彗星消息发送两次

时间:2012-01-29 10:36:29

标签: javascript comet dojo cometd bayeux

我想在我的项目中使用Cometd并在Tomcat 7服务器上尝试Jetty 8版本。它可以工作,但邮件正在发送两次。

为了检查它是否与项目的其余部分有关,我设置了一个只有这个功能的独立项目,我仍然收到两次消息。

我无法找出原因。

项目中有5个文件:

  • 的pom.xml
  • 的web.xml
  • 的index.html
  • BayeuxInitializer.java
  • FormDataService.java

以下是每个文件的代码:

  • 的web.xml

     <?xml version="1.0" encoding="UTF-8"?>
     <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee"
              xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
              xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
              id="WebApp_ID" version="2.5">
        <display-name>Sertal Vision</display-name>
    
        <servlet>
           <servlet-name>cometd</servlet-name>
           <servlet-class>org.cometd.server.CometdServlet</servlet-class>
           <init-param>
              <param-name>timeout</param-name>
              <param-value>60000</param-value>
           </init-param>
           <init-param>
              <param-name>logLevel</param-name>
              <param-value>3</param-value>
           </init-param>
           <load-on-startup>1</load-on-startup>
        </servlet>
    
        <servlet>
           <servlet-name>bayeux-init</servlet-name>
           <servlet-class>ch.sertal.server.BayeuxInitializer</servlet-class>
           <load-on-startup>2</load-on-startup>
        </servlet>
    
        <servlet-mapping>
           <servlet-name>cometd</servlet-name>
           <url-pattern>/cometd/*</url-pattern>
        </servlet-mapping>
    
        <servlet-mapping>
           <servlet-name>bayeux-init</servlet-name>
           <url-pattern>/bayeux/servlet/*</url-pattern>
        </servlet-mapping>
    
        <filter>
           <filter-name>continuation</filter-name>
           <filter-class>org.eclipse.jetty.continuation.ContinuationFilter</filter-class>
        </filter>
    
        <filter-mapping>
           <filter-name>continuation</filter-name>
           <url-pattern>/cometd/*</url-pattern>
        </filter-mapping>
    
        <welcome-file-list>
           <welcome-file>index.html</welcome-file>
        </welcome-file-list>
    
     </web-app>
    
  • 的index.html

     <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
     <html>
     <head>
        <meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
        <script type="text/javascript" src="js/dojo/dojo/dojo.js"></script>
        <script type="text/javascript">
           var subscription = undefined;
    
           dojo.addOnLoad( function () {
              dojo.require( "dojox.cometd" );
              dojo.require("dojox.timing");
              // Disconnect when the page unloads
              dojo.addOnUnload( function () {
                 dojox.cometd.disconnect( true );
              } );
    
              var cometURL = "cometd";
              dojox.cometd.init( cometURL );
    
              var subscription = dojox.cometd.subscribe( "/sertal/formData", function ( message ) {
                 dojo.create( "li", {
                    innerHTML:message.data.count
                 }, dojo.byId( "message-list" ) );
              } );
    
              i = 1;
              var t = new dojox.timing.Timer();
              t.setInterval( 1000 );
              t.onTick = function() {
                 dojox.cometd.publish( '/sertal/formData', { count: i++ } );
              };
              t.start();
    
           } );
        </script>
     </head>
     <body>
    
     <div>
        <ul id="message-list"/>
     </div>
     </body>
     </html>
    
  • BayeuxInitializer.java

     package ch.sertal.server;
    
     import org.cometd.bayeux.server.BayeuxServer;
    
     import javax.servlet.GenericServlet;
     import javax.servlet.ServletException;
     import javax.servlet.ServletRequest;
     import javax.servlet.ServletResponse;
     import java.io.IOException;
    
     public class BayeuxInitializer extends GenericServlet {
        private static final long serialVersionUID = -9089442901563633963L;
    
        @Override
        public void init() throws ServletException {
           BayeuxServer bayeux = ( BayeuxServer ) getServletContext().getAttribute( BayeuxServer.ATTRIBUTE );
    
     //      new HelloService( bayeux );
           new FormDataService( bayeux, getServletContext() );
    
