本篇分享一下 HarmonyOS 中的Socket使用方法

將從2個方面實踐：

1. HarmonyOS 手機應(yīng)用連接PC端 SocketServer
2. HarmonyOS 手機應(yīng)用連接MQTT 服務(wù)端

通過循序漸進的方式，全面了解實踐HarmonyOS中的Socket用法

學(xué)習(xí)本章前先熟悉文檔開發(fā)知識更新庫gitee.com/li-shizhen-skin/harmony-os/blob/master/README.md前往。

注意 ：編譯時IDE會給出如下警告提示，@ohos.net.socket 這個包沒有驗證過。

或者+mau123789熟悉文檔是v喔！

Currently module for '@ohos.net.socket' is not verified. If you're importing napi, its verification will be enabled in later SDK version. Please make sure the corresponding .d.ts file is provided and the napis are correctly declared.

官方文檔說明

引入Socket包

import socket from '@ohos.net.socket';

創(chuàng)建TCPSocket，連接遠端服務(wù)器

//注意，這里聲明變量tcp, 建議將類型加上，否則不利于IDE聯(lián)想API
let tcp: socket.TCPSocket = socket.constructTCPSocketInstance();

let bindAddress = {
  address: '192.168.xx.xx',
  port: x
};

let connectAddress = {
  address: '192.168.xx.xx',
  port: x
};

//1. 綁定本機地址和端口
tcp.bind(bindAddress, err = > {

  if(err){
    console.log('1-' + JSON.stringify(err))
    return
  }

  //2. 連接遠端服務(wù)器
  tcp.connect({
    address: connectAddress,
    timeout: 30000
  }).then( r = > {
    console.log('2-' +JSON.stringify(r))
  }).catch((e) = > {
    console.log('3-' + JSON.stringify(e))
  })

})
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狀態(tài)監(jiān)聽

訂閱“連接”

tcp.on('connect', () = > {
    
});
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解除“連接”訂閱

tcp.off('connect', () = > {
    
});
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訂閱“消息”

tcp.on('message', () = > {
    //即：可以在這里隨時接收到服務(wù)端發(fā)送過來的消息
});
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解除“消息”訂閱

tcp.off('message', () = > {
   
});
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發(fā)送消息

let msg: string = '我是HarmonyOS客戶端'

tcp.send({data: msg}, (error)= >{
  if(error) {
    console.log('消息沒有發(fā)送成功： ' + JSON.stringify(error))
  } else {
    console.log('消息發(fā)送成功')
  }
})
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實踐：實現(xiàn)Socket與ServerSocket通信

創(chuàng)建ServerSocket 服務(wù)

這里使用IntelliJ IDEA創(chuàng)建一個Java工程，然后運行在自己電腦上即可使用

如果你實在沒法自己實現(xiàn)ServerSocket，可以在網(wǎng)上找一個調(diào)試Socket的工具

監(jiān)聽客戶端接入

package com.harvey.socketserver;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class Main {

    public static void main(String[] args) {
            try {
                ServerSocket serverSocket = new ServerSocket(6666);

                //一. 建立客戶端監(jiān)聽
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        while (true){
                            try {
                                Socket clientSocket = serverSocket.accept();

                                System.out.println("客戶端:" + clientSocket.getInetAddress().getLocalHost()+"已連接到服務(wù)器");

                                new Server(clientSocket).start();

                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                            try {
                                Thread.sleep(1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }).start();

            } catch (IOException e) {
                e.printStackTrace();
            }
    }

}
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監(jiān)聽客戶端消息且自動回復(fù)

package com.harvey.socketserver;

import java.io.*;
import java.net.Socket;

public class Server extends Thread{

    Socket clientSocket;
    InputStream is;
    OutputStream os;
    String lastReceiverMessage;

    int LIVE_TIME = 60*1000;

    public Server(Socket clientSocket){
        this.clientSocket = clientSocket;
        try {
            is = this.clientSocket.getInputStream();
            os = this.clientSocket.getOutputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {

        while(LIVE_TIME != 0){

            if ( this.clientSocket != null ) {

                if ( this.clientSocket.isClosed() || this.clientSocket.isInputShutdown() || this.clientSocket.isOutputShutdown()) {
                    LIVE_TIME = 0;
                } else {
                    readMessage();

                    responseMessage();

                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    LIVE_TIME -= 1000;
                }

            } else {
                LIVE_TIME = 0;
            }

        }

        closeAllChannel();

