Spring Boot - Web Socket

Dans ce chapitre, voyons comment créer une application Web interactive à l'aide de Spring Boot avec des sockets Web.

Pour créer une application Web interactive dans Spring Boot avec Web socket, vous devez ajouter les dépendances suivantes.

Les utilisateurs Maven doivent ajouter les dépendances suivantes dans le fichier pom.xml.

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
<dependency>
   <groupId>org.webjars</groupId>
   <artifactId>webjars-locator</artifactId>
</dependency>
<dependency>
   <groupId>org.webjars</groupId>
   <artifactId>sockjs-client</artifactId>
   <version>1.0.2</version>
</dependency>

<dependency>
   <groupId>org.webjars</groupId>
   <artifactId>stomp-websocket</artifactId>
   <version>2.3.3</version>
</dependency>
<dependency>
   <groupId>org.webjars</groupId>
   <artifactId>bootstrap</artifactId>
   <version>3.3.7</version>        </dependency>
<dependency>
   <groupId>org.webjars</groupId>
   <artifactId>jquery</artifactId>
   <version>3.1.0</version>
</dependency>

Les utilisateurs Gradle peuvent ajouter les dépendances suivantes dans votre fichier build.gradle -

compile("org.springframework.boot:spring-boot-starter-websocket")
compile("org.webjars:webjars-locator")
compile("org.webjars:sockjs-client:1.0.2")
compile("org.webjars:stomp-websocket:2.3.3")
compile("org.webjars:bootstrap:3.3.7")
compile("org.webjars:jquery:3.1.0")

Créons un contrôleur de gestion des messages pour travailler avec la messagerie STOMP. Les messages STOMP peuvent être acheminés vers le fichier de classe @Controller. Par exemple, GreetingController est mappé pour gérer les messages vers la destination «/ hello».

package com.tutorialspoint.websocketapp;

import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.messaging.handler.annotation.SendTo;
import org.springframework.stereotype.Controller;

@Controller
public class GreetingController {
   @MessageMapping("/hello")
   @SendTo("/topic/greetings")
   public Greeting greeting(HelloMessage message) throws Exception {
      Thread.sleep(1000); // simulated delay
      return new Greeting("Hello, " + message.getName() + "!");
   }
}

Maintenant, configurez Spring pour la messagerie STOMP. Écrivez un fichier de classe WebSocketConfig qui étend la classe AbstractWebSocketMessageBrokerConfigurer comme indiqué ci-dessous.

package com.tutorialspoint.websocketapp;

import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.simp.config.MessageBrokerRegistry;
import org.springframework.web.socket.config.annotation.AbstractWebSocketMessageBrokerConfigurer;
import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
import org.springframework.web.socket.config.annotation.StompEndpointRegistry;

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
   @Override
   public void configureMessageBroker(MessageBrokerRegistry config) {
      config.enableSimpleBroker("/topic");
      config.setApplicationDestinationPrefixes("/app");
   }
   @Override
   public void registerStompEndpoints(StompEndpointRegistry registry) {
      registry.addEndpoint("/tutorialspoint-websocket").withSockJS();
   }
}

L'annotation @EnableWebSocketMessageBroker est utilisée pour configurer le courtier de messages Web socket pour créer des points de terminaison STOMP.

Vous pouvez créer un fichier client de navigateur sous le src / main / resources / static / index.html comme indiqué -

<!DOCTYPE html>
<html>
   <head>
      <title>Hello WebSocket</title>
      <link href = "/webjars/bootstrap/css/bootstrap.min.css" rel = "stylesheet">
      <link href = "/main.css" rel = "stylesheet">
      <script src = "/webjars/jquery/jquery.min.js"></script>
      <script src = "/webjars/sockjs-client/sockjs.min.js"></script>
      <script src = "/webjars/stomp-websocket/stomp.min.js"></script>
      <script src = "/app.js"></script>
   </head>
   
   <body>
      <noscript>
         <h2 style = "color: #ff0000">
            Seems your browser doesn't support Javascript! Websocket relies on Javascript being
            enabled. Please enable Javascript and reload this page!
         </h2>
      </noscript>
      <div id = "main-content" class = "container">
         <div class = "row">
            <div class = "col-md-6">
               <form class = "form-inline">
                  <div class = "form-group">
                     <label for = "connect">WebSocket connection:</label>
                     <button id = "connect" class = "btn btn-default" type = "submit">Connect</button>
                     <button id = "disconnect" class = "btn btn-default" type = "submit" disabled = "disabled">Disconnect
                     </button>
                  </div>
               </form>
            </div>
            
