HarmonyOS 怎么监听网络断网和网络重新连接

监听网络推荐使用netConnect，参考demo如下参考文档：

https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/net-connection-manager-V5

import connection from '@ohos.net.connection';
import { BusinessError } from "@ohos.base";
import { hilog } from '@kit.PerformanceAnalysisKit';
@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  onPageShow(): void {
    this.init();
  }

  init(){
    let netCon: connection.NetConnection = connection.createNetConnection();
    netCon.register((error: BusinessError) => {
      if(error==undefined){
        hilog.info(0x0000,"网络状态","注册成功")
      }else {
        hilog.info(0x0000,"网络状态","注册失败 error is %s",JSON.stringify(error))
      }


    });

    // 订阅网络可用事件。调用register后，才能接收到此事件通知
    netCon.on('netAvailable', (data: connection.NetHandle) => {
      hilog.info(0x0000,"网络状态",'网络状态可用 ' + JSON.stringify(data));
    });
    // 订阅网络不可用事件。调用register后，才能接收到此事件通知
    netCon.on('netUnavailable', () => {
      hilog.info(0x0000,"网络状态",'网络状态不可用1 ');
    });
    netCon.on('netLost', () => {
      hilog.info(0x0000,"网络状态",'网络状态不可用2 ');
    });

    // 订阅网络连接信息变化事件。调用register后，才能接收到此事件通知
    netCon.on('netConnectionPropertiesChange', (data: connection.NetConnectionPropertyInfo) => {
      hilog.info(0x0000,"网络状态","Succeeded to get data: " + JSON.stringify(data));
    });

    connection.getDefaultNet().then((netHandle)=>{
      connection.reportNetDisconnected(netHandle).then(()=> {
        hilog.info(0x0000,"网络状态",'reportNetDisconnected ');
      });
    });

  }

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
      }
      .width('100%')
    }
    .height('100%')
  }
}