WebSocket（一）Server 简单搭建

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WebSocket（一）Server 简单搭建，基于 Spring Boot

Maven 依赖

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<dependencies>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
  </dependency>

  <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.47</version>
  </dependency>
  <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.12.0</version>
  </dependency>
  <dependency>
    <groupId>org.java-websocket</groupId>
    <artifactId>Java-WebSocket</artifactId>
    <version>1.5.3</version>
  </dependency>
  <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-collections4</artifactId>
    <version>4.4</version>
  </dependency>
</dependencies>

核心配置

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import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Configuration
public class WebSocketConfig {
  
  /**
  * 注入一个ServerEndpointExporter,该Bean会自动注册使用@ServerEndpoint注解申明的websocket endpoint
  */
  @Bean
  public ServerEndpointExporter serverEndpointExporter() {
    return new ServerEndpointExporter();
  }
}

Demo

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import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.util.concurrent.atomic.AtomicInteger;

@Slf4j
@Component
@ServerEndpoint(value = "/demo")
public class WebSocketDemo {
  
  /**
  * 记录当前在线连接数
  */
  private static final AtomicInteger onlineCount = new AtomicInteger(0);
  
  /**
  * 连接建立成功调用的方法
  */
  @OnOpen
  public void onOpen(Session session) {
    onlineCount.incrementAndGet();
    log.info("有新连接加入：{}，当前在线人数为：{}", session.getId(), onlineCount.get());
  }
  
  /**
  * 连接关闭调用的方法
  */
  @OnClose
  public void onClose(Session session) {
    onlineCount.decrementAndGet();
    log.info("有一连接关闭：{}，当前在线人数为：{}", session.getId(), onlineCount.get());
  }
  
  /**
  * 收到客户端消息后调用的方法
  *
  * @param message 客户端发送过来的消息
  */
  @OnMessage
  public void onMessage(String message, Session session) {
    log.info("服务端收到客户端[{}]的消息:{}", session.getId(), message);
    this.sendMessage("Hello, " + message, session);
  }
  
  @OnError
  public void onError(Session session, Throwable error) {
    log.error("发生错误");
    error.printStackTrace();
  }
  
  /**
  * 服务端发送消息给客户端
  */
  private void sendMessage(String message, Session toSession) {
    try {
      log.info("服务端给客户端[{}]发送消息{}", toSession.getId(), message);
      toSession.getBasicRemote().sendText(message);
    } catch (Exception e) {
      log.error("服务端发送消息给客户端失败：{}", e.getMessage());
    }
  }
}

配置文件

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server:
  port: 9716

准备测试

文件路径：src\main\resources\static\index.html

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<!DOCTYPE HTML>
<html>
<head>
    <title>My WebSocket</title>
</head>
<body>
<input id="text" type="text" />
<button onclick="send()">Send</button>
<button onclick="closeWebSocket()">Close</button>
<div id="message"></div>
</body>

<script type="text/javascript">
    var websocket = null;

    //判断当前浏览器是否支持WebSocket, 主要此处要更换为自己的地址
    if ('WebSocket' in window) {
        websocket = new WebSocket("ws://localhost:9716/demo");
    } else {
        alert('Not support websocket')
    }

    //连接发生错误的回调方法
    websocket.onerror = function() {
        setMessageInnerHTML("error");
    };

    //连接成功建立的回调方法
    websocket.onopen = function(event) {
        //setMessageInnerHTML("open");
    }

    //接收到消息的回调方法
    websocket.onmessage = function(event) {
        setMessageInnerHTML(event.data);
    }

    //连接关闭的回调方法
    websocket.onclose = function() {
        setMessageInnerHTML("close");
    }

    //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
    window.onbeforeunload = function() {
        websocket.close();
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML) {
        document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }

    //关闭连接
    function closeWebSocket() {
        websocket.close();
    }

    //发送消息
    function send() {
        var message = document.getElementById('text').value;
        websocket.send(message);
    }
</script>
</html>

测试

http://localhost:9716/
image.png

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