spring+websocket整合（springMVC+spring+MyBatis即SSM框架和websocket技術的整合）
阿新 • • 發佈：2019-01-26
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很多小夥伴反映原來的工程無法下載，這個鍋得CSDN背，可能下載量達到一定程度就涉嫌違規了吧。現給出GitHub地址，增強簡化配置版的demo，可能跟下文講的不完全匹配，但原理是一樣的，只不過省去了配置而改用註解。
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spring4.0以後加入了對websocket技術的支援，擼主目前的專案用的是SSM（springMVC+spring+MyBatis）框
架，所以肯定要首選spring自帶的websocket了，好，現在問題來了，擼主在網上各種狂搜猛找，拼湊了幾個自稱是
spring websocket的東東，下來一看，廢物，其中包括從github上down下來的。舉個例子，在搭建過程中有個問題，
擼主上谷歌搜尋，總共搜出來三頁結果共30條左右，前15條是純英文的 後15條是韓語和日語，而這30條結果都不能
解決擼主的問題，無奈，只好上官網看全英幫助，在擼主驚人的毅力和不懈奮鬥下，糾結了兩天的spring+websocket
整合今天算是徹底搭建成功，摸索透徹了。
websocket是目前唯一真正實現全雙工通訊的伺服器向客戶端推的網際網路技術，與長連線和輪詢技術相比，
websocket的優越性不言自明，長連線的連線資源（執行緒資源）隨著連線數量的增多，必會耗盡，客戶端輪詢會給服
務器造成很大的壓力，而websocket是在物理層非網路層建立一條客戶端至伺服器的長連線，以此來保證伺服器向客
戶端的即時推送，既不耗費執行緒資源，又不會不斷向伺服器輪詢請求。
下面言歸正傳，講一講擼主在SSM（springMVC+spring+MyBatis）框架中整合websocket技術的曲折蛋疼直至成功喜悅之路。
- 1 在maven的pom.xml中加入websocket所依賴的jar包，什麼，你不知道maven，快去度之或者檢視擼主關於maven的博文惡補一下，spring-websocket所依賴的jar包有以下幾個：
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.3.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.3.0</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-websocket</artifactId>
<version>4.0.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
<version>4.0.1.RELEASE</version>
</dependency>- 2 更新web.xml中namespace.xsd的版本，
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:websocket="http://www.springframework.org/schema/websocket"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/websocket http://www.springframework.org/schema/websocket/spring-websocket.xsd">- 3 更新spring框架的jar包至4.0以上（spring-core, spring-context, spring-web and spring-webmvc）
<dependency>
<span style="white-space:pre"> </span><groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>- 4 4.1建立websocket處理類
package com.up.websocket.handler;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;
public class WebsocketEndPoint extends TextWebSocketHandler {
@Override
protected void handleTextMessage(WebSocketSession session,
TextMessage message) throws Exception {
super.handleTextMessage(session, message);
TextMessage returnMessage = new TextMessage(message.getPayload()+" received at server");
session.sendMessage(returnMessage);
}
}- 4.2建立握手（handshake）介面
package com.up.websocket;
import java.util.Map;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;
public class HandshakeInterceptor extends HttpSessionHandshakeInterceptor{
@Override
public boolean beforeHandshake(ServerHttpRequest request,
ServerHttpResponse response, WebSocketHandler wsHandler,
Map<String, Object> attributes) throws Exception {
System.out.println("Before Handshake");
return super.beforeHandshake(request, response, wsHandler, attributes);
}
@Override
public void afterHandshake(ServerHttpRequest request,
ServerHttpResponse response, WebSocketHandler wsHandler,
Exception ex) {
System.out.println("After Handshake");
super.afterHandshake(request, response, wsHandler, ex);
}
}- 5 處理類和握手協議的spring配置(applicationContext.xml檔案）
<bean id="websocket" class="com.up.websocket.handler.WebsocketEndPoint"/>
<websocket:handlers>
<websocket:mapping path="/websocket" handler="websocket"/>
<websocket:handshake-interceptors>
<bean class="com.up.websocket.HandshakeInterceptor"/>
</websocket:handshake-interceptors>
</websocket:handlers>- 6 客戶端頁面
<!DOCTYPE html>
<html>
<head>
<title>WebSocket/SockJS Echo Sample (Adapted from Tomcat's echo sample)</title>
<style type="text/css">
#connect-container {
float: left;
width: 400px
}
#connect-container div {
padding: 5px;
}
#console-container {
float: left;
margin-left: 15px;
width: 400px;
}
#console {
border: 1px solid #CCCCCC;
border-right-color: #999999;
border-bottom-color: #999999;
height: 170px;
overflow-y: scroll;
padding: 5px;
width: 100%;
}
#console p {
padding: 0;
margin: 0;
}
</style>
<script src="http://cdn.sockjs.org/sockjs-0.3.min.js"></script>
<script type="text/javascript">
var ws = null;
var url = null;
var transports = [];
function setConnected(connected) {
document.getElementById('connect').disabled = connected;
document.getElementById('disconnect').disabled = !connected;
document.getElementById('echo').disabled = !connected;
}
function connect() {
alert("url:"+url);
if (!url) {
alert('Select whether to use W3C WebSocket or SockJS');
return;
}
ws = (url.indexOf('sockjs') != -1) ?
