testrandomaccessfile.java

流与文件 课件 及 例子 。。。。。。。。。

import java.io.*;

class Student
{
	String name;
	int age;
	final static int LEN = 10;
	public Student(String name,int age)
	{
		if(name.length() > LEN)
		{
			name = name.substring(0,10);
		}
		else
		{
			while(name.length() < LEN)
			{
				name = name + " ";
			}
		}
		this.name = name;
		this.age = age;
	}
}
public class TestRandomAccessFile
{
	public static void main(String[] args) throws Exception
	{
		Student s1 = new Student("AAA",20);
		Student s2 = new Student("BBB",19);
		Student s3 = new Student("CCC",18);
		RandomAccessFile rafrw = new RandomAccessFile("C:\\student.txt","rw");
		rafrw.write(s1.name.getBytes());
		rafrw.writeInt(s1.age);
		rafrw.write(s2.name.getBytes());
		rafrw.writeInt(s2.age);
		rafrw.write(s3.name.getBytes());
		rafrw.writeInt(s3.age);
		
		rafrw.close();
		
		RandomAccessFile rafr = new RandomAccessFile("C:\\student.txt","r");
		int len = 10;
		rafr.seek(len + 4);
		System.out.println("第二个同学：");
		String str = "";
		for(int i = 0;i < len;i++)
		{
			str = str + (char)rafr.readByte();
		}
		System.out.println("name:" + str);
		System.out.println("age:" + rafr.readInt());
		rafr.close();
	}
}