Spring boot 实现 WebSocket服务端

Spring boot 实现 WebSocket服务端

声明

此文档适合初次搭建websocket的情况，包含以下内容

• websocket启动需要的配置
• ws地址
• 注入业务service
• 上传内容过大问题，如：base64的图片

websocket服务端

websocket客户端

准备工作

引入Maven依赖

        
        <dependency>
             <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>1.2.12version>
        dependency>

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-websocketartifactId>
        dependency>

        
        <dependency>
            <groupId>org.java-websocketgroupId>
            <artifactId>Java-WebSocketartifactId>
            <version>1.3.8version>
        dependency>

添加application.yml配置文件

server:
  port: 8800
  servlet:
    context-path: /myserver
spring:
  application:
    name: websocketTest

websocket的项目配置添加完成

1. 配置

创建配置类 WebSocketConfiguration.class 实现了 ServletContextInitializer 接口

类上添加注解 @Configuration, 表明这是个配置类

package com.cloud.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
import org.springframework.web.util.WebAppRootListener;

import javax.servlet.ServletContext;

/**
 * 

 * websocket支持
 * 
 *
 * @author Administrator
 * @date 2021-04-20
 */
@Configuration
public class WebSocketConfiguration implements ServletContextInitializer {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        ServerEndpointExporter serverEndpointExporter = new ServerEndpointExporter();
        return serverEndpointExporter;
    }

    /**
     * 启动加载
     *
     * @param servletContext
     */
    @Override
    public void onStartup(ServletContext servletContext) {
        servletContext.addListener(WebAppRootListener.class);

        // 接收base64的字符串,等于50M
        servletContext.setInitParameter("org.apache.tomcat.websocket.textBufferSize", "52428800");
        servletContext.setInitParameter("org.apache.tomcat.websocket.binaryBufferSize", "52428800");
    }

    /**
     * 注入业务service
     *
     * @param sxBlxxjlbService
     */
    @Autowired
    public void setWebSocketServer(MyService myService) {
        WebSocketServer.myService = myService;
    } 
}   

2. WebSocket服务类

创建websocket服务实现类

package com.websocket.websocket;

import com.websocket.service.MyService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.websocket.EncodeException;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * 

 * websocket服务实现
 * 
 *
 * @author Administrator
 * @date 2021-04-20
 */
@Component
@ServerEndpoint(value = "/websocketServer/{userId}")
public class WebSocketServer {

    private static final Logger LOGGER = LoggerFactory.getLogger(WebSocketServer.class);
    /**
     * 业务service
     */
    public static MyService myService;

    /**
     * concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。
     */
    private static ConcurrentMap<String, WebSocketServer> webSocketMap = new ConcurrentHashMap<>();
    /**
     * 与某个客户端的连接会话，需要通过它来给客户端发送数据
     */
    private Session session;
    /**
     * 接收userId
     */
    private String userId;

    @OnOpen
    public void onOpen(Session session, @PathParam("userId") String userId) {
        this.session = session;
        this.userId = userId;

        if (webSocketMap.containsKey(userId)) {
            // 重新连接,踢掉上次的连接信息
            WebSocketServer webSocketServer = webSocketMap.get(userId);
            webSocketServer.onClose();
        }
        webSocketMap.put(userId, this);
        LOGGER.info("用户登录:" + userId);
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        if (webSocketMap.containsKey(userId)) {
            try {
                // 踢掉已经连接的人
                this.session.close();
                webSocketMap.remove(userId);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        LOGGER.info("用户退出:" + userId);
    }

    /**
     * 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) {
        LOGGER.debug("用户消息:" + userId + ",报文:" + message);
        // 根据当前的userId类型判断转发到pc端还是app
        try {
            sendInfo(this.userId, "你好，我是" + myService.getMyIdentity());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * @param error 错误
     */
    @OnError
    public void onError(Throwable error) {
        try {
            String errorMsg = "用户错误:" + userId + ",原因:" + error.getMessage();
            sendMessage(errorMsg);
            LOGGER.error(errorMsg);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 实现服务器主动推送-string
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }

    /**
     * 实现服务器主动推送-object
     */
    public void sendMessage(Object message) throws EncodeException, IOException {
        this.session.getBasicRemote().sendObject(message);
    }

