Kryo官方文档学习笔记

Posted 2021-09-22 儒雅随和狗粉丝

一.官方文档

Kryo目前更新到5.0版本: https://github.com/EsotericSoftware/kryo

4.0版本中文翻译: https://blog.csdn.net/fanjunjaden/article/details/72823866?utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-12.control&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-12.control

4.0版本和5.0版本的文档差距比较大,5.0要讲解的详细很多，建议还是看5.0

二.学习笔记

1.Round trip

这段代码的意思是没有经过流进行传输序列化后的对象，而是将序列化后的字节直接存储在buffer字节数组中,也就是序列化到字节并返回到对象

Kryo kryo = new Kryo();

// Register all classes to be serialized.
kryo.register(SomeClass.class);

SomeClass object1 = new SomeClass();

Output output = new Output(1024, -1);
kryo.writeObject(output, object1);

Input input = new Input(output.getBuffer(), 0, output.position()); 
SomeClass object2 = kryo.readObject(input, SomeClass.class);
 
// output.getBuffer()直接在buffer数组里取出字节序列

源码:
public Output(int bufferSize, int maxBufferSize) {
        this.varEncoding = true;
        if (bufferSize > maxBufferSize && maxBufferSize != -1) {
            throw new IllegalArgumentException("bufferSize: " + bufferSize + " cannot be greater than maxBufferSize: " + maxBufferSize);
        } else if (maxBufferSize < -1) {
            throw new IllegalArgumentException("maxBufferSize cannot be < -1: " + maxBufferSize);
        } else {
            this.capacity = bufferSize;
            this.maxCapacity = maxBufferSize == -1 ? 2147483639 : maxBufferSize;
            this.buffer = new byte[bufferSize]; // 存储在buffer不经过流
        } 
    }

2.Deep and shallow copies

用来代替上面的Round trip

即：Kryo 支持使用从一个对象到另一个对象的直接赋值来制作对象的深拷贝和浅拷贝。这比序列化为字节并返回对象更有效

Kryo kryo = new Kryo();
SomeClass object = ...
SomeClass copy1 = kryo.copy(object);
SomeClass copy2 = kryo.copyShallow(object);

3.补充的一些知识

https://my.oschina.net/u/725800/blog/823467