当没有指定默认构造函数时，java序列化如何反序列化最终字段？ [英] How does java serialization deserialize final fields when no default constructor specified?

问题描述

我有一个定义不可变值类型的类，我现在需要序列化。不变性来自构造函数中设置的最终字段。我已经尝试过序列化了，但它确实有效（令人惊讶的是？） - 但我不知道怎么做。

I have an class defining an immutable value type that I now need to serialize. The immutability comes from the final fields which are set in the constructor. I've tried serializing, and it works (surprisingly?) - but I've no idea how.

这是一个类的例子

public class MyValueType implements Serializable
{
    private final int value;

    private transient int derivedValue;

    public MyValueType(int value)
    {
        this.value = value;
        this.derivedValue = derivedValue(value);
    }

    // getters etc...
}

鉴于该类没有没有arg构造函数，如何实例化并设置最终字段？

Given that the class doesn't have a no arg constructor, how can it be instantiated and the final field set?

（旁边 - 我注意到这个类特别是因为IDEA没有为这个类生成no serialVersionUID检查警告，但是成功地为其他类生成了警告'只是使序列化。）

(An aside - I noticed this class particularly because IDEA wasn't generating a "no serialVersionUID" inspection warning for this class, yet successfully generated warnings for other classes that I've just made serializable.)

推荐答案

反序列化由JVM在低于基本语言结构的级别上实现。具体来说，它不会调用任何构造函数。

Deserialization is implemented by the JVM on a level below the basic language constructs. Specifically, it does not call any constructor.

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