    }

    //釋放資源
    private void closeAllChannel(){
        try {
            if(clientSocket != null){
                clientSocket.close();
                clientSocket = null;
            }
            if(is != null){
                is.close();
                is = null;
            }
            if(os != null){
                os.close();
                os = null;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //讀取客戶端消息， 注意：這里是為了省事，用的readLine接口
    //如果消息中有換行符，則會丟失消息
    private void readMessage(){

        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        try {
            lastReceiverMessage  = br.readLine();
            System.out.println("已接收到端消息：【" + lastReceiverMessage +"】");
        } catch (IOException e) {
            System.err.println("接收消息失敗:" + e.getMessage());
        }

    }

    //自動回復(fù)客戶端消息
    private void responseMessage(){
        try {
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
            bw.write(System.currentTimeMillis() + "親愛的客戶端，已收到您的來信。"  +  lastReceiverMessage + "n");
            bw.flush();
            System.out.println("回復(fù)消息成功");
        } catch (IOException e) {
            System.err.println("回復(fù)消息失敗:" + e.getMessage());
        }

    }

}
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創(chuàng)建客戶端應(yīng)用

布局

為了驗證Socket，交互頁面包含如下功能：

1. 連接/斷開
2. 渲染接收到的消息
3. 渲染已發(fā)送的消息
4. 文字輸入
5. 消息發(fā)送

HarmonyOS 核心代碼

import socket from '@ohos.net.socket'
import util from '@ohos.util';
import Prompt from '@system.prompt';

let tcpSocket: socket.TCPSocket = null

@Entry
@Component
struct SocketPage {

  @State isConnected: boolean = false
  
  @State sendMessage: string = ''
  @State inputMessage: string = ''
  @State receiveMessage: string = ''

  @State connectButtonBGColor: Color = Color.Gray
  @State connectButtonTextColor: Color = Color.White

  //頁面創(chuàng)建時，注冊自定義消息，監(jiān)聽來消息和連接狀態(tài)
  aboutToAppear(){

    getContext().eventHub.on('remotemsg', (value)= >{
        this.receiveMessage = value
    })

    getContext().eventHub.on('connectStatus', (value)= >{
        if(value === 'connect'){
          this.connectButtonBGColor = Color.Green
        } else if(value === 'close'){
          this.connectButtonBGColor = Color.Gray
        }
    })

  }

  //頁面銷毀時，解除所有訂閱，關(guān)閉socket
  aboutToDisappear() {
     tcpSocket.off("message")
     tcpSocket.off("connect")
     tcpSocket.off("close")
     tcpSocket.close()
     tcpSocket = null
  }
  build(){

        Column( {space: 20} ){

          Row( {space: 20} ){
            Button('連接').width(60).height(60).fontSize(12)
              .backgroundColor(this.connectButtonBGColor)
              .fontColor(this.connectButtonTextColor)
              .onClick( ()= > {
                
                if(this.isConnected){
                  tcpSocket.close()
                } else {
                  connectServer()
                }
                
              })
          }

          Column({space: 30}){
            Text('發(fā)送：' + this.sendMessage).fontSize(20).width('100%')
            Text('接收：' + this.receiveMessage).fontSize(20).width('100%')
          }.backgroundColor(Color.Pink)
          .padding( { top: 20, bottom: 20} )

          Row({space: 10}) {
            TextArea({placeholder: '輸入文字', text: this.inputMessage})
              .onChange( (value) = > {
                this.inputMessage = value
              })
              .fontSize(20)
              .width('75%')

            Button('發(fā)送').fontColor(29).onClick( () = > {
              sendMessage(this.inputMessage)
              this.sendMessage = this.inputMessage
              this.inputMessage = ''
            }).width('20%')
          }
          .width('100%')
          .justifyContent(FlexAlign.Center)

        }
        .width('100%')
        .height('100%')
        .alignItems(HorizontalAlign.Start)
        .justifyContent(FlexAlign.Start)
        .padding({top: px2vp(120)})

  }
}


//發(fā)送消息
function sendMessage(msg: string){
  if(tcpSocket){
    tcpSocket.send({data: msg + 'n'}, (error)= >{
      if(error) {
        console.log('消息沒有發(fā)送成功： ' + JSON.stringify(error))
      } else {

        getContext().eventHub.emit('')
        console.log('消息發(fā)送成功')
      }
    })
  } else {
    Prompt.showToast({message: '還沒有連接服務(wù)器'})
  }
}

