RandomAccesssFileTest

package com.yd.wmsc.util;

import java.io.IOException;
import java.io.RandomAccessFile;

public class RandomAccesssFileTest {
    public static void main(String[] args) {
        RandomAccessFile r = null ;
        try {
             r = new RandomAccessFile("D:/heihei.txt", "rw");

                r.writeChar('a');
                System.out.println(r.getFilePointer());//
                r.writeChar('b');
                r.writeChar('c');
                System.out.println(r.getFilePointer());//6
                //abc

                r.seek(2);
                r.writeChar('d'); //adc

                StringBuffer strBuf = new StringBuffer();
                r.seek(0); //指针归回初始位置
                long length = r.length()/2;
                System.out.println(length);
                for (long i = 0L; i < length; i++) {
                     strBuf.append(r.readChar());
                }

                System.out.println(strBuf); //结果是adc
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                r.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

}}