先参照 IntelliJ IDEA 2016.1建立Strut2工程并使用Tomcat调试建立新的工程，一步一步操作，包括最后引用Spring框架部分。
经过上面的操作，Spring-WebSocket的包应该已经被默认引入了，如下图所示：
这就意味着我们已经不需要再进行过多的额外配置了。
接下来，我们在src->Tools下面新建一个WebSocket的目录，里面创建三个Java文件。如下图：
每个文件中的代码如下：
SystemWebSocketHandler.java
package Tools.WebSocket;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;
public class SystemWebSocketHandler extends TextWebSocketHandler {
private static final ArrayList<WebSocketSession> users = new ArrayList<>();
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
System.out.println("ConnectionEstablished");
users.add(session);
session.sendMessage(new TextMessage("connect"));
session.sendMessage(new TextMessage("new_msg"));
}
@Override
public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
System.out.println("handleMessage" + message.toString());
session.sendMessage(new TextMessage(new Date() + ""));
}
@Override
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
if(session.isOpen()){
session.close();
}
users.remove(session);
}
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
users.remove(session);
}
@Override
public boolean supportsPartialMessages() {
return false;
}
/**
* 给所有在线用户发送消息
*
* @param message
*/
public void sendMessageToUsers(TextMessage message) {
for (WebSocketSession user : users) {
try {
if (user.isOpen()) {
user.sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
WebSocketConfig.java
package Tools.WebSocket;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
@Configuration
@EnableWebMvc
@EnableWebSocket
public class WebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {
@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(systemWebSocketHandler(), "/webSocketServer").addInterceptors(new WebSocketHandshakeInterceptor());
}
@Bean
public WebSocketHandler systemWebSocketHandler() {
return new SystemWebSocketHandler();
}
}
WebSocketHandshakeInterceptor.java
package Tools.WebSocket;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.HandshakeInterceptor;
import java.util.Map;
public class WebSocketHandshakeInterceptor implements HandshakeInterceptor {
@Override
public boolean beforeHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Map<String, Object> map) throws Exception {
System.out.println("beforeHandshake");
return true;
}
@Override
public void afterHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Exception e) {
System.out.println("afterHandshake");
}
}
由于我们使用了Struts2导致我们的网络请求优先被Struts2的拦截器拦截，而Struts2又处理不了websocket请求，结果直接返回了404错误。因此我们需要替换掉默认的在web.xml中定义的Struts2的拦截器，要求Struts2不处理websocket请求。
我们在src->Tools下面新建一个Filter的目录,下面创建一个名为StrutsPrepareAndExecuteFilterEx.java的源代码文件，如下图：
具体的代码如下：
StrutsPrepareAndExecuteFilterEx.java
package Tools.Filter;
import org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
public class StrutsPrepareAndExecuteFilterEx extends StrutsPrepareAndExecuteFilter {
@Override
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain filter) throws IOException, ServletException {
String requestURI = ((HttpServletRequest) req).getRequestURI();
if(requestURI != null && (requestURI.contains("/webSocketServer")) || requestURI.startsWith("ws://") || requestURI.contains("/mspjapi"))
filter.doFilter(req, resp);
else
super.doFilter(req, resp, filter);
}
}
这时候的代码是无法编译通过的，原因是依赖的javax的Jar包不存在。此时，我们需要手工引入javax.servlet:javax.servlet-api:3.1.0这个Jar包。如下图：
还要注意，刚刚添加进入的javax.servlet:javax.servlet-api:3.1.0这个Jar包，我们只在编译期间使用，在运行时候，使用Tomcat自己实现的那个同名Jar包。也就是这个包是个Provided，而不是Compile关系，具体如下图：
接下来，修改web.xml指定Struts2的拦截器为我们定义的拦截器
<filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
修改为
<filter> <filter-name>struts2</filter-name> <filter-class>Tools.Filter.StrutsPrepareAndExecuteFilterEx</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
经过上面的修改后，依旧是没办法进行网络访问的，原因是web.xml中的Spring拦截器并没有拦截WebSocket的数据请求。
<servlet> <servlet-name>dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> <async-supported>true</async-supported> </servlet> <servlet-mapping> <servlet-name>dispatcher</servlet-name> <url-pattern>*.form</url-pattern> </servlet-mapping>
修改为
<servlet> <servlet-name>dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> <async-supported>true</async-supported> </servlet> <servlet-mapping> <servlet-name>dispatcher</servlet-name> <url-pattern>*.form</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>dispatcher</servlet-name> <url-pattern>/webSocketServer/*</url-pattern> </servlet-mapping>
注意增加的
<async-supported>true</async-supported>
下一步，配置Spring的配置文件web->WEB-INF->dispatcher-servlet.xml增加配置信息类的扫描目录包含我们刚刚创建的src->Tools->WebSocket的目录（缺少这一步会导致我们通过注解实现的配置信息类没有被自动加载，导致无法访问），修改后的内容如下:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<!-- Scan for spring annotated components -->
<context:component-scan base-package="Tools.WebSocket"/>
</beans>
最后，调用的页面的代码
WebSocket.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>WebSocket</title>
<style type="text/css">
#console-container {
margin-left: 15px;
margin-right: 15px;
padding: 5px;
width: 95%;
}
#console {
border: 1px solid #CCCCCC;
border-right-color: #999999;
border-bottom-color: #999999;
height: 300px;
overflow-y: scroll;
padding: 5px;
width: 100%;
}
#console p {
padding: 0;
margin: 0;
}
</style>
<script type="text/javascript">
var url = 'ws://' + window.location.host + '/webSocketServer';
var ws = new WebSocket(url);
ws.onopen = function () {
log('Info: connection opened.');
};
ws.onmessage = function (event) {
log('Received: ' + event.data);
};
ws.onclose = function (event) {
log('Info: connection closed.');
log(event);
};
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 > 1000) {
console.removeChild(console.firstChild);
}
console.scrollTop = console.scrollHeight;
}
</script>
</head>
<body>
<div>
<div id="console-container">
<div id="console"></div>
</div>
</div>
</body>
</html>
最后的客户端显示效果如下图所示：
注意：如此创建的WebSocket是会在两三分钟后主动断开连接的，原因在于WebSocket需要周期性的发送心跳报文来维持连接。后续我们会尝试使用sockjs来实现自动发送心跳的逻辑。
具体的sockjs的接入方法，参考IntelliJ IDEA 2016.2使用Spring 4.3.1.RELEASE,sockjs-1.1.1,stomp-1.2搭建基于Tomcat-7.0.68的WebSocket应用