@Controller
public class UserChatController {

    @Autowired
    private WebSocketService ws;

    /**
     * 1、登陆时，模拟数据库的用户信息
     */
    //模拟数据库用户的数据
    public static Map<String, String> userMap = new HashMap<String, String>();
    static{
        userMap.put("zhangsan", "123");
        userMap.put("lisi", "456");
        userMap.put("wangwu", "789");
        userMap.put("zhaoliu", "000");
        userMap.put("xiaoxiao", "666");
    }

    /**
     *2、 模拟用户在线进行页面跳转的时候，判断是否在线
     * (这个实际开发中肯定存在redis或者session中,这样数据才能共享）
     * 这里只是简单的做个模拟，所以暂且用普通map吧
     */
    public static Map<String, User> onlineUser = new HashMap<>();
    static{
        //key值一般是每个用户的sessionID（这里表示admin用户一开始就在线）
        onlineUser.put("123",new User("admin","888"));
    }
    
    
    /**
     *3、 功能描述：用户登录接口
     */
    @RequestMapping(value="login", method=RequestMethod.POST)
    public String userLogin( @RequestParam(value="username", required=true)String username, 
            @RequestParam(value="pwd",required=true) String pwd, HttpSession session) {

        //判断是否正确
        String password = userMap.get(username);
        if (pwd.equals(password)) {
            User user = new User(username, pwd);
            String sessionId = session.getId();

            //用户登陆成功就把该用户放到在线用户中...
            onlineUser.put(sessionId, user);
            //跳到群聊页面
            return "redirect:/group/chat.html";
        } else {
            return "redirect:/group/error.html";
        }
        
    }
    
    /**
     *4、 功能描述：用于定时给客户端推送在线用户
     */
    @Scheduled(fixedRate = 2000)
    public void onlineUser() {
        ws.sendOnlineUser(onlineUser);
    }
    
    /**
     *5、 功能描述 群聊天接口
     * message 消息体
     * headerAccessor 消息头访问器，通过这个获取sessionId
     */
    @MessageMapping("/group/chat")
    public void topicChat(InMessage message, SimpMessageHeaderAccessor headerAccessor){
        //这个sessionId是在HttpHandShakeIntecepter拦截器中放入的
        String sessionId = headerAccessor.getSessionAttributes().get("sessionId").toString();
        //通过sessionID获得在线用户信息
        User user = onlineUser.get(sessionId);
        message.setFrom(user.getUsername());
        ws.sendTopicChat(message);
        
    }    
}

/**
 * WebSocket握手请求的拦截器. 检查握手请求和响应, 对WebSocketHandler传递属性
 * 可以通过这个类的方法获取resuest,和response
 */
public class HttpHandShakeIntecepter implements HandshakeInterceptor{


    //在握手之前执行该方法, 继续握手返回true, 中断握手返回false. 通过attributes参数设置WebSocketSession的属性
    //这个项目只在WebSocketSession这里存入sessionID
    @Override
    public boolean beforeHandshake(ServerHttpRequest request,
            ServerHttpResponse response, WebSocketHandler wsHandler,
            Map<String, Object> attributes) throws Exception {

        System.out.println("【握手拦截器】beforeHandshake");

        if(request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest)request;
            HttpSession session =  servletRequest.getServletRequest().getSession();
            String sessionId = session.getId();
            System.out.println("【握手拦截器】beforeHandshake sessionId="+sessionId);
            //这里将sessionId放入SessionAttributes中，
            attributes.put("sessionId", sessionId);
        }
        
        return true;
    }
 
    //在握手之后执行该方法. 无论是否握手成功都指明了响应状态码和相应头(这个项目没有用到该方法）
    @Override
    public void afterHandshake(ServerHttpRequest request,
            ServerHttpResponse response, WebSocketHandler wsHandler,
            Exception exception) {
        System.out.println("【握手拦截器】afterHandshake");
        
        if(request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest)request;
            HttpSession session =  servletRequest.getServletRequest().getSession();
            String sessionId = session.getId();
            System.out.println("【握手拦截器】afterHandshake sessionId="+sessionId);
        }
    }
}

/** 
 * 功能描述：频道拦截器 ，类似管道，可以获取消息的一些meta数据
 */
public class SocketChannelIntecepter extends ChannelInterceptorAdapter{

