本篇分享一下 HarmonyOS 中的Socket使用方法
将从2个方面实践：
- HarmonyOS 手机应用连接PC端 SocketServer
- HarmonyOS 手机应用连接MQTT 服务端
通过循序渐进的方式，全面了解实践HarmonyOS中的Socket用法
学习本章前先熟悉文档开发知识更新库gitee.com/li-shizhen-skin/harmony-os/blob/master/README.md前往。
注意：编译时IDE会给出如下警告提示，@ohos.net.socket 这个包没有验证过。
或者+mau123789熟悉文档是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.
官方文档说明
引入Socket包
import socket from '@ohos.net.socket';
创建TCPSocket，连接远端服务器
//注意，这里声明变量tcp, 建议将类型加上，否则不利于IDE联想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. 绑定本机地址和端口
tcp.bind(bindAddress, err => {if(err){console.log('1-' + JSON.stringify(err))return}//2. 连接远端服务器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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状态监听
订阅“连接”
tcp.on('connect', () => {});
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解除“连接”订阅
tcp.off('connect', () => {});
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订阅“消息”
tcp.on('message', () => {//即：可以在这里随时接收到服务端发送过来的消息
});
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解除“消息”订阅
tcp.off('message', () => {});
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发送消息
let msg: string = '我是HarmonyOS客户端'tcp.send({data: msg}, (error)=>{if(error) {console.log('消息没有发送成功： ' + JSON.stringify(error))} else {console.log('消息发送成功')}
})
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实践：实现Socket与ServerSocket通信
创建ServerSocket 服务
这里使用IntelliJ IDEA创建一个Java工程，然后运行在自己电脑上即可使用
如果你实在没法自己实现ServerSocket，可以在网上找一个调试Socket的工具
监听客户端接入
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. 建立客户端监听new Thread(new Runnable() {@Overridepublic void run() {while (true){try {Socket clientSocket = serverSocket.accept();System.out.println("客户端:" + clientSocket.getInetAddress().getLocalHost()+"已连接到服务器");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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监听客户端消息且自动回复
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();}}@Overridepublic 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();}//释放资源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();}}//读取客户端消息， 注意：这里是为了省事，用的readLine接口//如果消息中有换行符，则会丢失消息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("接收消息失败:" + e.getMessage());}}//自动回复客户端消息private void responseMessage(){try {BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));bw.write(System.currentTimeMillis() + "亲爱的客户端，已收到您的来信。" + lastReceiverMessage + "\n");bw.flush();System.out.println("回复消息成功");} catch (IOException e) {System.err.println("回复消息失败:" + e.getMessage());}}}
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创建客户端应用
布局
为了验证Socket，交互页面包含如下功能：
- 连接/断开
- 渲染接收到的消息
- 渲染已发送的消息
- 文字输入
- 消息发送
HarmonyOS 核心代码
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//页面创建时，注册自定义消息，监听来消息和连接状态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}})}//页面销毁时，解除所有订阅，关闭socketaboutToDisappear() {tcpSocket.off("message")tcpSocket.off("connect")tcpSocket.off("close")tcpSocket.close()tcpSocket = null}build(){Column( {space: 20} ){Row( {space: 20} ){Button('连接').width(60).height(60).fontSize(12).backgroundColor(this.connectButtonBGColor).fontColor(this.connectButtonTextColor).onClick( ()=> {if(this.isConnected){tcpSocket.close()} else {connectServer()}})}Column({space: 30}){Text('发送：' + 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: '输入文字', text: this.inputMessage}).onChange( (value) => {this.inputMessage = value}).fontSize(20).width('75%')Button('发送').fontColor(29).onClick( () => {sendMessage(this.inputMessage)this.sendMessage = this.inputMessagethis.inputMessage = ''}).width('20%')}.width('100%').justifyContent(FlexAlign.Center)}.width('100%').height('100%').alignItems(HorizontalAlign.Start).justifyContent(FlexAlign.Start).padding({top: px2vp(120)})}
}//发送消息
function sendMessage(msg: string){if(tcpSocket){tcpSocket.send({data: msg + '\n'}, (error)=>{if(error) {console.log('消息没有发送成功： ' + JSON.stringify(error))} else {getContext().eventHub.emit('')console.log('消息发送成功')}})} else {Prompt.showToast({message: '还没有连接服务器'})}
}//开始连接服务器
function connectServer(){let bindAddress = {address: '192.168.71.66',port: 1983,family: 1};let connectAddress = {address: '192.168.71.23',port: 6666 //端口号要和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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最终效果
实践：实现MQTT连接
准备MQTT Broker
MQTT使用的是 mosquitto，官网下载地址
关于MQTT的入门使用，可参见“MQTT试用”