new SockJS(url, undefined, {protocols_whitelist: transports}) : new WebSocket(url);
ws.onopen = function () {
setConnected(true);
log('Info: connection opened.');
};
ws.onmessage = function (event) {
log('Received: ' + event.data);
};
ws.onclose = function (event) {
setConnected(false);
log('Info: connection closed.');
log(event);
};
}
function disconnect() {
if (ws != null) {
ws.close();
ws = null;
}
setConnected(false);
}
function echo() {
if (ws != null) {
var message = document.getElementById('message').value;
log('Sent: ' + message);
ws.send(message);
} else {
alert('connection not established, please connect.');
}
}
function updateUrl(urlPath) {
if (urlPath.indexOf('sockjs') != -1) {
url = urlPath;
document.getElementById('sockJsTransportSelect').style.visibility = 'visible';
}
else {
if (window.location.protocol == 'http:') {
url = 'ws://' + window.location.host + urlPath;
} else {
url = 'wss://' + window.location.host + urlPath;
}
document.getElementById('sockJsTransportSelect').style.visibility = 'hidden';
}
}
function updateTransport(transport) {
alert(transport);
transports = (transport == 'all') ? [] : [transport];
}
function log(message) {
var console = document.getElementById('console');
var p = document.createElement('p');
p.style.wordWrap = 'break-word';
p.appendChild(document.createTextNode(message));
console.appendChild(p);
while (console.childNodes.length > 25) {
console.removeChild(console.firstChild);
}
console.scrollTop = console.scrollHeight;
}
</script>
</head>
<body>
<noscript><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websockets
rely on Javascript being enabled. Please enable
Javascript and reload this page!</h2></noscript>
<div>
<div id="connect-container">
<input id="radio1" type="radio" name="group1" onclick="updateUrl(''/spring-websocket-uptest/websocket');">
<label for="radio1">W3C WebSocket</label>
<br>
<input id="radio2" type="radio" name="group1" onclick="updateUrl('/spring-websocket-uptest/websocket');">
<label for="radio2">SockJS</label>
<div id="sockJsTransportSelect" style="visibility:hidden;">
<span>SockJS transport:</span>
<select onchange="updateTransport(this.value)">
<option value="all">all</option>
<option value="websocket">websocket</option>
<option value="xhr-polling">xhr-polling</option>
<option value="jsonp-polling">jsonp-polling</option>
<option value="xhr-streaming">xhr-streaming</option>
<option value="iframe-eventsource">iframe-eventsource</option>
<option value="iframe-htmlfile">iframe-htmlfile</option>
</select>
</div>
<div>
<button id="connect" onclick="connect();">Connect</button>
<button id="disconnect" disabled="disabled" onclick="disconnect();">Disconnect</button>
</div>
<div>
<textarea id="message" style="width: 350px">Here is a message!</textarea>
</div>
<div>
<button id="echo" onclick="echo();" disabled="disabled">Echo message</button>
</div>
</div>
<div id="console-container">
<div id="console"></div>
</div>
</div>
</body>
</html>- 7 按照以上步驟搭建，根據個人開發環境不同，可能會出現各種問題，下面將在整個搭建過程中遇到的問題總結一下，詳見博文：http://blog.csdn.net/gisredevelopment/article/details/38397569