大家帮忙看下：一个简单的Struts 错在哪里？

Question

/////////////////////////////////////struts-config.xml////////////////////
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.1//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd">
<struts-config>
  <form-beans>
    <form-bean name="login3Form" type="login3.login3Form" />
  </form-beans>
  <action-mappings>
    <action input="/login3.jsp" name="login3Form" path="/login3Action" scope="request" type="login3.login3Action" validate="true">
      <forward name="err" path="/err.jsp" />
    </action>
  </action-mappings>
</struts-config>/////////////////////////////错误提示/////////////////////////////////////////
信息: Initializing Coyote HTTP/1.1 on http-8083Starting service Tomcat-StandaloneApache Tomcat/4.1.31HostConfig[localhost]: Deploying configuration descriptor jb-WebModule2.xmlWebappLoader[/WebModule2]: Deploying class repositories to work directory D:\j2eeDemo\login3\Tomcat\work\WebModule2WebappLoader[/WebModule2]: Deploy class files /WEB-INF/classes to D:\j2eeDemo\login3\WebModule2\WEB-INF\classesWebappLoader[/WebModule2]: Deploy JAR /WEB-INF/lib/struts.jar to D:\j2eeDemo\login3\WebModule2\WEB-INF\lib\struts.jarWebappLoader[/WebModule2]: Reloading checks are enabled for this ContextStandardManager[/WebModule2]: Seeding random number generator class java.security.SecureRandomStandardManager[/WebModule2]: Seeding of random number generator has been completedStandardWrapper[/WebModule2:default]: Loading container servlet defaultStandardWrapper[/WebModule2:action]: Marking servlet action as unavailableStandardContext[/WebModule2]: Servlet /WebModule2 threw load() exception: javax.servlet.ServletException: Error instantiating servlet class org.apache.struts.action.ActionServletjavax.servlet.ServletException: Error instantiating servlet class org.apache.struts.action.ActionServlet at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:865) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:776) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3363) at org.apache.catalina.core.StandardContext.start(StandardContext.java:3586) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:774) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:760) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:548) at org.apache.catalina.core.StandardHostDeployer.addChild(StandardHostDeployer.java:653) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:324) at org.apache.commons.beanutils.MethodUtils.invokeMethod(MethodUtils.java:252) at org.apache.commons.digester.SetNextRule.end(SetNextRule.java:256) at org.apache.commons.digester.Rule.end(Rule.java:276) at org.apache.commons.digester.Digester.endElement(Digester.java:1058) at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source) at org.apache.xerces.parsers.AbstractXMLDocumentParser.emptyElement(Unknown Source) at org.apache.xerces.impl.dtd.XMLDTDValidator.emptyElement(Unknown Source) at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source) at org.apache.xerces.impl.XMLDocumentScannerImpl$ContentDispatcher.scanRootElementHook(Unknown Source) at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source) at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source) at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source) at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source) at org.apache.xerces.parsers.XMLParser.parse(Unknown Source) at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source) at org.apache.commons.digester.Digester.parse(Digester.java:1567) at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:338) at org.apache.catalina.core.StandardHost.install(StandardHost.java:772) at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:395) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:352) at org.apache.catalina.startup.HostConfig.start(HostConfig.java:671) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1149) at org.apache.catalina.core.StandardHost.start(StandardHost.java:707) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1141) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:316) at org.apache.catalina.core.StandardService.start(StandardService.java:450) at org.apache.catalina.core.StandardServer.start(StandardServer.java:2143) at org.apache.catalina.startup.Catalina.start(Catalina.java:463) at org.apache.catalina.startup.Catalina.execute(Catalina.java:350) at org.apache.catalina.startup.Catalina.process(Catalina.java:129) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:324) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:156)StandardWrapper[/WebModule2:invoker]: Loading container servlet invokerCoyoteConnector Coyote can't register jmx for protocol2005-12-26 23:59:32 org.apache.coyote.http11.Http11Protocol start信息: Starting Coyote HTTP/1.1 on http-80832005-12-26 23:59:39 org.apache.struts.util.PropertyMessageResources <init>信息: Initializing, config='org.apache.struts.util.LocalStrings', returnNull=true2005-12-26 23:59:39 org.apache.struts.util.PropertyMessageResources <init>信息: Initializing, config='org.apache.struts.taglib.html.LocalStrings', returnNull=true2005-12-26 23:59:39 org.apache.struts.util.PropertyMessageResources <init>信息: Initializing, config='org.apache.struts.util.LocalStrings', returnNull=true2005-12-26 23:59:39 org.apache.struts.util.PropertyMessageResources <init>信息: Initializing, config='org.apache.struts.taglib.html.LocalStrings', returnNull=trueStandardWrapperValve[debugjsp]: Servlet.service() for servlet debugjsp threw exceptionjavax.servlet.ServletException: Cannot find ActionMappings or ActionFormBeans collection at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:495) at org.apache.jsp.login3_jsp._jspService(login3_jsp.java:80) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:92) at javax.servlet.http.HttpServlet.service(HttpServlet.java:809) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:162) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187) at javax.servlet.http.HttpServlet.service(HttpServlet.java:809) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:200) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:209) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)

Answer 1

public ActionForward execute(ActionMapping actionMapping,
                                 ActionForm actionForm,
                                 HttpServletRequest servletRequest,
                                 HttpServletResponse servletResponse) {
        login3Form login3Form = (login3Form) actionForm;
        throw new java.lang.UnsupportedOperationException(
                "Method $execute() not yet implemented.");
    }
Action为什么这样写？
Action什么事情也没做

Answer 2

找不到org.apache.struts.action.ActionServlet
你的struts包放在工程的WEB-INF/lib下了吗?

Answer 3

你的Action里面execute()方法没有返回一个ActionForward，估计在编辑阶段就应该有错的。然后在配置文件中只有一个<forward name="err" path="/err.jsp" />，也就是说，即使你的程序没有问题，也会跳往错误画面。推荐LZ先把程序调通，没有编译错误在运行比较好！

Answer 4

package login3;import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForm;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.Action;
public class login3Action extends Action {
    public ActionForward execute(ActionMapping actionMapping,
                                 ActionForm actionForm,
                                 HttpServletRequest servletRequest,
                                 HttpServletResponse servletResponse) {
        login3Form login3Form = (login3Form) actionForm;
       /*此处是你用户登陆的验证信息,给出相应的返回页面*/
       return actionMapping.findForward("err");  //返回页面
    }
}