[网络协议]SSM---XML配置文件方式配置WebSocket

1、pom.xml导入websocket依赖

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-messaging</artifactId>
    <version>4.0.5.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-websocket</artifactId>
    <version>4.0.5.RELEASE</version>
</dependency>

2、websocket握手拦截器

import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.HandshakeInterceptor;

import java.util.Map;

/**
 * websocket握手拦截器，拦截握手前，握手后的两个事件
 */
@Component
public class HandShakeInterceptor implements HandshakeInterceptor {

    @Override
    public boolean beforeHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Map<String, Object> map) throws Exception {
        if (serverHttpRequest instanceof ServletServerHttpRequest) {
            // 获取到请求
            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) serverHttpRequest;
            String userName = "websocket_test";
            map.put("WEBSOCKET_USERNAME", userName);
        }
        return true;
    }

    @Override
    public void afterHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Exception e) {

    }
}

3、websocket实现

import com.util.ResultUtils;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.*;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

@Component
public class WebSocketHander implements WebSocketHandler {
    private static final List<WebSocketSession> USERS = new ArrayList<>();

    @Override
    public void afterConnectionEstablished(WebSocketSession webSocketSession) throws Exception {
        System.out.println("---------------------------websocket连接成功-------------------------");
        USERS.add(webSocketSession);
        //每次有新的连接，就加入到user集合中
        String username = (String) webSocketSession.getAttributes().get("WEBSOCKET_USERNAME");
        if (username != null) {
            //确保每个用户信息都能同步到
            for (WebSocketSession wss : USERS) {
                // 发送信息告诉所有的websocket客户端，连接成功了
                wss.sendMessage(new TextMessage(ResultUtils.successWithMessage("websocket连接成功！")));
            }
        }
    }

    // websocket接收前端请求的数据，这里我们不需要前端请求，所以不写
    @Override
    public void handleMessage(WebSocketSession webSocketSession, WebSocketMessage<?> webSocketMessage) throws Exception {
        // websocket发送数据
//        sendMessageToUsers(new TextMessage(ResultUtils.successWithDataAndMessage(webSocketMessage.getPayload(), "websocket数据！")));
    }


    @Override
    public void handleTransportError(WebSocketSession webSocketSession, Throwable throwable) throws Exception {
        // 连接错误，移除对应的客户端
        USERS.remove(webSocketSession);
    }

    @Override
    public void afterConnectionClosed(WebSocketSession webSocketSession, CloseStatus closeStatus) throws Exception {
        // 关闭连接。移除对应的客户端
        USERS.remove(webSocketSession);
    }

    @Override
    public boolean supportsPartialMessages() {
        return false;
    }

    /**
     * 给所有在线用户发送消息
     *
     * @param obj  发送的数据
     * @param code 表示成功还是失败
     */
    public void sendMessageToUsers(Object obj, String code) {
        TextMessage message;
        if (code.equals("success")) {
            message = new TextMessage(ResultUtils.successWithDataAndMessage(obj, "websocket发送数据！"));
        } else {
            message = new TextMessage(ResultUtils.errorWithMessage((String) obj));
        }

        for (WebSocketSession user : USERS) {
            try {
                if (user.isOpen()) {
                    user.sendMessage(message);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 给某个用户发送消息
     *
     * @param userName websocket名称
     * @param obj      发送的数据
     */
    public void sendMessageToUser(String userName, Object obj) {
        TextMessage message = new TextMessage(ResultUtils.successWithDataAndMessage(obj, "websocket发送数据！"));
        for (WebSocketSession user : USERS) {
            if (user.getAttributes().get("WEBSOCKET_USERNAME").equals(userName)) {
                try {
                    if (user.isOpen()) {
                        user.sendMessage(message);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                break;
            }
        }
    }
}

4、XML文件配置请求路径

<!--配置 webSocket-->
<bean id="customHandler" class="com.controller.websocket.WebSocketHander"/>
<websocket:handlers>
    <!--指定 webSocket 请求地址-->
    <websocket:mapping path="/websocket.do" handler="customHandler"/>
    <!--webSocket 握手拦截器-->
    <websocket:handshake-interceptors>
        <bean class="com.controller.websocket.HandShakeInterceptor"/>
    </websocket:handshake-interceptors>
</websocket:handlers>

5、websocket请求路径

ws://localhost/websocket.do