Serializable：readResolve

最新推荐文章于 2024-04-01 20:14:27 发布

原创最新推荐文章于 2024-04-01 20:14:27 发布 · 892 阅读

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#序列化

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本文详细解释了序列化类中readResolve()方法的作用，当该方法被调用时，序列化过程会直接返回readResolve()方法返回的对象，而忽略readObject的实现。并通过实例代码演示了这一特性。

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如果序列化类定义了Object readResolve() ，那么将无视readObject的实现，直接返回作为readResolve() 方法返回值的对象。

public class People implements Serializable
{
    /**
     * 
     */
    private static final long serialVersionUID = 2659082826995480601L;
    private int age;
    private String name;

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

    public int getAge() {
        return age;
    }

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

    public String getName() {
        return name;
    }

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

    private void writeObject(ObjectOutputStream out)
    {
        System.out.println("是否调用了我？");
    }
    private void readObject(ObjectInputStream in)
    {
        System.out.println("是否调用了我？");
    }

    private Object readResolve() 
    {
        return new People(20,"老子喜欢刚正面");
    }

}

测试程序：

@Test
public void testOut01() throws FileNotFoundException, IOException
{
    People p = new People(100,"老汉");
    ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("D:\\temp01.txt"));
    out.writeObject(p);
    out.flush();
    out.close();
}

@Test
public void testIn01() throws FileNotFoundException, IOException, ClassNotFoundException
{
    ObjectInputStream in = new ObjectInputStream(new FileInputStream("D:\\temp01.txt"));
    People p = (People)in.readObject();
    in.close();
    System.out.println(p.getAge());
    System.out.println(p.getName());

}

People p = (People)in.readObject();拿到了

private Object readResolve() 
{
    return new People(20,"老子喜欢刚正面");
}

这个对象，尽管writeObject/readObject什么都没做。
在这个过程中writeObject/readObject仍然在序列话和反序列化过程中被调用。