HarmonyOS 使用class-transformer和@Expose注解在嵌套对象场景下，如何实现序列化与反序列化。

1、下载class-transform

ohpm install class-transformer 
ohpm install reflect-metadata 

2、导入包

import { classToPlain, Expose, plainToClass } from 'class-transformer'; 
import 'reflect-metadata'; 

3、编写代码

class MyClass {
  @Expose({ name: 'auth-type' })
  authType: number = 1;
  meta: AuthorMeta = new AuthorMeta();
}

class AuthorMeta {
  @Expose({ name: 'focus_count' })
  focusCount: number = 0;
}

4、测试

import { classToPlain, Expose, plainToClass } from 'class-transformer';
import 'reflect-metadata';

@Entry
@Component
struct Test6 {
  build() {
    Column(){
      Button('验证1').onClick((event: ClickEvent) => {
        let myClass: MyClass = new MyClass();
        myClass.authType = 1;

        let serializedData = classToPlain(myClass);
        let jsonStr: string = JSON.stringify(serializedData)
        console.log(jsonStr);

        let myClass1: MyClass = JSON.parse(jsonStr)
        let myDataObject = plainToClass(MyClass, myClass1);
        console.log("authType is " + myDataObject.authType);
        let myAuthMeta = plainToClass(AuthorMeta, myDataObject.meta)
        console.log("focusCount is " + myAuthMeta.focusCount);
      })
      Button('验证2').onClick((event: ClickEvent) => {
        let result = plainToClass(MyClass, JSON.parse("{\"auth-type\":3,\"meta\":{\"focus_count\":333}}"))
        let result1 = plainToClass(AuthorMeta, result.meta)
        console.log("focusCount is "+result1.focusCount);
      })
    }
  }
}

class MyClass {
  @Expose({ name: 'auth-type' })
  authType: number = 1;
  meta: AuthorMeta = new AuthorMeta();
}

class AuthorMeta {
  @Expose({ name: 'focus_count' })
  focusCount: number = 0;
}