HarmonyOS鸿蒙Next中json序列化 json解析 序列化反序列化丢失方法问题

1.安装插件

ohpm install class-transformer
ohpm install reflect-metadata

2.使用方法

p = plainToClass(Props,p)

import { JSON } from '@kit.ArkTS';
import { promptAction } from '@kit.ArkUI';
import { plainToClass } from 'class-transformer';

class Props {
  public name: string;
  public age: number;
  constructor(name: string, age: number) {
    this.name = name;
    this.age = age;
  }
  toString(): string {
    promptAction.showToast({
      message: `name:${this.name},age:${this.age}`,
      duration: 2000
    });
    return `name:${this.name},age:${this.age}`;
  }
}

@Entry
@Component
struct StartCameraPickerView {

  build() {
    Column() {

      Button("序列化反序列化")
        .onClick(() => {
          let props:Props = new Props("张三", 18);
          let jsonData:string = JSON.stringify(props);
          let p = JSON.parse(jsonData) as Props;
          p = plainToClass(Props,p)
          p.toString()
        })
    }
    .width("100%")
    .height("100%")
    .justifyContent(FlexAlign.Center)
    .alignItems(HorizontalAlign.Center)
  }
}

将Map转换为JSON字符串

let mapSource = new Map<string, string>(); 
mapSource.set('name', 'name1'); 
mapSource.set('width', '100'); 
mapSource.set('height', '50'); 

let jsonObject: Record<string, Object> = {}; 
mapSource.forEach((value, key) => { 
  if (key !== undefined && value !== undefined) { 
    jsonObject[key] = value; 
  } 
}) 
let jsonInfo: string = JSON.stringify(jsonObject); 

@Entry 
@Component 
struct Index { 
  build() { 
    Column() { 
      Button('Map to JSON') 
        .onClick(() => { 
          console.log('jsonInfo:', jsonInfo); // jsonInfo: {"name":"name1","width":"100","height":"50"} 
        }) 
    } 
  } 
}

json转Record

//json转object

  let jsonRecord: Record<string, Object> = JSON.parse(info) as Record<string, Object>;

  console.log("json转object:" + jsonRecord)

json转map

import { HashMap } from '@kit.ArkTS'; 

let str: string = '{"common_params": {' + 
  '"city_id": 1,' + 
  '"nav_id_list": "",' + 
  '"show_hook_card": 2,' + 
  '"use_one_stop_structure": 1,' + 
  '"version_tag": "homepageonestop"' + 
  '}' + 
  '}'; 

let jsonObj: Object = JSON.parse(str); 
let commObj = (jsonObj as Record<string, Object>); 
let commRecord = (commObj['common_params'] as Record<string, Object>); 
let keyStr = Object.keys(commRecord); 

for (let index: number = 0; index < keyStr.length; index++) { 
  commRecord[keyStr[index].toString()].toString(); 
} 

let hashMapData: HashMap<string, Object> = new HashMap(); 
hashMapData.set('common_params', commRecord); 

@Entry 
@Component 
struct Index { 
  build() { 
    Row() { 
      Column() { 
        Button('JSON to HashMap') 
          .onClick(() => { 
            // common_params: {"city_id":1,"nav_id_list":"","show_hook_card":2,"use_one_stop_structure":1,"version_tag":"homepageonestop"} 
            console.log('common_params:', JSON.stringify(hashMapData.get('common_params'))); 
          }) 
      } 
      .width('100%') 
    } 
    .height('100%') 
  } 
}

json转部分属性

let jsonStr2 = JSON.stringify(obj, ['name']);

反序列化number类型丢失精度

https://developer.huawei.com/consumer/cn/doc/harmonyos-faqs-V5/faqs-arkts-129-V5

import { JSON } from '@kit.ArkTS';

@Entry
@Component
struct Index {
  @State str: string = 'bigint num';

  build() {
    Row() {
      Column() {
        Button(this.str)
          .onClick(() => {
            let numberText = '{"largeNumber":1122333444455556666677777888889}';
            let numberObj = JSON.parse(numberText, undefined, {
              bigIntMode: JSON.BigIntMode.PARSE_AS_BIGINT,
            }) as Object;
            let numberObj2 = JSON.parse(numberText) as Object;
            console.info((numberObj as object)?.["largeNumber"]); // 1122333444455556666677777888889
            console.info((numberObj2 as object)?.["largeNumber"]); // 1.1223334444555567e+30
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}