        }
    
        @Override
        public void service( ServletRequest servletRequest, ServletResponse servletResponse ) throws ServletException, IOException {
           throw new ServletException( "sorry :-)" );
        }
     }
    
  • FormDataService.java

     package ch.sertal.server;
    
     import org.cometd.bayeux.Message;
     import org.cometd.bayeux.server.BayeuxServer;
     import org.cometd.bayeux.server.ServerSession;
     import org.cometd.server.AbstractService;
    
     import javax.servlet.ServletContext;
     import java.util.Map;
    
     /**
      * Created by IntelliJ IDEA.
      * User: micha.roon
      * Date: 1/16/12
      * Time: 12:25 PM
      * To change this template use File | Settings | File Templates.
      */
     public class FormDataService extends AbstractService {
        private ServletContext context = null;
    
        public FormDataService( BayeuxServer bayeux, ServletContext context ) {
           super( bayeux, "hello" );
           this.context = context;
           addService( "/sertal/formData", "processFormData" );
           System.out.println( "New FormDataService" );
        }
    
        public void processFormData( final ServerSession remote, Message message ) {
           Map<String, Object> input = message.getDataAsMap();
    
           remote.deliver( getServerSession(), "/sertal/formData", input, null );
        }
     }
    
  • 的pom.xml

     <?xml version="1.0" encoding="UTF-8"?>
     <project xmlns="http://maven.apache.org/POM/4.0.0"
              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>BayeuxTest</groupId>
        <artifactId>BayeuxTest</artifactId>
        <version>1.0</version>
    
        <build>
           <plugins>
              <!--compiler plugin-->
              <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                 </configuration>
              </plugin>
    
              <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>tomcat-maven-plugin</artifactId>
                 <version>1.1</version>
                 <configuration>
                    <username>${tomcat.username}</username>
                    <password>${tomcat.password}</password>
                    <url>${tomcat.manager}</url>
                    <path>${tomcat.context}</path>
                 </configuration>
              </plugin>
    
           </plugins>
        </build>
    
        <dependencies>
           <dependency>
              <groupId>javax.servlet</groupId>
              <artifactId>javax.servlet-api</artifactId>
              <version>3.0.1</version>
              <scope>provided</scope>
           </dependency>
    
           <!--for cometd support-->
           <dependency>
              <groupId>org.cometd.java</groupId>
              <artifactId>bayeux-api</artifactId>
              <version>2.3.1</version>
           </dependency>
           <dependency>
              <groupId>org.cometd.javascript</groupId>
              <artifactId>cometd-javascript-jquery</artifactId>
              <version>2.3.1</version>
              <type>war</type>
           </dependency>
           <dependency>
              <groupId>org.cometd.java</groupId>
              <artifactId>cometd-java-server</artifactId>
              <version>2.3.1</version>
           </dependency>
    
           <dependency>
              <groupId>org.eclipse.jetty</groupId>
              <artifactId>jetty-servlets</artifactId>
              <version>8.0.4.v20111024</version>
              <exclusions>
                 <exclusion>
                    <groupId>org.eclipse.jetty</groupId>
                    <artifactId>jetty-client</artifactId>
                 </exclusion>
              </exclusions>
           </dependency>
           <dependency>
              <groupId>javax.servlet</groupId>
              <artifactId>servlet-api</artifactId>
              <version>2.5</version>
           </dependency>
    
        </dependencies>
     </project>
    

1 个答案:

答案 0 :(得分:0)

当您使用普通频道( / sertal / formData )时,所有发布的帖子都将发送给所有订阅的客户端,在您的情况下是浏览器本身和Bayeux服务。因此,您将收到两个答案:一个是您发布的帖子,另一个是您服务的回复。

解决方案:您不希望publish使用formData,您希望deliver编辑:

      ...
      t.onTick = function() {
         dojox.cometd.deliver( '/sertal/formData', { count: i++ } );
      };
      ...

还有其他解决方案,例如使用服务频道而不是普通频道。有关详细说明,请参阅此CometD FAQ Entry

更新:

我保留了另一项必要的更改,以便在我的计算机上执行此操作:dojo.require需要在addOnLoad处理程序之外调用。

     ...   
     dojo.require("dojox.cometd");
     dojo.require("dojox.timing");

     dojo.addOnLoad(function () {
         ...

我一直在使用dojo v1.7.1。