基于tomcat的websock+struts2使用

青旅半醒 2022-05-26 01:49 69阅读 0赞

1.需要引入的加包tomcat7-websocket.jar和websocket-api.jar，可以在tomcat自带的lib目录中找到；

2.在web.xml中加入监听

<listener>
    		<listener-class>org.apache.tomcat.websocket.server.WsContextListener</listener-class>
    	</listener>

3.在项目中加入配置类ScanWebSocketSeverConfig.java

import javax.websocket.Endpoint;
    import javax.websocket.server.ServerApplicationConfig;
    import javax.websocket.server.ServerEndpointConfig;
    import java.util.HashSet;
    import java.util.Set;
    
    /**
     * Created by D.chen.g on 2018/4/20.
     */
    public class ScanWebSocketSeverConfig implements ServerApplicationConfig {
    
        @Override
        public Set<ServerEndpointConfig> getEndpointConfigs(Set<Class<? extends Endpoint>> scanned) {
    
            Set<ServerEndpointConfig> result = new HashSet<>();
            return result;
        }
    
        @Override
        public Set<Class<?>> getAnnotatedEndpointClasses(Set<Class<?>> scanned) {
            Set<Class<?>> results = new HashSet<Class<?>>();
            for (Class<?> clazz : scanned) {
    
                if (clazz.getName().equals("com.app.struts.socket.EchoExample")) {//换成你自己websock使用类
                    System.out.println("find end point : " + clazz.getName());
                    results.add(clazz);
                }
            }
            return results;
        }
    
    }

4.在项目中加入使用类EchoExample

import javax.websocket.OnClose;
    import javax.websocket.OnMessage;
    import javax.websocket.OnOpen;
    import javax.websocket.Session;
    import javax.websocket.server.ServerEndpoint;
    import java.io.IOException;
    
    /**
     * Created by D.chen.g on 2018/4/20.
     */
    
    @ServerEndpoint(value = "/echo")
    public class EchoExample {
    
        @OnOpen
        public void openConn(Session session) throws IOException {
            session.getBasicRemote().sendText("hello web socket"); // means open it
        }
    
        @OnClose
        public void onClose(){
            System.out.println(" connection closed ");
        }
    
        @OnMessage
        public void onMessage(String message,Session session)
                throws IOException, InterruptedException
        {
            System.out.println("***************"+message);
            session.getBasicRemote().sendText("  this is  message");
            int sentMessage = 0;
            while(sentMessage < 3){
                Thread.sleep(5000);
                session.getBasicRemote().sendText(" this is one mess " + sentMessage);
                sentMessage++;
            }
            session.getBasicRemote().sendText(" message send over ");
        }
    }

5.在struts.xml中加入过滤

6.前端页面test.html

<html>
    <head>
        <title>Web Socket Echo Test</title>
        <script>
            var ws = null;
            var count = 0;
            function setConnected(connected) {
                document.getElementById('connect').disabled = connected;
                document.getElementById('disconnect').disabled = !connected;
                document.getElementById('echo').disabled  = !connected;
            }
    
            function connect() {
                var target = document.getElementById('target').value;
                if (target == '') {
                    alert('Please select server side connection implementation.');
                    return;
                }
    
                if ('WebSocket' in window) {
                    ws = new WebSocket(target);
                } else if ('MozWebSocket' in window) {
                    ws = new MozWebSocket(target);
                } else {
                    alert('WebSocket is not supported by this browser.');
                    return;
                }
    
                ws.onopen = function () {
                    setConnected(true);
                    log('Info: WebSocket connection opened.');
                };
                ws.onmessage = function (event) {
                    log('Received: ' + event.data);
                    if(event.data instanceof ArrayBuffer)
                    {
                        var bytes = new Uint8Array(event.data);
                        alert(bytes.length + " : " + bytes[0]);
                    }
                };
                ws.onclose = function (event) {
                    setConnected(false);
                    log('Info: WebSocket connection closed, Code: ' + event.code + (event.reason == "" ? "" : ", Reason: " + event.reason));
                };
    
            }
    
            function disconnect() {
                if (ws != null) {
                    ws.doClose();
                    ws = null;
                }
                setConnected(false);
            }
    
            function echo() {
                if (ws != null) {
                    var message = document.getElementById('message').value;
                    log('Sent: ' + message);
                    ws.send(JSON.stringify({'textMessage': message}));
                    count++
                } else {
                    alert('WebSocket connection not established, please connect.');
                }
            }
    
            function log(message) {
                var echomsg = document.getElementById('echomsg');
                var p = document.createElement('p');
                p.style.wordWrap = 'break-word';
                p.appendChild(document.createTextNode(message));
                echomsg.appendChild(p);
                while (echomsg.childNodes.length > 25) {
                    echomsg.removeChild(console.firstChild);
                }
                echomsg.scrollTop = console.scrollHeight;
            }
    
            document.addEventListener("DOMContentLoaded", function() {
                // Remove elements with "noscript" class - <noscript> is not allowed in XHTML
                var noscripts = document.getElementsByClassName("noscript");
                for (var i = 0; i < noscripts.length; i++) {
                    noscripts[i].parentNode.removeChild(noscripts[i]);
                }
            }, false);
        </script>
    </head>
    <body>
    <div>
        
        <h4>URL - ws://localhost:8080/xxx/echo</h4>
        <input id="target" type="text" size="40" style="width: 350px" />
    </div>
    <div>
        <button id="connect" οnclick="connect();">Connect</button>
        <button id="disconnect" disabled="disabled" οnclick="disconnect();">Disconnect</button>
    </div>
    <div>
        <textarea id="message" style="width: 350px">Here is a message!</textarea>
    </div>
    <div>
        <button id="echo" οnclick="echo();" disabled="disabled">Echo message</button>
    </div>
    <div id="echomsg">
    </div>
    </body>
    </html>

7.如果在发布时使用了nginx，前端页面连接请用服务器IP和端口访问websock服务，实测使用域名不行。