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

 
sarah Marsh
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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!
 
Jimmy Clark
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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.
 
sarah Marsh
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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">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->

</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"))
 
Cendy Van
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Replace tags form and html by tags html:form and html:text like this :
 
Seetharaman Venkatasamy
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please can you post your LoginForm
 
Raza Khan
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Hi Sarah.. can you give me your email id... i have all in a tutorial that you require.

Thanks,
Khan
 
Seetharaman Venkatasamy
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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
 
Raza Khan
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ya sure... i can mail the tutorial to her...

what is your point Mr. VenkataRaman...
 
Jimmy Clark
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sarah, in the Login.jsp you should have declarations for the Struts HTML JSP tag library and should be using the Struts form tags.
 
sarah Marsh
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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;
}

}
 
sarah Marsh
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Any idea?

Happy Holidays!
 
Jesus Angeles
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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 ]
 
sarah Marsh
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It's a typo in the form.
Thanks a lot, Jesus and everybody!
 
Raza Khan
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