Java基础ObjectOutputStream、ObjectInputStream

package com.hspedu.io_;

import org.junit.Test;

import java.io.*;

public class TestSaveObjectFile {
    // ObjectOutputStream保存对象、ObjectInputStream读取对象
    @Test
    public void saveObjByObjectOutputStream() throws IOException {
        String savePath = "e:\\JavaIO\\ObjectOutputStream\\data.dat";
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream(savePath));

        objectOutputStream.writeInt(10);

        objectOutputStream.writeUTF("hello, world!");

        objectOutputStream.writeDouble(20.5);

        objectOutputStream.writeBoolean(true);

        Cat cat = new Cat("小白", 3);
        objectOutputStream.writeObject(cat);

        objectOutputStream.close();
        System.out.println("保存完毕");
    }

    @Test
    public void readObjByObjectInputStream() throws IOException, ClassNotFoundException {
        String readPath = "e:\\JavaIO\\ObjectOutputStream\\data.dat";
        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(readPath));

        int i = objectInputStream.readInt();
        System.out.println("i = " + i);

        String s = objectInputStream.readUTF();
        System.out.println("s = " + s);

        double d = objectInputStream.readDouble();
        System.out.println("d = " + d);

        boolean b = objectInputStream.readBoolean();
        System.out.println("b = " + b);

        Object object = objectInputStream.readObject();
        System.out.println(object + "的运行类型是：" + object.getClass());
        Cat cat = (Cat) object; // 转换编译类型为Cat，调用eatFish方法
        cat.eatFish();

        objectInputStream.close();
    }
}

class Cat implements Serializable {
    private String name;
    private int age;

    public Cat(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return "Cat{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public void eatFish() {
        System.out.println("猫吃鱼..");
    }
}

注意：1、ObjectOutputStream保存的对象，其类必须实现(implements) Serializable接口；2、ObjectInputStream读取对象信息的顺序必须要保存对象的顺序一致