 <!--spring webSocket 的依赖包 -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-websocket</artifactId>
    <version>5.1.3.RELEASE</version>
</dependency>

二、spring websocket

2.1 创建消息处理类，继承自TextWebSocketHandler

/**
 * @author : heibaiying
 * @description : 自定义消息处理类
 */
public class CustomHandler extends TextWebSocketHandler {

    private Map<String, WebSocketSession> nameAndSession = new ConcurrentHashMap<>();

    // 建立连接时候触发
    @Override
    public void afterConnectionEstablished(WebSocketSession session)  {
        String username = getNameFromSession(session);
        nameAndSession.putIfAbsent(username, session);
    }


    // 关闭连接时候触发
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
        String username = getNameFromSession(session);
        nameAndSession.remove(username);
    }

    // 处理消息
    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        // 防止中文乱码
        String msg = URLDecoder.decode(message.getPayload(), "utf-8");
        String username = getNameFromSession(session);
        // 简单模拟群发消息
        TextMessage reply = new TextMessage(username + " : " + msg);
        nameAndSession.forEach((s, webSocketSession)
                -> {
            try {
                webSocketSession.sendMessage(reply);
            } catch (IOException e) {
                e.printStackTrace();
            }
        });
    }


    private String getNameFromSession(WebSocketSession session) {
        Map<String, Object> attributes = session.getAttributes();
        return (String) attributes.get(Constant.USER_NAME);
    }
}

2.2 创建websocket 握手拦截器（如果没有权限拦截等需求，这一步不是必须的）

/**
 * @author : heibaiying
 * @description : 可以按照需求实现权限拦截等功能
 */
public class CustomHandshakeInterceptor extends HttpSessionHandshakeInterceptor {

    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
        InetSocketAddress remoteAddress = request.getRemoteAddress();
        InetAddress address = remoteAddress.getAddress();
        System.out.println(address);
        /*
         * 最后需要要显示调用父类方法，父类的beforeHandshake方法
         * 把ServerHttpRequest 中session中对应的值拷贝到WebSocketSession中。
         * 如果我们没有实现这个方法，我们在最后的handler处理中 是拿不到 session中的值
         * 作为测试 可以注释掉下面这一行 可以发现自定义处理器中session的username总是为空
         */
        return super.beforeHandshake(request, response, wsHandler, attributes);
    }
}

2.3 创建websocket的配置类

/**
 * @author : heibaiying
 * @description :websocket 配置
 */
@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(new CustomHandler(), "/socket").addInterceptors(new CustomHandshakeInterceptor());
    }
}

2.4 前端 websocket 的实现

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>${sessionScope.get("username")}您好！欢迎进入群聊大厅！</title>
</head>
<body>
<input id="message" type="text">
<button id="btn">发送消息</button>
<div id="show">

</div>
<script>
    let btn = document.getElementById("btn");
    let message = document.getElementById("message");
    let show = document.getElementById("show");
    let ws = new WebSocket("ws://localhost:8080/socket");
    ws.onmessage = function (evt) {
        let node = document.createElement("div");
        node.innerHTML = "<h5>" + evt.data + "</h5>";
        show.appendChild(node);
    };
    btn.addEventListener("click", function () {
        let data = message.value;
        console.log(data);
        if (data) {
            ws.send(encodeURI(data));
        } else {
            alert("请输入消息后发送");
        }
        message.value = "";
    });
    // 关闭页面时候关闭ws
    window.addEventListener("beforeunload", function(event) {
        ws.close();
    });
</script>
</body>
</html>

2.5 简单登录的实现

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/login" method="post">
    <input name="username" type="text">
    <button id="btn">输入临时用户名后登录！</button>
</form>
</body>
</html>

@Controller
public class LoginController {

    @PostMapping("login")
    public String login(String username, HttpSession session){
        session.setAttribute(Constant.USER_NAME,username);
        return "chat";
    }
}

README.md Unescape Escape

spring websocket（注解方式）

目录

正文

一、说明

1.1 项目结构说明

1.2 依赖说明

二、spring websocket

2.1 创建消息处理类，继承自TextWebSocketHandler

2.2 创建websocket 握手拦截器（如果没有权限拦截等需求，这一步不是必须的）

2.3 创建websocket的配置类

2.4 前端 websocket 的实现

2.5 简单登录的实现

README.md