    /**
     * 发送自定义消息
     */
    public static String sendInfo(String userId, String message) throws IOException {
        if (webSocketMap.containsKey(userId)) {
            webSocketMap.get(userId).sendMessage(message);
            return "发送成功";
        }
        String errorMsg = "用户" + userId + ",不在线！";
        LOGGER.info(errorMsg);
        return errorMsg;
    }

    /**
     * 发送自定义消息
     */
    public static void sendInfo(String userId, Object message) throws IOException, EncodeException {
        if (webSocketMap.containsKey(userId)) {
            webSocketMap.get(userId).sendMessage(message);
            return;
        }
        LOGGER.info("用户" + userId + ",不在线！");
    }

}

至此WebSocket的代码已经写完！

• websocket的地址 ws://+IP地址+项目端口号+servlet.context-path+websocket名称

如：ws://127.0.0.1:8800/myserver/websocketServer/123456789

其中websocketServer是WebSocketServer 类上的注解@ServerEndpoint(value = “/websocketServer/{userId}”)

servlet.context-path 如果没有配置就不用添加

• 注入业务service实现

首先在websocket配置类中，使用依赖注入

/**
    * 注入业务service
    *
    * @param sxBlxxjlbService
    */
   @Autowired
   public void setWebSocketServer(MyService myService) {
       WebSocketServer.myService = myService;
   } 

然后在websocket服务实现类中，添加静态的业务service实现

	/**
    * 业务service
    */
   public static MyService myService;

这样就实现了在websocket服务中注入业务service，否则会报错。

3. 编写客户端，测试websocket服务

websocket测试代码

采用WebSocketClient作为客户端测试

package com.websocket.websocket;

import org.java_websocket.WebSocket;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;

import java.net.URI;
import java.net.URISyntaxException;

/**
 * 

 * 我的测试
 * 
 *
 * @author Administrator
 */
public class TestMain {

    /**
     * 我的测试
     *
     * @param args
     */
    public static void main(String[] args) {
        try {
            String url = "ws://127.0.0.1:8800/myserver/websocketServer/123456789";
            WebSocketClientTest webSocketTest = new WebSocketClientTest(new URI(url));
            webSocketTest.connect();
            while (!webSocketTest.getReadyState().equals(WebSocket.READYSTATE.OPEN)) {
                System.out.println("请稍后,连接中...");
                Thread.sleep(1000);
            }
            webSocketTest.send("你好，服务器，我是客户端");
        } catch (URISyntaxException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    static class WebSocketClientTest extends WebSocketClient {

        /**
         * Constructs a WebSocketClient instance and sets it to the connect to the
         * specified URI. The channel does not attampt to connect automatically. The connection
         * will be established once you call connect.
         *
         * @param serverUri the server URI to connect to
         */
        public WebSocketClientTest(URI serverUri) {
            super(serverUri);
        }

        /**
         * Called after an opening handshake has been performed and the given websocket is ready to be written on.
         *
         * @param handshakedata The handshake of the websocket instance
         */
        @Override
        public void onOpen(ServerHandshake handshakedata) {

        }

        /**
         * Callback for string messages received from the remote host
         *
         * @param message The UTF-8 decoded message that was received.
         * @see #onMessage(ByteBuffer)
         **/
        @Override
        public void onMessage(String message) {
            System.out.println(message);
        }

        /**
         * Called after the websocket connection has been closed.
         *
         * @param code   The codes can be looked up here: {@link CloseFrame}
         * @param reason Additional information string
         * @param remote
         **/
        @Override
        public void onClose(int code, String reason, boolean remote) {

        }

        /**
         * Called when errors occurs. If an error causes the websocket connection to fail {@link #onClose(int, String, boolean)} will be called additionally.

         * This method will be called primarily because of IO or protocol errors.

         * If the given exception is an RuntimeException that probably means that you encountered a bug.

         *
         * @param ex The exception causing this error
         **/
        @Override
        public void onError(Exception ex) {

        }
    }
}

总结

1. 使用spring的websocket需要服务配置
2. 对于业务service实现需要在配置类中引入，不能直接在WebSocket服务中注入，会报错