class FileRadAccess{
	public static void main(String args[]){
		String readStr,tempStr;
		int fileLine=0;
		long pointerLast1=0,pointerLast2=0;
		try
		{
			RandomAccessFile fileObj1 = new RandomAccessFile("d:\\file\\test.txt","rw");
			while(fileObj1.readLine()!=null)
				fileLine++;
			pointerLast1 = fileObj1.getFilePointer();
			for(int i=0;i<fileLine;i++)
			{
				fileObj1.seek(3*i);
				readStr = fileObj1.readLine();
				System.out.println(readStr);
			}
		}catch(IOException e){
		}
		try
		{
			RandomAccessFile fileObj2 = new RandomAccessFile("d:\\file\\test.txt","rw");
			byte buf[] = new byte[1024];
			String writeStr = new String("*****Hello*****");
			fileObj2.seek(pointerLast1);
			fileObj2.writeBytes(writeStr+"\r\n");
			fileObj2.seek(0);
			fileObj2.readLine();
			fileObj2.readLine();
			pointerLast2 = fileObj2.getFilePointer();
			fileObj2.read(buf);
			tempStr = new String(buf);
			fileObj2.seek(pointerLast2);
			fileObj2.writeBytes(writeStr+"\r\n");
			fileObj2.writeBytes(tempStr);
		}catch(IOException e){
		}
	}
}