IO流必知必会(17)——writeReplace()实现替换序列化对象

有一种彻底的自定义序列化机制，可以在序列化对象时将该对象替换成其它对象。

public class Person implements Serializable {
    private String name;
    private int age;

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

    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;
    }

    // Override
    private Object writeReplace(){
        ArrayList<Object> list = new ArrayList<Object>();
        list.add(name);
        list.add(age);
        return list;
    }
}

上面的代码重写了writeReplace()方法，Java的序列化机制保证在序列化时先调用该对象的writeReplace方法，如果该方法返回的是另外一个Java对象，则序列化另一个对象。参考下列代码。

public class ReplaceTest {
    public static void main(String[] args) {
        try (ObjectOutputStream oos = new ObjectOutputStream(
                new FileOutputStream("test.txt"));
                ObjectInputStream ois = new ObjectInputStream(
                        new FileInputStream("test.txt"))) {
            Person per = new Person("w", 18);
            oos.writeObject(per);
            ArrayList list = (ArrayList) ois.readObject();
            System.out.println(list);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}