    /**
     * 在完成发送之后进行调用，不管是否有异常发生，一般用于资源清理
     */
    @Override
    public void afterSendCompletion(Message<?> message, MessageChannel channel,
            boolean sent, Exception ex) {
        System.out.println("SocketChannelIntecepter->afterSendCompletion");
        super.afterSendCompletion(message, channel, sent, ex);
    }

    
    /**
     * 在消息被实际发送到频道之前调用
     */
    @Override
    public Message<?> preSend(Message<?> message, MessageChannel channel) {
        System.out.println("SocketChannelIntecepter->preSend");
        
        return super.preSend(message, channel);
    }

    /**
     * 发送消息调用后立即调用
     */
    @Override
    public void postSend(Message<?> message, MessageChannel channel,
            boolean sent) {
        System.out.println("SocketChannelIntecepter->postSend");
        
        StompHeaderAccessor headerAccessor = StompHeaderAccessor.wrap(message);//消息头访问器
        
        if (headerAccessor.getCommand() == null ) return ;// 避免非stomp消息类型，例如心跳检测
        
        String sessionId = headerAccessor.getSessionAttributes().get("sessionId").toString();
        System.out.println("SocketChannelIntecepter -> sessionId = "+sessionId);
        
        switch (headerAccessor.getCommand()) {
        case CONNECT:
            connect(sessionId);
            break;
        case DISCONNECT:
            disconnect(sessionId);
            break;
        case SUBSCRIBE:    
            break;
        
        case UNSUBSCRIBE:
            break;
        default:
            break;
        }
    }

    /**
     * 连接成功
     */
    private void connect(String sessionId){
        System.out.println("connect sessionId="+sessionId);
    }

    /**
     * 断开连接
     */
    private void disconnect(String sessionId){
        System.out.println("disconnect sessionId="+sessionId);
        //用户下线操作
        UserChatController.onlineUser.remove(sessionId);
    }
    
}

@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {


    /**
     *配置基站
     */
    public void registerStompEndpoints(StompEndpointRegistry registry) {

        registry.addEndpoint("/endpoint-websocket").addInterceptors(new HttpHandShakeIntecepter()).setAllowedOrigins("*").withSockJS();
    }

    /**
     * 配置消息代理(中介)
     * enableSimpleBroker 服务端推送给客户端的路径前缀
     * setApplicationDestinationPrefixes  客户端发送数据给服务器端的一个前缀
     */
    @Override
    public void configureMessageBroker(MessageBrokerRegistry registry) {

        registry.enableSimpleBroker("/topic","/chat");
        registry.setApplicationDestinationPrefixes("/app");

    }

  
    @Override
    public void configureClientInboundChannel(ChannelRegistration registration) {
        registration.interceptors( new SocketChannelIntecepter());
    }

    @Override
    public void configureClientOutboundChannel(ChannelRegistration registration) {
        registration.interceptors( new SocketChannelIntecepter());
    }

}

var stompClient = null;

//一加载就会调用该方法
function connect() {
    var socket = new SockJS(‘/endpoint-websocket‘);
    stompClient = Stomp.over(socket);
    stompClient.connect({}, function (frame) {
        setConnected(true);
        console.log(‘Connected: ‘ + frame);
        
        //订阅群聊消息
        stompClient.subscribe(‘/topic/chat‘, function (result) {
            showContent(JSON.parse(result.body));
        });
        
        //订阅在线用户消息
        stompClient.subscribe(‘/topic/onlineuser‘, function (result) {
            showOnlieUser(JSON.parse(result.body));
        });
        
        
    });
}


//断开连接
function disconnect() {
    if (stompClient !== null) {
        stompClient.disconnect();
    }
    setConnected(false);
    console.log("Disconnected");
}

//发送聊天记录
function sendContent() {
    stompClient.send("/app/group/chat", {}, JSON.stringify({‘content‘: $("#content").val()}));
    
}

//显示聊天记录
function showContent(body) {
    $("#record").append("<tr><td>" + body.content + "</td> <td>"+new Date(body.time).toLocaleTimeString()+"</td></tr>");
}

//显示实时在线用户
function showOnlieUser(body) {
    $("#online").html("<tr><td>" + body.content + "</td> <td>"+new Date(body.time).toLocaleTimeString()+"</td></tr>");
}


$(function () {
    
    connect();//自动上线
    
    $("form").on(‘submit‘, function (e) {
        e.preventDefault();
    });
     
    $( "#disconnect" ).click(function() { disconnect(); });
    $( "#send" ).click(function() {
        sendContent(); 
    });
});