            <div class = "col-md-6">
               <form class = "form-inline">
                  <div class = "form-group">
                     <label for = "name">What is your name?</label>
                     <input type = "text" id = "name" class = "form-control" placeholder = "Your name here...">
                  </div>
                  <button id = "send" class = "btn btn-default" type = "submit">Send</button>
               </form>
            </div>
         </div>
         
         <div class  =  "row">
            <div class  =  "col-md-12">
               <table id  =  "conversation" class = "table table-striped">
                  <thead>
                     <tr>
                        <th>Greetings</th>
                     </tr>
                  </thead>
                  <tbody id  =  "greetings"></tbody>
               </table>
            </div>
         </div>
      </div>
   </body>
</html>

Créons un fichier app.js pour consommer et produire les messages en utilisant STOMP.

var stompClient = null;

function setConnected(connected) {
   $("#connect").prop("disabled", connected);
   $("#disconnect").prop("disabled", !connected);
   
   if (connected) {
      $("#conversation").show();
   } else {
      $("#conversation").hide();
   }
   $("#greetings").html("");
}

function connect() {
   var socket = new SockJS('/tutorialspoint-websocket');
   stompClient = Stomp.over(socket);
   stompClient.connect({}, function (frame) {
      setConnected(true);
      console.log('Connected: ' + frame);
      stompClient.subscribe('/topic/greetings', function (greeting) {
         showGreeting(JSON.parse(greeting.body).content);
      });
   });
}
function disconnect() {
   if (stompClient !== null) {
      stompClient.disconnect();
   }
   setConnected(false);
   console.log("Disconnected");
}
function sendName() {
   stompClient.send("/app/hello", {}, JSON.stringify({'name': $("#name").val()}));
}
function showGreeting(message) {
   $("#greetings").append("<tr><td>" + message + "</td></tr>");
}
$(function () {
   $( "form" ).on('submit', function (e) {e.preventDefault();});
   $( "#connect" ).click(function() { connect(); });
   $( "#disconnect" ).click(function() { disconnect(); });
   $( "#send" ).click(function() { sendName(); });
});

Le code de l'application principale Spring Boot est indiqué ci-dessous.

package com.tutorialspoint.websocketapp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class WebsocketappApplication {
   public static void main(String[] args) {
      SpringApplication.run(WebsocketappApplication.class, args);
   }  
}

Le fichier de configuration de construction complet est donné ci-dessous.

Maven – pom.xml

<?xml version = "1.0" encoding = "UTF-8"?>
<project xmlns = "http://maven.apache.org/POM/4.0.0" 
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation = "http://maven.apache.org/POM/4.0.0 
   http://maven.apache.org/xsd/maven-4.0.0.xsd">
   
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.tutorialspoint</groupId>
   <artifactId>websocketapp</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>websocketapp</name>
   <description>Demo project for Spring Boot</description>

   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>1.5.9.RELEASE</version>
   </parent>

   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-websocket</artifactId>
      </dependency>
      <dependency>
         <groupId>org.webjars</groupId>
         <artifactId>webjars-locator</artifactId>
      </dependency>
      <dependency>
         <groupId>org.webjars</groupId>
         <artifactId>sockjs-client</artifactId>
         <version>1.0.2</version>
      </dependency>
      
      <dependency>
         <groupId>org.webjars</groupId>
         <artifactId>stomp-websocket</artifactId>
         <version>2.3.3</version>
      </dependency>
      <dependency>
         <groupId>org.webjars</groupId>
         <artifactId>bootstrap</artifactId>
         <version>3.3.7</version>
      </dependency>
      
      <dependency>
         <groupId>org.webjars</groupId>
         <artifactId>jquery</artifactId>
         <version>3.1.0</version>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>
   
   <properties>
      <java.version>1.8</java.version>
   </properties>
   
   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>
   
</project>

Gradle – build.gradle

buildscript {
   repositories {
      mavenCentral()
   }
   dependencies {
      classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.9.RELEASE")
   }
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'

jar {
   baseName = 'websocketapp'
   version =  '0.1.0'
}
sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
   mavenCentral()
}
dependencies {
   compile("org.springframework.boot:spring-boot-starter-websocket")
   compile("org.webjars:webjars-locator")
   compile("org.webjars:sockjs-client:1.0.2")
   compile("org.webjars:stomp-websocket:2.3.3")
   compile("org.webjars:bootstrap:3.3.7")
   compile("org.webjars:jquery:3.1.0")

   testCompile("org.springframework.boot:spring-boot-starter-test")
}