15.7 RandomAccessFile

import java.io.RandomAccessFile;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Timer;

public class AppendContent {

    public static void main(String[] args) {
        try {
            //以读、写方式打开一个RandomAccessFile对象
            RandomAccessFile  raf=new RandomAccessFile("C:/Users/Administrator/Desktop/b.txt", "rw");
            {
                //将记录指针移动到out.txt文件的最后
                raf.seek(raf.length());
                SimpleDateFormat df=new SimpleDateFormat("yyyy-mm-dd hh:mm:ss");
                //追加“\r\n”控制换行
                String str=df.format(new Date())+"\r\n";
                raf.write(str.getBytes());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}