//開始連接服務(wù)器
function connectServer(){

  let bindAddress = {
    address: '192.168.71.66',
    port: 1983,
    family: 1
  };

  let connectAddress = {
    address: '192.168.71.23',
    port: 6666 //端口號要和ServerSocket 一致
  };

  tcpSocket = socket.constructTCPSocketInstance()

  tcpSocket.on('close', () = > {
    console.log("on close")
    getContext().eventHub.emit('connectStatus', 'close')
  });

  tcpSocket.on('connect', () = > {
      console.log("on connect")
      getContext().eventHub.emit('connectStatus', 'connect')
  });

  tcpSocket.on('message' , ( value: {message: ArrayBuffer, remoteInfo: socket.SocketRemoteInfo} ) = > {

    let view = new Uint8Array(value.message);
    let textDecoder = util.TextDecoder.create()
    let str = textDecoder.decodeWithStream(view);

    getContext().eventHub.emit('remotemsg', str)
  })


  tcpSocket.bind(bindAddress, err = > {

    if(err){
      console.log('1-' + JSON.stringify(err))
      return
    }

    tcpSocket.connect({
      address: connectAddress,
      timeout: 30000
    }).then( r = > {
      console.log('2-' +JSON.stringify(r))
    }).catch((e) = > {
      console.log('3-' + JSON.stringify(e))
    })

  })

}
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最終效果

實踐：實現(xiàn)MQTT連接

準備MQTT Broker

MQTT使用的是 mosquitto，官網(wǎng)下載地址

關(guān)于MQTT的入門使用，可參見“MQTT試用”

注意：mosquitto 安裝完成后，需要打開匿名設(shè)置，并且監(jiān)聽自己電腦的IP和1883端口 mosquitto的配置文件名：mosquitto.conf

• allow_anonymous true
• listener 1883 192.168.xxx.xxx

MQTT 5.0 網(wǎng)址

https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.pdf

1. 熟悉 “3.1 CONNECT – Connection Request”
2. 熟悉 “3.2 CONNACK – Connect acknowledgement”

場景模擬

客戶端使用Socket 連接mosquitto, 并且響應(yīng)連接ACK

代碼實現(xiàn)

請求連接

這部分需要分為兩步：1. Socket連接 2. MQTT連接請求（即發(fā)送連接請求命令）

a. Socket連接

function connectMQTTServer(){

  let bindAddress = {
    address: '192.168.71.66',
    port: 1983,
    family: 1
  };

  let connectAddress = {
    address: '192.168.71.23', //MQTT服務(wù)器IP
    port: 1883 //MQTT服務(wù)器端口
  };

  tcpSocket = socket.constructTCPSocketInstance()

  listenerStatus()

  tcpSocket.bind(bindAddress, err = > {

    if(err){
      console.log('1-' + JSON.stringify(err))
      return
    }

    tcpSocket.connect({
      address: connectAddress,
      timeout: 30000
    }).then( r = > {
      console.log('2-' +JSON.stringify(r))
    }).catch((e) = > {
      console.log('3-' + JSON.stringify(e))
    })

  })
}
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b. MQTT連接請求

tcpSocket.on('connect', () = > {
  console.log("on connect")

   //拼接MQTT請求數(shù)據(jù)
  let connectCMD = MQTTConnect.getFixHeader()

  //發(fā)送MQTT連接請求命令
  tcpSocket.send({data: connectCMD.buffer}, (error)= >{
    if(error) {
      console.log('消息沒有發(fā)送成功： ' + JSON.stringify(error))
    } else {
      console.log('消息發(fā)送成功')
    }
  })

  getContext().eventHub.emit('connectStatus', 'connect')
});
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構(gòu)建MQTT請求連接數(shù)據(jù)

代碼有點枯燥，都是要對著MQTT 5.0規(guī)范文檔來實現(xiàn)的

import util from '@ohos.util'

