springboot关于websocket依赖，pom.xml：集成springboot最小依赖，不进行任何服务连接，单独启动项目
<!-- springboot依赖maven仓库版本 -->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.5.RELEASE</version>
</parent>
<!-- SpringBoot通用依赖模块 -->
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<!-- -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<!--排除tomcat依赖: 准备替换undertow部署-->
<exclusion>
<artifactId>spring-boot-starter-tomcat</artifactId>
<groupId>org.springframework.boot</groupId>
</exclusion>
</exclusions>
</dependency>
<!--undertow容器，替换springboot内置容器tomcat-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-undertow</artifactId>
</dependency>
<!--springboot WebSocket -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
<dependencies>
1、为什么要使用WebSocket？
因为一般的请求都是HTTP请求（单向通信），HTTP是一个短连接（非持久化），且通信只能由客户端发起，HTTP协议做不到服务器主动向客户端推送消息。举个例子：前后端交互就是前端发送请求，从后端拿到数据后展示到页面，如果前端没有主动请求接口，那后端就不能发送数据给前端。然而，WebSocket确能很好的解决这个问题，服务端可以主动向客户端推送消息，客户端也可以主动向服务端发送消息，实现了服务端和客户端真正的平等。
2、配置方式一：实现ServletContextInitializer+@ServerEndpoint注解
2.1、WebSocket配置
package com.chengfu.config;
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 javax.servlet.ServletContext;
import javax.servlet.ServletException;
@Configuration
public class WebSocketConfig implements ServletContextInitializer {
// 原文链接：https://blog.csdn.net/weixin_44185837/article/details/124942482
/**
* 这个bean的注册,用于扫描带有@ServerEndpoint的注解成为websocket,如果你使用外置的tomcat就不需要该配置文件
*/
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
}
}
2.2、WebSocket连接，@ServerEndpoint
package com.chengfu.socket;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;
/**
* websocket服务端，接收websocket客户端长连接
*/
@ServerEndpoint("/websocket/api1/{id}")
@Component
@Slf4j
public class WebSocketServer {
// 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;
// session集合,存放对应的session
private static ConcurrentHashMap<Integer, Session> sessionPool = new ConcurrentHashMap<>();
// concurrent包的线程安全Set,用来存放每个客户端对应的WebSocket对象。
private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<>();
/**
* 建立WebSocket连接
*
* @param session
* @param userId 用户ID
*/
@OnOpen
public void onOpen(Session session, @PathParam(value = "id") Integer userId) {
log.info("WebSocket建立连接中,连接用户ID：{}", userId);
try {
Session historySession = sessionPool.get(userId);
// historySession不为空,说明已经有人登陆账号,应该删除登陆的WebSocket对象
if (historySession != null) {
webSocketSet.remove(historySession);
historySession.close();
}
} catch (IOException e) {
log.error("重复登录异常,错误信息：" + e.getMessage(), e);
}
// 建立连接
this.session = session;
webSocketSet.add(this);
sessionPool.put(userId, session);
log.info("建立连接完成,当前在线人数为：{}", webSocketSet.size());
}
/**
* 发生错误
*
* @param throwable e
*/
@OnError
public void onError(Throwable throwable) {
throwable.printStackTrace();
}
/**
* 连接关闭
*/
@OnClose
public void onClose() {
webSocketSet.remove(this);
log.info("连接断开,当前在线人数为：{}", webSocketSet.size());
}
/**
* 接收客户端消息
*
* @param message 接收的消息
*/
@OnMessage
public void onMessage(String message) {
log.info("收到客户端发来的消息：{}", message);
}
/**
* 推送消息到指定用户
*
* @param userId 用户ID
* @param message 发送的消息
*/
public static void sendMessageByUser(Integer userId, String message) {
log.info("用户ID：" + userId + ",推送内容：" + message);
Session session = sessionPool.get(userId);
try {
session.getBasicRemote().sendText(message);
} catch (IOException e) {
log.error("推送消息到指定用户发生错误：" + e.getMessage(), e);
}
}
/**
* 群发消息
*
* @param message 发送的消息
*/
public static void sendAllMessage(String message) {
log.info("发送消息：{}", message);
for (WebSocketServer webSocket : webSocketSet) {
try {
webSocket.session.getBasicRemote().sendText(message);
} catch (IOException e) {
log.error("群发消息发生错误：" + e.getMessage(), e);
}
}
}
}
2.3、WebSocket请求过滤
找了一些资料没发现springboot有处理@ServerEndpoint注解的websocket请求，但是可以使用servlet容器技术来实现ws请求的过滤。ws请求的拦截可以通过配置方式二来实现，详见下。
package com.chengfu.config;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.Arrays;
/**
* servlet级别请求过滤
*/
@Component
public class WebSocketFilterConfig implements Filter {
// websocket请求过滤清单
private static final String[] FILTER_LIST = {"/websocket/api1/"};
@Override
public void init(FilterConfig filterConfig) throws ServletException {
Filter.super.init(filterConfig);
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
String servletPath = httpServletRequest.getServletPath();
// anyMatch： 有一个条件满足就返回true
boolean match = Arrays.stream(FILTER_LIST).anyMatch(servletPath::startsWith);
// boolean match = Arrays.stream(FILTER_LIST).anyMatch(filterUrl -> servletPath.startsWith(filterUrl));
// 符合ws请求的url开始校验，其他请求一概放过
if (match) {
String token = httpServletRequest.getHeader("token");
if (StringUtils.isNotBlank(token)) {
filterChain.doFilter(servletRequest, servletResponse);
}
// else {
// JSONObject result = new JSONObject();
// HttpServletResponse httpServletResponse = (HttpServletResponse) servletResponse;
// httpServletResponse.setContentType("application/json;charset=utf-8");
// httpServletResponse.setCharacterEncoding("utf-8");