注意：mosquitto 安装完成后，需要打开匿名设置，并且监听自己电脑的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 网址
https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.pdf
- 熟悉 “3.1 CONNECT – Connection Request”
- 熟悉 “3.2 CONNACK – Connect acknowledgement”
场景模拟
客户端使用Socket 连接mosquitto, 并且响应连接ACK
代码实现
请求连接
这部分需要分为两步：1. Socket连接 2. MQTT连接请求（即发送连接请求命令）
a. Socket连接
function connectMQTTServer(){let bindAddress = {address: '192.168.71.66',port: 1983,family: 1};let connectAddress = {address: '192.168.71.23', //MQTT服务器IPport: 1883 //MQTT服务器端口};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连接请求
tcpSocket.on('connect', () => {console.log("on connect")//拼接MQTT请求数据let connectCMD = MQTTConnect.getFixHeader()//发送MQTT连接请求命令tcpSocket.send({data: connectCMD.buffer}, (error)=>{if(error) {console.log('消息没有发送成功： ' + JSON.stringify(error))} else {console.log('消息发送成功')}})getContext().eventHub.emit('connectStatus', 'connect')
});
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构建MQTT请求连接数据
代码有点枯燥，都是要对着MQTT 5.0规范文档来实现的
import util from '@ohos.util'export default class MQTTConnect{//3.1.1 CONNECT Fixed Header 【2字节】//3.1.2 CONNECT Variable Header//3.1.2.1 Protocol Name 【6字节】//3.1.2.2 Protocol Version 【1字节】//3.1.2.3 Connect Flags 【1字节】//3.1.2.10 Keep Alive 【2字节】//3.1.2.11 CONNECT Properties//3.1.2.11.1 Property Length 【1字节】//3.1.2.11.2 Session Expiry Interval 【4字节】//3.1.2.11.3 Receive Maximum 【2字节】//3.1.2.11.4 Maximum Packet Size 【4字节】//3.1.2.11.5 Topic Alias Maximum 【2字节】//3.1.2.11.6 Request Response Information 【1字节】//3.1.2.11.7 Request Problem Information 【1字节】//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字节】//3.1.3.2.3 Payload Format Indicator 【1字节】//3.1.3.2.4 Message Expiry Interval 【4字节】//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 Actionspublic static getFixHeader(): Uint8Array{let remainLength: number = 0//3.1.1 CONNECT Fixed Header - 包类型let abPacketType = new ArrayBuffer(1)const dv_abPacketType = new DataView(abPacketType);dv_abPacketType.setInt8(0, 0x10)//3.1.2.1 Protocol Namelet u8a_protolName = this.utf8String('MQTT')remainLength += u8a_protolName.length//3.1.2.2 Protocol Versionlet version = new Uint8Array([5])remainLength++//3.1.2.3 Connect Flagsconst UserNameFlag: number = 0x80const PasswordFlag: number = 0x40const WillRetain: number = 0x20const WillQoS0: number = 0x00const WillQoS1: number = 0x8const WillQoS2: number = 0x10const WillQoS3: number = 0x18const WillFlag: number = 0x4const CleanStart: number = 0x2let connectFlags: number = 0//可以根据实际对外暴露的接口，在这里进行与运算connectFlags = CleanStartlet u8a_connectFlags = new Uint8Array([connectFlags])remainLength++//3.1.2.10 Keep Aliveconst keepAlive = 60let u8a_keepalive = new Uint8Array([(keepAlive & 0xff00) >> 8 , keepAlive & 0xff])remainLength += 2//3.1.2.11 CONNECT Properties//3.1.2.11.1 Property Lengthlet u8a_propertylength = new Uint8Array([0])remainLength++//3.1.3 CONNECT Payload//3.1.3.1 Client Identifier (ClientID)let u8a_clientidentifier = this.utf8String('Harvey鸿蒙')remainLength += u8a_clientidentifier.length//3.1.1 CONNECT Fixed Header - 包剩余长度let abRemainLength = new ArrayBuffer(1)const dv_remainLength = new DataView(abRemainLength);dv_remainLength.setInt8(0, remainLength)let allIndex: number = 0let allUint8Array = new Uint8Array(2 + remainLength)allUint8Array[allIndex++] = dv_abPacketType.getUint8(0) //包类型allUint8Array[allIndex++] = dv_remainLength.getUint8(0) //包剩余长度u8a_protolName.forEach((value)=>{ //协议名称allUint8Array[allIndex++] = value})version.forEach((value)=>{ //协议版本号allUint8Array[allIndex++] = value})u8a_connectFlags.forEach((value)=>{ //连接标志allUint8Array[allIndex++] = value})u8a_keepalive.forEach((value)=>{ //长连保活时间allUint8Array[allIndex++] = value})u8a_propertylength.forEach((value)=>{ //连接属性长度allUint8Array[allIndex++] = value})u8a_clientidentifier.forEach((value)=>{ //客户端名称allUint8Array[allIndex++] = value})//数值打印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.lengthlet 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 = 2u8a_encoder.forEach( (value) => {dv_encoder.setInt8(index++, value)})return new Uint8Array(abEncoder)}}
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解析MQTT请求连接ACK数据
DevEco IDE 日志控制台
