jee websocket搭建总结

1、使用框架spring+springmvc+mybatis+jdk7+tomcat7+maven

2、基本原理：

　　　　a. WebSocket协议是一种双向通信协议，它建立在TCP之上，同http一样通过TCP来传输数据，但是它和http最大的不同有两点：

1.WebSocket是一种双向通信协议，在建立连接后，WebSocket服务器和Browser/UA都能主动地向对方发送或接收数据，就像Socket一样，不同的是WebSocket是一种建立在Web基础上的一种简单模拟Socket的协议；

2.WebSocket需要通过握手连接，类似于TCP它也需要客户端和服务器端进行握手连接，连接成功后才能相互通信。

　　　　b.struts 和 websocket 是2条处理请求的路，被struts 匹配上了，自然就到不了 websocket的处理逻辑,(http和ws是两种不同的请求协议，注意框架的拦截器（过滤器）)

3、客户端：

<html>

<head>

    <title>Title</title>

    <style>

        div {

            margin-left: auto;

            margin-right: auto;

        }

    </style>

</head>

<body onLoad="startWebSocket()">

<script type="text/javascript">

    function clog(title) {

        console.log(title);

    }

    var ws = null;

    function startWebSocket() {

        if ('WebSocket' in window) {

            try {

                ws = new WebSocket("ws://127.0.0.1:80/websocket/tui");

            } catch (e) {

                clog("1");

            }

        } else if ('MozWebSocket' in window) {

            ws = new MozWebSocket("ws://127.0.0.1:80/websocket/tui");

        } else {

            clog("websocket not support");

        }

        ws.onmessage = function (evt) {

            say(evt.data);

        };

        ws.onclose = function (evt) {

            clog("close!");

        };

        ws.onopen = function (evt) {

            clog("open");

        };

    }

    function sendMsg() {

        ws.send(document.getElementById('writeMsg').value);

    }

    function say(msg) {

        var div = document.createElement("div");

        div.innerHTML = msg;

        document.body.appendChild(div);

    }

</script>

<div onClick="say('d')">WebSocket聊天室</div>

<div style="border:1px solid #09F"></div>

<input type="text" id="writeMsg"/>

<input type="button" value="send" onClick="sendMsg()"/>

</body>

</html>

4、服务端：

@ServerEndpoint(value = "/websocket/tui")

public class WebSocketDemo{

    private static final String GUEST_PREFIX = "Guest";

    private static final AtomicInteger connectionIds = new AtomicInteger(0);

    private static final Set<WebSocketDemo> connections = new HashSet<>();

    private final String nickname;

    private Session session;

    public WebSocketDemo() {

        nickname = GUEST_PREFIX + connectionIds.getAndIncrement();

    }

    //建立连接

    @OnOpen

    public void start(Session session) {

        this.session = session;

        connections.add(this);

        String message = String.format("* %s %s", nickname, "has joined.");

        System.out.println(message);

    }

    //接受消息

    @OnMessage

    public void incoming(String message) {

        System.out.println(message.toString());

        //broadcast(filteredMessage);

        broadcast(message.toString());

    }

    //客户端关闭了连接

    @OnClose

    public void end() {

        connections.remove(this);

        String message = String.format("* %s %s", nickname, "has disconnected.");

        System.out.println(message);

        //broadcast(message);

    }

    //WebSocket服务出错

    @OnError

    public void onError(Throwable t){

        //log.error("Chat Error: " + t.toString(), t);

        System.out.println("server has an error!");

    }

    private static void broadcast(String msg) {

        for (WebSocketDemo client : connections) {

            try {

                synchronized (client) {

                    client.session.getBasicRemote().sendText(msg);

                }

            } catch (IOException e) {

                //log.debug("Chat Error: Failed to send message to client", e);

                connections.remove(client);

                try {

                    client.session.close();

                } catch (IOException e1) {

                    // Ignore

                }

                String message = String.format("* %s %s",

                        client.nickname, "has been disconnected.");

                broadcast(message);

            }

        }

    }

}

注意事项：

1、访问拦截器

2、注意部署的包冲突，例如：javax.websocket只是编译需要，而发布不需要，maven依赖注意适用范围

附：

<!--websocket编译需要，发布不需要-->

<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-coyote -->

<dependency>

    <groupId>org.apache.tomcat</groupId>

    <artifactId>tomcat-coyote</artifactId>

    <version>7.0.12</version>

</dependency>

<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-juli -->

<dependency>

    <groupId>org.apache.tomcat</groupId>

    <artifactId>tomcat-juli</artifactId>

    <version>8.5.3</version>

</dependency>

<!-- https://mvnrepository.com/artifact/javax.websocket/javax.websocket-api -->

<dependency>

    <groupId>javax.websocket</groupId>

    <artifactId>javax.websocket-api</artifactId>

    <version>1.1</version>

    <scope>provided</scope>

</dependency>

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jee websocket搭建总结

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