做表单级验证时报这个错，是什么错急用在线等！！！！！！！！！！

Question

org.apache.jasper.JasperException: org.apache.struts.action.ActionMessage
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1069)
org.apache.struts.action.RequestProcessor.internalModuleRelativeForward(RequestProcessor.java:1012)
org.apache.struts.action.RequestProcessor.processValidate(RequestProcessor.java:980)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:255)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
root cause java.lang.ClassCastException: org.apache.struts.action.ActionMessage
org.apache.struts.taglib.html.ErrorsTag.doStartTag(ErrorsTag.java:215)
org.apache.jsp.inputInfor_jsp._jspx_meth_html_errors_0(inputInfor_jsp.java:205)
org.apache.jsp.inputInfor_jsp._jspx_meth_html_form_0(inputInfor_jsp.java:122)
org.apache.jsp.inputInfor_jsp._jspService(inputInfor_jsp.java:80)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1069)
org.apache.struts.action.RequestProcessor.internalModuleRelativeForward(RequestProcessor.java:1012)
org.apache.struts.action.RequestProcessor.processValidate(RequestProcessor.java:980)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:255)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

Answer 1

关键三点：ActionMessageClassCastExceptionorg.apache.struts.taglib.html.ErrorsTag.doStartTag(ErrorsTag.java:215)==>validate()里面有错误，有个类型不好用，贴代码

Answer 2

这是actionform的代码：
package com.yourcompany.struts.form;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionMapping;
import javax.servlet.http.*;
public class  UserLoginForm extends ActionForm
{
private String userName;
private String password;

public void setUserName(String userName)
{
this.userName = userName;
}
public String getUserName()
{
return userName;
}
public void setPassword(String password)
{
this.password = password;
}
public String getPassword()
{
return password;
}

public ActionErrors validate(ActionMapping mapping,HttpServletRequest request) 
{
ActionErrors errors = new ActionErrors();
//System.out.println("1:No userid.");
//System.out.println("userId=" + userName);
if ( userName == null||userName.trim().equals("") ) 
{
//System.out.println("2:No userid.");
errors.add("userName", new ActionError("errors.userName"));
}
if (( password == null) || password.trim().equals(""))
{
//System.out.println(password.length());
//System.out.println("3:No password.");
errors.add("password", new ActionError("errors.password"));
}
return errors;
}
}

Answer 3

//Created by MyEclipse Struts
// XSL source (default): platform:/plugin/com.genuitec.eclipse.cross.easystruts.eclipse_4.1.1/xslt/JavaClass.xslpackage com.yourcompany.struts.form;import javax.servlet.http.HttpServletRequest;import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionMessage;
public class AddformForm extends ActionForm {
private String SNYZXH;
private String SNYZBM;
private String SNYZMC;
public String getSNYZXH() {
return SNYZXH;
}
public void setSNYZXH(String SNYZXH) {
this.SNYZXH = SNYZXH;
}
public String getSNYZBM() {
return SNYZBM;
}
public void setSNYZBM(String SNYZBM) {
this.SNYZBM = SNYZBM;
}
public String getSNYZMC() {
return SNYZMC;
}
public void setSNYZMC(String SNYZMC) {
this.SNYZMC = SNYZMC;
}
public ActionErrors validate(ActionMapping mapping,HttpServletRequest request) 
{ ActionErrors errors=new ActionErrors();
if(this.SNYZXH==null||this.SNYZXH.trim().equals(""))
{
errors.add("SNYZXH",new ActionMessage("errors.SNYZXH"));

}
if(this.SNYZBM==null||this.SNYZBM.trim().equals(""))
{
errors.add("SNYZBM",new ActionMessage("errors.SNYZBM"));

}
if(this.SNYZMC==null||this.SNYZMC.trim().equals(""))
{
errors.add("SNYZMC",new ActionMessage("errors.SNYZMC"));

}
return errors;
}
}

Answer 4

你看看你错误消息的XML文件里写的和你在FORM里用是不是一样，
关键检查大小写，
这个错误就是说你form里引用的名字在你相应的XML里没有定义，
仔细点找，
例：
errors.add("SNYZXH",new ActionMessage("errors.SNYZXH"));
errors.SNYZXH ，XML文件里没有定义。