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 = 0let uint8Array = new Uint8Array(value.message)let cfh = uint8Array[index]index++//3.2.1 CONNACK Fixed Header//解析MQTT ACK数据，转换为日志输出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 Flagslet caf = uint8Array[index]console.log('Connect Acknowledge Flags：' + caf.toString(16))index++remainIndex++if(remainIndex >= remainLength){return}//3.2.2.2 Connect Reason Codelet 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 Lengthlet propertyLength = uint8Array[index]console.log('Property Length：' + propertyLength.toString(16))index++remainIndex++if(propertyLength != 0){while (true){//判断类型let nextType = uint8Array[index]index++remainIndex++if(remainIndex >= remainLength){return}if(nextType == 17){ //值为4个字节//3.2.2.3.2 Session Expiry Intervallet costByteNumber = MQTTTool.parseFourByte(uint8Array, index, "Session Expiry Interval：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 33){//值为2个字节//3.2.2.3.3 Receive Maximumlet costByteNumber = MQTTTool.parseTwoByte(uint8Array, index, "Receive Maximum：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 36){ //值为1个字节//3.2.2.3.4 Maximum QoSlet mq = uint8Array[index]console.log('Maximum QoS：' + mq.toString(16))index++remainIndex++if(remainIndex >= remainLength){return}} else if(nextType == 37) { //值为1个字节//3.2.2.3.5 Retain Availablelet ra = uint8Array[index]console.log('Retain Available：' + ra.toString(16))index++remainIndex++if(remainIndex >= remainLength){return}} else if(nextType == 39) { //值为4个字节//3.2.2.3.6 Maximum Packet Sizelet costByteNumber = MQTTTool.parseFourByte(uint8Array, index, "Maximum Packet Size：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 18) { //UTF-8 String = 2个字节 + 2个字节值的字节//3.2.2.3.7 Assigned Client Identifierlet costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Assigned Client Identifier：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 34) { // 值为2个字节//3.2.2.3.8 Topic Alias Maximumlet costByteNumber = MQTTTool.parseTwoByte(uint8Array, index, "Topic Alias Maximum：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 31) { //UTF-8 String = 2个字节 + 2个字节值的字节//3.2.2.3.9 Reason Stringlet costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Reason String：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 38) {//UTF-8 String Pair = （2个字节 + 2个字节值的字节）+（2个字节 + 2个字节值的字节）//3.2.2.3.10 User Propertylet costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "User Property：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 40) { //值为1个字节//3.2.2.3.11 Wildcard Subscription Availablelet wsa = uint8Array[index]console.log('Wildcard Subscription Available：' + wsa.toString(16))index++remainIndex++if(remainIndex >= remainLength){return}} else if(nextType == 41) { //值为1个字节//3.2.2.3.12 Subscription Identifiers Availablelet sia = uint8Array[index]console.log('Subscription Identifiers Available：' + sia.toString(16))index++remainIndex++if(remainIndex >= remainLength){return}} else if(nextType == 42) { //值为1个字节//3.2.2.3.13 Shared Subscription Availablelet ssa = uint8Array[index]console.log('Shared Subscription Available：' + ssa.toString(16))index++remainIndex++if(remainIndex >= remainLength){return}} else if(nextType == 19) { //值为2个字节//3.2.2.3.14 Server Keep Alivelet costByteNumber = MQTTTool.parseTwoByte(uint8Array, index, "Server Keep Alive：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 26) { //UTF-8 String = 2个字节 + 2个字节值的字节//3.2.2.3.15 Response Informationlet costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Response Information：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 28) { //UTF-8 String = 2个字节 + 2个字节值的字节//3.2.2.3.16 Server Referencelet costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Server Reference：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 21) { //UTF-8 String = 2个字节 + 2个字节值的字节//3.2.2.3.17 Authentication Methodlet costByteNumber = MQTTTool.parseUTF8String(uint8Array, index, "Authentication Method：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}} else if(nextType == 22) { //Binary Data = 2个字节 + 2个字节值的字节//3.2.2.3.18 Authentication Datalet costByteNumber = MQTTTool.parseBinaryData(uint8Array, index, "Authentication Data：")index += costByteNumberremainIndex += costByteNumberif(remainIndex >= remainLength){return}}}}}}
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最终效果
![[LeetCode][LCR 179]查找总价格为目标值的两个商品](http://pic.xiahunao.cn/[LeetCode][LCR 179]查找总价格为目标值的两个商品)
)
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