export default class MQTTConnect{

  //3.1.1 CONNECT Fixed Header 【2字節(jié)】
  //3.1.2 CONNECT Variable Header
      //3.1.2.1 Protocol Name 【6字節(jié)】
      //3.1.2.2 Protocol Version 【1字節(jié)】
      //3.1.2.3 Connect Flags 【1字節(jié)】
      //3.1.2.10 Keep Alive 【2字節(jié)】
      //3.1.2.11 CONNECT Properties
          //3.1.2.11.1 Property Length 【1字節(jié)】
          //3.1.2.11.2 Session Expiry Interval 【4字節(jié)】
          //3.1.2.11.3 Receive Maximum 【2字節(jié)】
          //3.1.2.11.4 Maximum Packet Size 【4字節(jié)】
          //3.1.2.11.5 Topic Alias Maximum 【2字節(jié)】
          //3.1.2.11.6 Request Response Information 【1字節(jié)】
          //3.1.2.11.7 Request Problem Information 【1字節(jié)】
          //3.1.2.11.8 User Property【UTF-8 String Pair】
          //3.1.2.11.9 Authentication Method 【UTF-8 String】
          //3.1.2.11.10 Authentication Data【Binary Data】
  //3.1.3 CONNECT Payload
      //3.1.3.1 Client Identifier (ClientID) 【UTF-8 String】
      //3.1.3.2 Will Properties
          //3.1.3.2.1 Property Length 【Variable Byte Integer】
          //3.1.3.2.2 Will Delay Interval 【4字節(jié)】
          //3.1.3.2.3 Payload Format Indicator 【1字節(jié)】
          //3.1.3.2.4 Message Expiry Interval 【4字節(jié)】
          //3.1.3.2.5 Content Type【UTF-8 String】
          //3.1.3.2.6 Response Topic【UTF-8 String】
          //3.1.3.2.7 Correlation Data 【Binary Data】
          //3.1.3.2.8 User Property【UTF-8 String Pair】
     //3.1.3.3 Will Topic 【UTF-8 String】
     //3.1.3.4 Will Payload【 Binary Data】
     //3.1.3.5 User Name【UTF-8 String】
     //3.1.3.6 Password【 Binary Data】
  //3.1.4 CONNECT Actions


   public static getFixHeader(): Uint8Array{
      let remainLength: number = 0

      //3.1.1 CONNECT Fixed Header - 包類型
       let abPacketType = new ArrayBuffer(1)
       const dv_abPacketType = new DataView(abPacketType);
       dv_abPacketType.setInt8(0, 0x10)

      //3.1.2.1 Protocol Name

      let u8a_protolName = this.utf8String('MQTT')
      remainLength += u8a_protolName.length

      //3.1.2.2 Protocol Version
      let version = new Uint8Array([5])
      remainLength++

      //3.1.2.3 Connect Flags
      const  UserNameFlag: number = 0x80
      const  PasswordFlag: number = 0x40
      const  WillRetain: number = 0x20
      const  WillQoS0: number = 0x00
      const  WillQoS1: number = 0x8
      const  WillQoS2: number = 0x10
      const  WillQoS3: number = 0x18
      const  WillFlag: number = 0x4
      const  CleanStart: number = 0x2

      let connectFlags: number = 0
      //可以根據(jù)實際對外暴露的接口，在這里進行與運算
      connectFlags = CleanStart
      let u8a_connectFlags = new Uint8Array([connectFlags])
      remainLength++

      //3.1.2.10 Keep Alive
      const keepAlive = 60

      let u8a_keepalive = new Uint8Array([(keepAlive & 0xff00) > > 8 , keepAlive & 0xff])
      remainLength += 2

      //3.1.2.11 CONNECT Properties
      //3.1.2.11.1 Property Length
      let u8a_propertylength = new Uint8Array([0])
      remainLength++

      //3.1.3 CONNECT Payload
      //3.1.3.1 Client Identifier (ClientID)
      let u8a_clientidentifier = this.utf8String('Harvey鴻蒙')
      remainLength += u8a_clientidentifier.length

      //3.1.1 CONNECT Fixed Header - 包剩余長度
      let abRemainLength = new ArrayBuffer(1)
      const dv_remainLength = new DataView(abRemainLength);
      dv_remainLength.setInt8(0, remainLength)

      let allIndex: number = 0
      let allUint8Array = new Uint8Array(2 + remainLength)
      allUint8Array[allIndex++] = dv_abPacketType.getUint8(0) //包類型
      allUint8Array[allIndex++] = dv_remainLength.getUint8(0) //包剩余長度
      u8a_protolName.forEach((value)= >{                       //協(xié)議名稱
         allUint8Array[allIndex++] = value
      })
      version.forEach((value)= >{                              //協(xié)議版本號
         allUint8Array[allIndex++] = value
      })
      u8a_connectFlags.forEach((value)= >{                     //連接標志
         allUint8Array[allIndex++] = value
      })
      u8a_keepalive.forEach((value)= >{                        //長連?；顣r間
         allUint8Array[allIndex++] = value
      })
      u8a_propertylength.forEach((value)= >{                   //連接屬性長度
         allUint8Array[allIndex++] = value
      })
      u8a_clientidentifier.forEach((value)= >{                 //客戶端名稱
         allUint8Array[allIndex++] = value
      })

