HarmonyOS 鸿蒙Next上如何实现安卓的Server-Send Events，和服务端保持长链接，实时接受服务端消息响应

这样试试：

import webSocket from '@ohos.net.webSocket';
import { BusinessError } from '@ohos.base';
let defaultIpAddress = "ws://";
let ws = webSocket.createWebSocket();
ws.on('open', (err:BusinessError, value: Object) => {
  if (err != undefined) {
    console.log(JSON.stringify(err));
    return;
  }
  // 当收到on('open')事件时，可以通过send()方法与服务器进行通信
  ws.send("Hello, server!", (err: BusinessError, value: boolean) => {
    if (!err) {
      console.log("send success");
    } else {
      console.log("send fail, err:" + JSON.stringify(err));
    }
  });
});
ws.on('message',(error: BusinessError, value: string | ArrayBuffer) => {
  console.log("on message, message:" + value);
  // 当收到服务器的`bye`消息时（此消息字段仅为示意，具体字段需要与服务器协商），主动断开连接
  if (value === 'bye') {
    ws.close((err: BusinessError, value: boolean) => {
      if (!err) {
        console.log("close success");
      } else {
        console.log("close fail, err is " + JSON.stringify(err));
      }
    });
  }
});
ws.on('close', (err: BusinessError, value: webSocket.CloseResult) => {
  console.log("on close, code is " + value.code + ", reason is " + value.reason);
});
ws.on('error', (err: BusinessError) => {
  console.log("on error, error:" + JSON.stringify(err));
});
ws.connect(defaultIpAddress, (err: BusinessError, value: boolean) => {
  if (!err) {
    console.log("connect success");
  } else {
    console.log("connect fail, err:" + JSON.stringify(err));
  }
  ws.close((err: BusinessError) => {
    if (!err) {
      console.log("close success");
    } else {
      console.log("close fail, err is " + JSON.stringify(err));
    }
  });
});