how the value in the form pass into Action class in Struts

Hi, I'm new to Struts.
I created a simple form, it use the text input to send the form data to the server. But in the Action class when I try to get the value from the ActionForm, it has null value(so it throws null pointer exception)?
Where should I check the code?

Thanks!

Struts is a great tool. You first should check the code of the Action class. Copy and paste in a post here so we can see, if you don't mind.

The next place you might look is in the Java Server Page that has the data input form.

Thanks, James. Here's the code.

struts-config.xml:
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE struts-config PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
"http://struts.apache.org/dtds/struts-config_1_3.dtd">

<struts-config>
<form-beans>
<form-bean name="loginForm"
type="cn.itcast.LoginForm"/>
</form-beans>

<action-mappings>

<action path="/login"
type="cn.itcast.LoginAction"
name="loginForm">
<forward name="loginSuccess" path="/LoginSuccess.jsp"/>
<forward name="loginFailure" path="/LoginFailure.jsp"/>
</action>

</action-mappings>
</struts-config>

Web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>

</web-app>

Login.jsp:
<%@ page language="java" pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %>

<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSF 'Login.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">


</head>

<body>
<form action="<%=path%>/login.do" method="post">
username:<input type="text" name="username"><br>
password:<input type="text" name="password"><br>
<input type="submit" value="login">
</form>
</body>
</html>

LoginAction.java:
package cn.itcast;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class LoginAction extends Action {

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

LoginForm loginForm = (LoginForm)form;
if (loginForm.getUsername().equalsIgnoreCase("itcast")){

return mapping.findForward("loginSuccess");
}else{
return mapping.findForward("loginFailure");
}

}

}

Exception at if (loginForm.getUsername().equalsIgnoreCase("itcast"))

Replace tags form and html by tags html:form and html:text like this :

please can you post your LoginForm

Hi Sarah.. can you give me your email id... i have all in a tutorial that you require.

Thanks,
Khan

Originally posted by Raza Khan:
Hi Sarah.. can you give me your email id... i have all in a tutorial that you require.

Cheers. thats the sprit

ya sure... i can mail the tutorial to her...

what is your point Mr. VenkataRaman...

sarah, in the Login.jsp you should have declarations for the Struts HTML JSP tag library and should be using the Struts form tags.

Thanks a lot, everyone! My email july4u2001@yahoo.com

LoginForm.java:

package cn.itcast;

import org.apache.struts.action.ActionForm;

public class LoginForm extends ActionForm {
private String username = null;
private String password = null;
public String getUsername() {
return username;
}
public void setUsernmae(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}

}

Any idea?

Happy Holidays!

Thanks for posting your form class.

Which field is reported null?

If it is the username, the reason is 'mistype':

It should be setUsername, not setUsernmae.
[ December 27, 2008: Message edited by: Jesus Angeles ]

It's a typo in the form.
Thanks a lot, Jesus and everybody!