Dwr的Reverse Ajax可分为两中基本的mode.一种是Active,另一种是Passive,在Active中又分为三种.
Full Streaming Mode
Early Closing Mode
Polling Mode
在DWR应用中.默认启用的是Full Streaming Mode .它是三种modes中最快的一种.它每60秒检查一次浏览器是否是活跃的.配置很简单:
<servlet>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<init-param>
<param-name>activeReverseAjaxEnabled</param-name>
<param-value>true</param-value>
</init-param>
</servlet>
然后在要使用Reverse Ajax的页面使用
dwr.engine.setActiveReverseAjax(true);
即可...在2.0.4以后的版本中还要加入
<init-param>
<param-name>maxWaitAfterWrite</param-name>
<param-value>-1</param-value>
</init-param>
因为在2.0.4版本中默认是使用Early Closing Mode
Early Closing Mode:
在2.0.4以后的版本中不需要添加配置..而2.0.3以前的版本需要、添加
<init-param>
<param-name>maxWaitAfterWrite</param-name>
<param-value>500</param-value>
</init-param>
If it is deemed unwise to hold connections open at all then DWR can use polling mode
<init-param>
<param-name>org.directwebremoting.extend.ServerLoadMonitor</param-name>
<param-value>org.directwebremoting.impl.PollingServerLoadMonitor</param-value>
</init-param>
In polling mode the default poll rate is every 5 seconds. This can be customized using the following:
<init-param>
<param-name>disconnectedTime</param-name>
<param-value>60000</param-value>
</init-param>
The example above will poll only once every 60 seconds (60,000 milliseconds). For many applications a response time of 60 seconds will be enough, and will allow a web server to handle a very large number of clients.
测试环境:IE8.0,Firefox 2.0,Windows xp sp2,Tomcat 6.0,MsSQL Server 2000
使用技术:Spring,Hibernate.Ext.DWR
用第一种配置的时候IE运行不了.报异常 "要完成操作的数据尚未准备好",Firefox可以.
第二种配置在maxWaitForWrite少于200的情况下IE运行正常,Firefox运行正常.
第三种配置只能打开一个连接.再想打开第二个则会报 java.lang.IllegaStateException:Cannot create a session after response has been commited
很是郁闷...若将maxWaitForWrite设置为100.则两个浏览器均没问题..但是浏览器久无刷新动作就无法从服务器调用客户端
这篇文章望抛砖引玉..各位讲下你们是如何配置的
参考资料:http://getahead.org/dwr/reverse-ajax/configuration
posted on 2008-06-15 01:30
phyeas 阅读(1032)
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