我的GWT RPC AsyncCallback不起作用：InvocationException [英] My GWT RPC AsyncCallback doesn’t work: InvocationException

问题描述

我开发了一个GWT应用程序，并在服务器端生成一个jfreechart的AsyncCallback。但是返回InvocationException时出错。
详细的错误信息在这里
404 html
com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived（RequestCallbackAdapter.java:209）
callback。 onResponseReceived（this，response）;

我使用了GWT 2.5.1和jre7和eclipse juno 4.2
我的服务接口，异步接口和实现服务代码是与此示例相同
http：//www.jfree .org / phpBB2 / viewtopic.php？t = 19080& sid = f627bee2b70f0f512009d737957b8eee

我在我的web.xml中添加了servlet

 < servlet> 
< servlet-name> ChartGenerator< / servlet-name> 
< servlet-class> com.test.server.ChartGeneratorImpl< / servlet-class> 
< / servlet> 
 
< servlet> 
< servlet-name> DisplayChart< / servlet-name> 
< servlet-class> org.jfree.chart.servlet.DisplayChart< / servlet-class> 
< / servlet> 
 
< servlet-mapping> 
< servlet-name> ChartGenerator< / servlet-name> 
< url-pattern> / comp / ChartGenerator< / url-pattern> 
< / servlet-mapping> 
 
< servlet-mapping> 
< servlet-name> DisplayChart< / servlet-name> 
< url-pattern> / comp / DisplayChart< / url-pattern> 
< / servlet-mapping> 
  

我检查了RPC的文档，它说
InvocationException可能发生的原因很多：网络可能会断开连接，DNS服务器可能不可用，HTTP服务器可能未在监听等等。
我的互联网运行良好。
任何建议？

非常感谢！
Helen

解决方案

1. web.xml中定义的url模式中的前缀/ context_root 。在你的情况下，url模式将是/ comp / ChartGenerator。
   
2. 在RemoteService接口中使用注释@RemoteServiceRelativePath（ChartGenerator）。
   

>

I developed a GWT application and make a AsyncCallback a jfreechart generated in server side. But there is an error returning a InvocationException. The detailed error message is here 404 html com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:209) callback.onResponseReceived(this, response);

I used GWT 2.5.1 and jre7 and eclipse juno 4.2 My Service Interface, Asynchronous Interface and Implementing Service codes are the same as this example http://www.jfree.org/phpBB2/viewtopic.php?t=19080&sid=f627bee2b70f0f512009d737957b8eee

I have added servlet in my web.xml

<servlet>
<servlet-name>ChartGenerator</servlet-name>
<servlet-class>com.test.server.ChartGeneratorImpl</servlet-class>
</servlet>

<servlet>
    <servlet-name>DisplayChart</servlet-name>
    <servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>ChartGenerator</servlet-name>
    <url-pattern>/comp/ChartGenerator</url-pattern>
</servlet-mapping>

<servlet-mapping>
    <servlet-name>DisplayChart</servlet-name>
    <url-pattern>/comp/DisplayChart</url-pattern>
</servlet-mapping>

I checked the documentation of RPC and it said InvocationException can happen for many reasons: the network may be disconnected, a DNS server might not be available, the HTTP server might not be listening, and so on. My internet is working well. Any suggestion?
Many thanks! Helen

解决方案

1. Prefix "/context_root" in url pattern defined in web.xml. In your case the url pattern will be "/comp/ChartGenerator".
2. Use annotation @RemoteServiceRelativePath("ChartGenerator") in RemoteService interface.

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