// PrintWriter writer = httpServletResponse.getWriter();
// writer.write(result.toJSONString());
// writer.flush();
// writer.close();
// }
} else {
// 不包含过滤清单，直接放过请求
filterChain.doFilter(servletRequest, servletResponse);
}
}
@Override
public void destroy() {
Filter.super.destroy();
}
}
2.4、postman建立客户端连接
连接成功！
3、配置方式二：实现WebSocketConfigurer+继承TextWebSocketHandler
3.1、配置：实现WebSocketConfigurer
package com.chengfu.config;
import com.chengfu.interceptor.WebSocketAuthInterceptor;
import com.chengfu.socket.WebSocketServer2;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
// 启用配置
@Configuration
// 启用websocket服务端
@EnableWebSocket
public class WebSocketConfig2 implements WebSocketConfigurer {
// 原文链接：https://blog.csdn.net/weixin_44185837/article/details/124942482
// 实现自： WebSocketConfigurer
// 注册websocket拦截器
@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry webSocketHandlerRegistry) {
webSocketHandlerRegistry
// 只有符合"/websocket/api2/**", "/websocket/api3/**"的请求url，才能进入WebSocketServer2的服务端连接进行数据处理
.addHandler(new WebSocketServer2(), "/websocket/api2/**", "/websocket/api3/**")
// WebSocketServer2的握手拦截器处理：尽量避免被无用的请求攻击，在建立连接的时候通过检查授权成功之后才能进行访问
.addInterceptors(new WebSocketAuthInterceptor())
// 允许跨域访问
.setAllowedOrigins("*");
}
}
3.2、配置：WebSocket握手，实现对websocket请求的拦截
package com.chengfu.interceptor;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.HandshakeInterceptor;
import java.util.List;
import java.util.Map;
/**
* websocket握手拦截
*/
@Component
@Slf4j
public class WebSocketAuthInterceptor implements HandshakeInterceptor {
/**
* 返回true允许直接通过，返回false拒绝连接
*
* @param serverHttpRequest
* @param serverHttpResponse
* @param webSocketHandler
* @param map
* @return
* @throws Exception
*/
@Override
public boolean beforeHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Map<String, Object> map) throws Exception {
log.error("握手开始！");
// 确保授权正确才能进行websocket连接
HttpHeaders headers = serverHttpRequest.getHeaders();
List<String> header = headers.get("token");
if (header == null || header.size() == 0) {
return false;
}
String token = header.get(0);
if (StringUtils.isBlank(token)) {
return false;
}
// TODO: token do something
log.error("握手token:{}", token);
return true;
}
@Override
public void afterHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Exception e) {
log.error("握手结束");
}
}
3.3、实现WebSocket服务，监听socket客户端的连接
package com.chengfu.socket;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpHeaders;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;
import java.io.IOException;
import java.time.LocalDateTime;
import java.util.concurrent.ConcurrentHashMap;
// 配合webSocketConfig2使用
@Component
@Slf4j
public class WebSocketServer2 extends TextWebSocketHandler {
/**
* socket 建立成功事件 @OnOpen
*
* @param session
* @throws Exception
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
// websocket入参
// ===============从url上面获取参数
String rawPath = session.getUri().getRawPath(); //
String rawQuery = session.getUri().getRawQuery();// 从url上面获取参数
String query = session.getUri().getQuery(); // 从url上面获取参数
// =================
// ================从header上面获取参数
HttpHeaders headers = session.getHandshakeHeaders(); // 从header上获取参数
// ================
String token = headers.get("token").get(0);
if (token != null) {
WebSocketSession s = WebSessionManager.get(token);
if (s != null) {
// 当前用户之前已经建立连接，关闭
WebSessionManager.remove(token);
}
// 重新建立session
WebSessionManager.add(token, session);
log.error("建立websocket连接：{}", token);
}
}
/**
* 接收消息事件 @OnMessage
*
* @param session
* @param message
* @throws Exception
*/
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
// 获得客户端传来的消息
String payload = message.getPayload();
System.out.println("server 接收到发送的消息 " + payload);
// 服务端发送回去
session.sendMessage(new TextMessage("server 发送消息 " + payload + " " + LocalDateTime.now()));
}
/**
* socket 断开连接时 @OnClose
*
* @param session
* @param status
* @throws Exception
*/
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
Object token = session.getAttributes().get("token");
if (token != null) {
// 用户退出，移除缓存
WebSessionManager.remove(token.toString());
}
}
}
// 来源：https://cssjc.com/img_convert/56bab98ff2681c21fdab8d42f2fb18db.png#averageHue=#f6f5f5&clientId=u9df02626-6c07-4&from=paste&height=185&id=u461d3b36&originHeight=321&originWidth=712&originalType=binary&ratio=1.3499999046325684&rotation=0&showTitle=false&size=19711&status=done&style=none&taskId=u7c1eb9a9-34c8-458d-a67c-a11725abe92&title=&width=410.4028015136719" alt="image.png">
postman请求地址：
建立websocket连接之前，先进行握手处理，检查headers参数之后，如果符合要求，开始建立连接。
拦截发现headers没有token标识，拒绝客户端连接请求，请求头添加token后，重新请求：
检测到token之后，成功建立连接：
参考链接
- SpringBoot使用WebSocket_springboot websocket_仰望银河系的博客-CSDN博客
- Springboot——拦截器_springboot 拦截器_我爱布朗熊的博客-CSDN博客
- 实现Websocket集群及通信的第二种方式（含拦截器）_websockethandler_Second小二的博客-CSDN博客
- springboot整合websocket握手拦截器 - meow_world - 博客园
- Postman 使用 WebSocket 请求_w3cschool