      //數(shù)值打印
      let str = [...new Uint8Array(abPacketType),...new Uint8Array(abRemainLength), ...u8a_protolName, ...version
          , ...u8a_connectFlags, ...u8a_keepalive, ...u8a_propertylength, ...u8a_clientidentifier]
         .map(x = > x.toString(16).padStart(2, '0'))
         .join(' ')

      console.log(str)

      let allStr: string = ''

      allUint8Array.forEach((value) = > {
         allStr = allStr.concat(value.toString(16).padStart(2, '0')).concat(' ')
      })
      console.log(allStr)

      return allUint8Array

   }

   private static utf8String(content: string): Uint8Array{
      const encoder = new util.TextEncoder()
      let u8a_encoder = encoder.encodeInto(content)

      let encoderLength = u8a_encoder.length

      let abEncoder = new ArrayBuffer(encoderLength + 2)
      const dv_encoder = new DataView(abEncoder)
      dv_encoder.setInt8(0, (encoderLength & 0xff00) > > 8)
      dv_encoder.setInt8(1, encoderLength & 0x00ff)

      let index: number = 2
      u8a_encoder.forEach( (value) = > {
         dv_encoder.setInt8(index++, value)
      })

      return new Uint8Array(abEncoder)
   }

}
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解析MQTT請求連接ACK數(shù)據(jù)

DevEco IDE 日志控制臺

tcpSocket.on('message' , ( value: {message: ArrayBuffer, remoteInfo: socket.SocketRemoteInfo} ) = > {

  let str = [...new Uint8Array(value.message)]
    .map(x = > x.toString(16).padStart(2, '0'))
    .join(' ')

  console.log(str)

  let index: number = 0

  let uint8Array = new Uint8Array(value.message)

  let cfh = uint8Array[index]

  index++

  //3.2.1 CONNACK Fixed Header
  //解析MQTT ACK數(shù)據(jù)，轉(zhuǎn)換為日志輸出
  if(cfh == 32){
    console.log('Fixed Header format：CONNACK('+cfh+')')
    MQTTConnectACK.parse(index, uint8Array)
  }

  getContext().eventHub.emit('remotemsg', str)
})
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import MQTTTool from './MQTTTool'

export default class MQTTConnectACK{

  public static parse(index: number, uint8Array: Uint8Array) {
      let remainLength = uint8Array[index]
      console.log('Remaining Length：' + remainLength.toString(16))
      index++

      if(remainLength == 0){
        return
      }

      let remainIndex: number = 0

      //3.2.2 CONNACK Variable Header
      //3.2.2.1 Connect Acknowledge Flags
      let caf = uint8Array[index]
      console.log('Connect Acknowledge Flags：' + caf.toString(16))
      index++
      remainIndex++

      if(remainIndex >= remainLength){
        return
      }

      //3.2.2.2 Connect Reason Code
      let crc = uint8Array[index]
      let des: string = ''
      if(crc == 0){
         des = 'Success'
      } else if(crc == 128){
         des = 'Unspecified error'
      } else if(crc == 129){
         des = 'Malformed Packet'
      } else if(crc == 130){
        des = 'Protocol Error'
      } else if(crc == 131){
        des = 'Implementation specific error'
      } else if(crc == 132){
        des = 'Unsupported Protocol Version'
      } else if(crc == 133){
        des = 'Client Identifier not valid'
      } else if(crc == 134){
        des = 'Bad User Name or Password'
      } else if(crc == 135){
        des = 'Not authorized'
      } else if(crc == 136){
        des = 'Server unavailable'
      } else if(crc == 137){
        des = 'Server busy'
      } else if(crc == 138){
        des = 'Banned'
      } else if(crc == 140){
        des = 'Bad authentication method'
      } else if(crc == 144){
        des = 'Topic Name invalid'
      } else if(crc == 149){
        des = 'Packet too large'
      } else if(crc == 151){
        des = 'Quota exceeded'
      } else if(crc == 153){
        des = 'Payload format invalid'
      } else if(crc == 154){
        des = 'Retain not supported'
      } else if(crc == 155){
        des = 'QoS not supported'
      } else if(crc == 156){
        des = 'Use another server'
      } else if(crc == 157){
        des = 'Server moved'
      } else if(crc == 158){
        des = 'Connection rate exceeded'
      }
      console.log('Connect Reason Code：' + des)

