java io之RandomAccessFile的用法

 Employee.java
 1 package com.io;

public class Employee {

    private String name;
    
    private int age;
    
    private static final int LEN = 8;
    
    public Employee(String name, int age) {
        super();
        if (name.length() > LEN) {
            name = name.substring(0, LEN);
        } else {
            while (name.length()<LEN) {
                name += "\u0000";
            }
        }
        this.age = age;
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }    
    
    
    
    
}

RamdomFileTest.java

package com.io;

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

public class RamdomFileTest {
    
    public static void main(String[] args) throws IOException {
        Employee e1 = new Employee("zhangsan",23);
        Employee e2 = new Employee("lisi",24);
        Employee e3 = new Employee("wangwu",25);
        
        RandomAccessFile ra = new RandomAccessFile("f:\\1.txt","rw");
        ra.write(e1.getName().getBytes());
        ra.writeInt(e1.getAge());
        ra.write(e2.getName().getBytes());
        ra.writeInt(e2.getAge());
        ra.write(e3.getName().getBytes());
        ra.writeInt(e3.getAge());
        ra.close();
        
        RandomAccessFile raf = new RandomAccessFile("f:\\1.txt","r");
        int len = 8;
        raf.skipBytes(12);
        System.out.println("第二个员工的信息：");
        String str = "";
        for (int i = 0; i < len; i++) {
            str = str+ (char)raf.readByte();
        }
        System.out.println("name:"+str);
        System.out.println("age:"+raf.readInt());
        
        System.out.println("第一个员工的信息：");
        raf.seek(0);
        str = "";
        for (int i = 0; i < len; i++) {
            str = str + (char)raf.readByte();
        }
        System.out.println("name:"+str);
        System.out.println("age:"+raf.readInt());
        
        System.out.println("第三个员工的信息：");
        raf.skipBytes(12);
        str = "";
        for (int i = 0; i < len; i++) {
            str = str + (char)raf.readByte();
        }
        System.out.println("name:"+str);
        System.out.println("age:"+raf.readInt());
        
        System.out.println("程序执行完毕...");
    }
}

打印结果：

第二个员工的信息：
name:lisi

age:24
第一个员工的信息：

name:zhangsan
age:23
第三个员工的信息：
name:wangwu

age:25
程序执行完毕...