Home/ Questions/Q 3607666
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-18T21:24:16+00:00

While taking lessons in spring3 I coded a sample from a tutorial. I created

  • 0

While taking lessons in spring3 I coded a sample from a tutorial. I created a controller as below

package my.spring.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import my.spring.form.Contact;

@Controller
public class ContactController {
 @RequestMapping(value ="/addContact",method =RequestMethod.POST)
 public String addContact(@ModelAttribute("contact") Contact ct){
  System.out.println("First Name:" + contact.getFirstname() + "Last Name:" + contact.getLastname());
  return "redirect:contacts.htm";  
 }
 @RequestMapping("/contacts")
 public ModelAndView showContacts() {
  System.out.println("showing contacts");  
  return new ModelAndView("contact", "userEntries", new Contact());
 }
}

Then I decided to play around with it and modified the @ModelAttribute in method parameter from

public String addContact(@ModelAttribute("contact") Contact ct)

to

public String addContact(@ModelAttribute("somevalue") Contact ct)

Still I couldn’t find any change in behaviour of the application. This was a bit of surprise for me. As I understood, the data from form is collected in a Contact object and using @ModelAttribute that object is bound to the parameter ct. This parameter is then used to process inside the method.
Is it that the actual string used inside @ModelAttribute( ) doesn’t matter?

Here is the WEB-INF/jsp/contact.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Contact Manager</title>
</head>
<body>
<h2>Contact Manager</h2>
<form:form action="addContact.htm" commandName="userEntries">
<table>
<tr>
 <td>
 <form:label path="firstname">First Name</form:label> 
 </td>
 <td>
 <form:input path="firstname"/>
 </td>
</tr>

<tr>
 <td>
 <form:label path="lastname">Last Name</form:label> 
 </td>
 <td>
 <form:input path="lastname"/>
 </td>
</tr>

<tr>
 <td colspan="2">
 <input type="submit" value="Add Contact"/>
 </td>
</tr>
</table>

</form:form>
</body>
</html>

and the spring servlet configuration 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns:mvc="http://www.springframework.org/schema/mvc"
 xmlns:p="http://www.springframework.org/schema/p"
 xmlns:context="http://www.springframework.org/schema/context"
 xsi:schemaLocation=
 "http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context-3.0.xsd">
 <mvc:annotation-driven/>
 <context:component-scan base-package="my.spring.controller" />
<bean id="viewResolver"
  class="org.springframework.web.servlet.view.UrlBasedViewResolver">
  <property name="viewClass"
   value="org.springframework.web.servlet.view.JstlView" />
  <property name="prefix" value="/WEB-INF/jsp/" />
  <property name="suffix" value=".jsp" />
 </bean>
</beans>

Finally, the index.jsp forwards to contacts

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>my index</title>
</head>
<body>
<jsp:forward page="contacts.htm"></jsp:forward>

</body>
</html>
Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    It will be used for mapping the model attribute to the form:

    <form:form modelAttribute="myObject">

</form>

    You will have to use 

    public String controllerMethod(@ModelAttribute("myObject") Object obj){
    ....
}

    If you don’t use the same value in both model attribute values you won’t be able to see the error messages of the validation (when doing in the controller result.rejectValue and in the jsp <form:errors/> tag).

    There are no differences to populate the values from the form in the object because you can use html tags instead of spring tags, and in the html tags you only have the name attribute to map the value.

    In case you use @ModelAttribute in a method like below, you will insert in the model an attribute named “myObject” with value the object returned. This is another feauture of this annotation and it will be invoked before any method of the controller.

    @ModelAttribute("myObject") Object obj
public Object method(){
    ...
    return obj;
}
    • 0