Websocket 应用组成

1、pom.xml

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

2、Bean

@Configuration
public class WebsocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {  // 打jar包需要，打war包则不要
        return new ServerEndpointExporter();
    }
}

3、Endpoint

@Component
@ServerEndpoint(value = "/socket/log/{logId}")
public class LogWebSocket {
    // 记录当前连接数
    public static AtomicInteger onlineCount = new AtomicInteger(0);
    // 存放所有连接
    public static Map<String, Session> clients = new ConcurrentHashMap<>();

    @OnOpen
    public void onOpen(Session session) {
        onlineCount.incrementAndGet(); // 连接数加1
        clients.put(session.getId(), session);
        String logId = session.getPathParameters().get("logId");  // 可以从Endpoint Url 中获取参数
    }

    @OnClose
    public void onClose(Session session) {
        onlineCount.decrementAndGet(); // 连接数减1
        clients.remove(session.getId());
    }

    @OnError
    public void onError(Session session, Throwable error) {
        error.printStackTrace();
    }

    // 接收来自客户端的消息
    @OnMessage
    public void onMessage(String message, Session session) {
        LogMessage logMessage = JSON.parseObject(message, LogMessage.class);  // 把前端传来的JSON字符串转换成对象
        this.sendMessage(session,"Hello");
    }

    private void sendMessage(Session session, String message) {
        try {
            session.getBasicRemote().sendText(message);  // 发送消息给客户端
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Nginx 配置 Websocket

    location ^~ /socket {
            proxy_pass http://socket-service;
            
        proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
         
            proxy_connect_timeout 4s; 
            proxy_read_timeout 7200s; 
            proxy_send_timeout 12s; 
        }      

整合 JWT

目的：对客户端进行 认证
JwtTokenUtil 参考：//www.greatytc.com/p/57e50b2b1144
1、登录时 生成 token 返回给客户端

String jwt = jwtTokenUtil.generateToken(username);

2、客户端连接Websocket 时 URL带上 ?token=，服务端验证token

    @OnOpen
    public void onOpen(Session session) {
        Map<String, List<String>> parameterMap = session.getRequestParameterMap();
        String jwt = parameterMap.get("token").get(0);  // 从URL参数里获取 token
        String username = jwtTokenUtil.getUsernameFromToken(jwt);

        if (username != null && jwtTokenUtil.validateToken(jwt, username)) {  // 验证token
            // 连接后的业务逻辑
        }
        else{
            session.close();
        }
    }