does not contain specified method (check logs)

Action[/***] does not contain specified method (check logs)

今天利用SS1H框架整合做练习的时候，出现了一个Action中没有包含指定方法的Exception

异常信息：

2011-8-18 20:50:07 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NoSuchMethodException: Action[/userAction] does not contain specified method (check logs)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:261)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
at org.springframework.web.struts.DelegatingActionProxy.execute(DelegatingActionProxy.java:113)
at org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
at org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)

想到了是自定义Action类中的方法调用时出现了问题。

从头到尾检查了N遍配置文件以及页面调用传参等代码块都未发现问题。。

许久后终于……

错误代码：

public ActionForward doQuery(ActionMapping mapping, ActionForm form,
ServletRequest request, ServletResponse response) throws Exception {

//内部实现略

}

原来问题出在方法的参数中。这也怪自己偷鸡不成蚀把米。

本想偷懒一下，直接利用重写DispatchAction类中的execute方法，改一下名字后直接使用。

没想到，粗心选错，重写了Action类中的execute，结果可想而知。。。

解决方案：

public ActionForward doQuery(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) throws Exception {

//内部实现略

}

顺便分享一下出现此异常的其他几种情况：

1、自定义Action类需要继承DispatchAction类。

2、方法参数ActionMapping mapping, ActionForm form,

HttpServletRequest request,
HttpServletResponse response 顺序也需一致。

3、方法的访问修饰符设置为public、不是protected，更不是其他。

4、动态调用Action，在struts-config.xml中要配置Action的parameter参数，

参数是页面传值的参数，值与要执行Action中的方法名相同。

<action-mappings >
<action
path="/userAction"
type="org.springframework.web.struts.DelegatingActionProxy"
name="userForm"
parameter="method" >
<forward name="success" path="/index.jsp"></forward>
<forward name="error" path="/error.jsp"></forward>
</action>
</action-mappings>

<html:form action="${pageContext.request.contextPath}/userAction.do?method=doQuery" method="post">
Name:<html:text property="user.fname"></html:text>
Area:<html:text property="user.farea"></html:text>
<html:submit value="Search Flowers"></html:submit>
</html:form>

5、页面表单提交方式为post，否则也有可能出现这种异常。