      index++
      remainIndex++

      if(remainIndex >= remainLength){
        return
      }

      //3.2.2.3 CONNACK Properties
      //3.2.2.3.1 Property Length
      let propertyLength = uint8Array[index]
      console.log('Property Length：' + propertyLength.toString(16))

      index++
      remainIndex++

      if(propertyLength != 0){

        while (true){
          //判斷類型
          let nextType = uint8Array[index]

          index++
          remainIndex++
          if(remainIndex >= remainLength){
            return
          }

          if(nextType == 17){ //值為4個字節(jié)
            //3.2.2.3.2 Session Expiry Interval
            let costByteNumber = MQTTTool.parseFourByte(uint8Array, index, "Session Expiry Interval：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 33){//值為2個字節(jié)

            //3.2.2.3.3 Receive Maximum
            let costByteNumber = MQTTTool.parseTwoByte(uint8Array, index, "Receive Maximum：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 36){ //值為1個字節(jié)

            //3.2.2.3.4 Maximum QoS
            let mq = uint8Array[index]
            console.log('Maximum QoS：' + mq.toString(16))

            index++
            remainIndex++

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 37) {  //值為1個字節(jié)
            //3.2.2.3.5 Retain Available
            let ra = uint8Array[index]
            console.log('Retain Available：' + ra.toString(16))

            index++
            remainIndex++

            if(remainIndex >= remainLength){
              return
            }
          } else if(nextType == 39) { //值為4個字節(jié)

            //3.2.2.3.6 Maximum Packet Size
            let costByteNumber = MQTTTool.parseFourByte(uint8Array, index, "Maximum Packet Size：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 18) { //UTF-8 String = 2個字節(jié) + 2個字節(jié)值的字節(jié)

            //3.2.2.3.7 Assigned Client Identifier
            let costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Assigned Client Identifier：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 34) { // 值為2個字節(jié)
            //3.2.2.3.8 Topic Alias Maximum
            let costByteNumber = MQTTTool.parseTwoByte(uint8Array, index, "Topic Alias Maximum：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 31) { //UTF-8 String = 2個字節(jié) + 2個字節(jié)值的字節(jié)
            //3.2.2.3.9 Reason String
            let costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Reason String：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 38) {//UTF-8 String Pair = （2個字節(jié) + 2個字節(jié)值的字節(jié)）+（2個字節(jié) + 2個字節(jié)值的字節(jié)）
            //3.2.2.3.10 User Property
            let costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "User Property：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 40) { //值為1個字節(jié)
            //3.2.2.3.11 Wildcard Subscription Available
            let wsa = uint8Array[index]
            console.log('Wildcard Subscription Available：' + wsa.toString(16))

            index++
            remainIndex++

            if(remainIndex >= remainLength){
              return
            }
          } else if(nextType == 41) { //值為1個字節(jié)
            //3.2.2.3.12 Subscription Identifiers Available
            let sia = uint8Array[index]
            console.log('Subscription Identifiers Available：' + sia.toString(16))

            index++
            remainIndex++

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 42) { //值為1個字節(jié)
            //3.2.2.3.13 Shared Subscription Available
            let ssa = uint8Array[index]
            console.log('Shared Subscription Available：' + ssa.toString(16))

            index++
            remainIndex++

            if(remainIndex >= remainLength){
              return
            }
          } else if(nextType == 19) { //值為2個字節(jié)
            //3.2.2.3.14 Server Keep Alive
            let costByteNumber = MQTTTool.parseTwoByte(uint8Array, index, "Server Keep Alive：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 26) { //UTF-8 String = 2個字節(jié) + 2個字節(jié)值的字節(jié)
            //3.2.2.3.15 Response Information
            let costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Response Information：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 28) { //UTF-8 String = 2個字節(jié) + 2個字節(jié)值的字節(jié)
            //3.2.2.3.16 Server Reference
            let costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Server Reference：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 21) { //UTF-8 String = 2個字節(jié) + 2個字節(jié)值的字節(jié)
            //3.2.2.3.17 Authentication Method
            let costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Authentication Method：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          } else if(nextType == 22) { //Binary Data = 2個字節(jié) + 2個字節(jié)值的字節(jié)
            //3.2.2.3.18 Authentication Data
            let costByteNumber = MQTTTool.parseBinaryData(uint8Array, index, "Authentication Data：")
            index += costByteNumber
            remainIndex += costByteNumber

            if(remainIndex >= remainLength){
              return
            }

          }
        }

    }
  }

}
復(fù)制

最終效果