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什么是WebSocket

WebSocket 是一种网络通信协议，很多高级功能都需要它。

详细的WebSocket可以参考阮一峰的博客 ：http://www.ruanyifeng.com/blog/2017/05/websocket.html

Maven 依赖

       
    
     org.springframework.boot
        
    
     spring-boot-starter-websocket
    
   

SpringBoot配置

import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.web.socket.server.standard.ServerEndpointExporter;/** * Created with IntelliJ IDEA. * * @Auther: zlf * @Date: 2021/04/30/16:58 * @Description: */@Configuration//@EnableWebSocketMessageBrokerpublic class WebSocketConfig {       @Bean    public ServerEndpointExporter serverEndpointExporter(){           return new ServerEndpointExporter();    }}

WebSokect 通信

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.Objects;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.CopyOnWriteArraySet;/** * Created with IntelliJ IDEA. * * @Auther: zlf * @Date: 2021/04/30/17:48 * @Description: */@Slf4j@ServerEndpoint("/webSocket/{code}")@Componentpublic class WebSocketServer {       /**     * 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
   
     webSocketSet = new CopyOnWriteArraySet<>();    /**     * 与客户端的连接会话，需要通过它来给客户端发送数据     */    private Session session;    /**     * 接收识别码     */    private String code = "";    /**     * 连接建立成功调用的方法     */    @OnOpen    public void onOpen(Session session, @PathParam("code") String code) {           this.session = session;        //如果存在就先删除一个，防止重复推送消息，实际这里实现了set，不删除问题也不大        webSocketSet.removeIf(webSocket -> webSocket.code.equals(code));        webSocketSet.add(this);        this.code = code;        log.info("建立WebSocket连接，code：" + code+"，当前连接数："+webSocketSet.size());    }    /**     * 连接关闭调用的方法     */    @OnClose    public void onClose() {           webSocketSet.remove(this);        log.info("关闭WebSocket连接，code：" + this.code+"，当前连接数："+webSocketSet.size());    }    /**     * 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("收到来[" + code + "]的信息:" + message);    }    @OnError    public void onError(Session session, Throwable error) {           log.error("websocket发生错误");        error.printStackTrace();    }    /**     * 实现服务器主动推送     */    private void sendMessage(String message) throws IOException {           this.session.getBasicRemote().sendText(message);    }    /**     * 群发自定义消息     */    public void sendAll(String message) {           log.info("推送消息到" + code + "，推送内容:" + message);        for (WebSocketServer item : webSocketSet) {               try {                   item.sendMessage(message);            } catch (IOException e) {                   e.printStackTrace();            }        }    }    /**     * 定点推送     */    public void sendTo(String message, @PathParam("code") String code) {           for (WebSocketServer item : webSocketSet) {               try {                   if (item.code.equals(code)) {                       log.info("推送消息到[" + code + "]，推送内容:" + message);                    item.sendMessage(message);                }            } catch (IOException e) {                   e.printStackTrace();            }        }    }    @Override    public boolean equals(Object o) {           if (this == o) {               return true;        }        if (o == null || getClass() != o.getClass()) {               return false;        }        WebSocketServer that = (WebSocketServer) o;        return Objects.equals(session, that.session) &&                Objects.equals(code, that.code);    }    @Override    public int hashCode() {           return Objects.hash(session, code);    }}
   

这样前端发起相应的请求就可以建立双向的通信。

#前端Vue代码

关于权限认证

import com.baomidou.mybatisplus.core.toolkit.StringUtils;import com.youshe.mcp.utils.JwtTokenUtil;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Value;import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;import org.springframework.security.core.GrantedAuthority;import org.springframework.security.core.authority.SimpleGrantedAuthority;import org.springframework.security.core.context.SecurityContextHolder;import org.springframework.security.core.userdetails.UserDetails;import org.springframework.security.core.userdetails.UsernameNotFoundException;import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;import org.springframework.stereotype.Component;import org.springframework.web.filter.OncePerRequestFilter;import javax.servlet.FilterChain;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.util.ArrayList;import java.util.List;/** * @Description: JWT登录授权过滤器 * @Author: zlf * @Date: 2021/3/30 */@Component@Slf4jpublic class JwtAuthenticationTokenFilter extends OncePerRequestFilter {       @Autowired    private JwtTokenUtil jwtTokenUtil;    @Value("${jwt.tokenHeader}")    private String tokenHeader;    @Value("${jwt.tokenHead}")    private String tokenHead;    @Autowired    private MyUserDetailsService userDetailsService;    @Override    protected void doFilterInternal(HttpServletRequest request,                                    HttpServletResponse response,                                    FilterChain chain) throws ServletException, IOException {           String authHeader = request.getHeader(this.tokenHeader);        if(StringUtils.isBlank(authHeader)){           	// 由于webSocket 没有设置token在请求头里，而在url中            // websocket连接时，令牌放在url参数上，            authHeader = request.getParameter(this.tokenHeader);        }        if (authHeader != null && authHeader.startsWith(this.tokenHead)) {               String authToken = authHeader.substring(this.tokenHead.length());// The part after "Bearer "            String username = jwtTokenUtil.getUserNameFromToken(authToken);            //log.info("checking username:{}", username);            if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {                   UserDetails userDetails = userDetailsService.loadUserByUsername(username);                if (jwtTokenUtil.validateToken(authToken, userDetails)) {                       UsernamePasswordAuthenticationToken authentication = new UsernamePasswordAuthenticationToken(userDetails, new BCryptPasswordEncoder().encode(userDetails.getPassword()), userDetails.getAuthorities());                    authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));                    //log.info("authenticated user:{}", username);                    SecurityContextHolder.getContext().setAuthentication(authentication);                }            }        }        chain.doFilter(request, response);    }}

测试

import com.youshe.commonutils.vo.ResultVo;import com.youshe.mcp.entity.User;import com.youshe.mcp.service.UserService;import com.youshe.mcp.service.WebSocketServer;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.security.core.Authentication;import org.springframework.security.core.context.SecurityContextHolder;import org.springframework.security.core.userdetails.UserDetails;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import springfox.documentation.annotations.ApiIgnore;import sun.plugin.liveconnect.SecurityContextHelper;import javax.xml.transform.Result;import java.security.Security;/** * Created with IntelliJ IDEA. * * @Auther: zlf * @Date: 2021/04/30/18:03 * @Description: */@RestController@RequestMapping("/test")public class testController {       @Autowired    UserService userService;    @Autowired    WebSocketServer webSocketServer;	// 向请求的用户 推送消息    @GetMapping("test")    public ResultVo test(){           UserDetails userDetails = (UserDetails) org.springframework.security.core.context.SecurityContextHolder.getContext().getAuthentication().getPrincipal();        String username = userDetails.getUsername();        User user = userService.getUserByName(username);        webSocketServer.sendTo("向客户端推送实时消息",user.getId());        return ResultVo.ok();    }}

效果