Spring MVC Login example

Spring 2.5 MVC User Login Example

This section explains you how you can make Login example using Spring MVC module. In this login example we are not connecting to any database, but you can easily add the database access code to validate your user. In this example if user enters Username: admin and Password: admin, user get validates successfully and success page is displayed. If user enters something else error message is displayed. We have also validated the form data using the a custom validator class.

Here we will create a user login web application that accept two values username and password entered by the User. If the username and password is correct then user successfully login otherwise application display errors for user.

This video tutorial is made using the Spring Framework 2.5 and you will learn to make form in Spring MVC. Following is the links of the similar tutorial develop using the latest version of Spring MVC:

Above are the latest tutorials of Spring MVC Login form.

Following video instruction teaches you how to download and run the code of this example from Eclipse IDE. Eclipse IDE and Tomcat server is required to run this program.

Video Tutorial: How to create Spring MVC Login Form?

Step 1:

Now we will create a index.jsp in project's WebContent folder. In the index.jsp file we will create a hyperlink "User Login Here" that will be linked "login.html" file. The code of the index.jsp is:

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<html>

<head>

<title>Login Link Page</title>

</head>

<a href="login.html">User Login Here</a><br/><br/>

</center>

</body>

</html>

Step 2:

Now we will configured the web.xml file for the DispatcherServlet. The code for web.xml is:

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns="http://java.sun.com/xml/ns/j2ee"

xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_5.xsd"

version="2.5">

<servlet-name>dispatcher</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>dispatcher</servlet-name>

<url-pattern>*.html</url-pattern>

</servlet-mapping>

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

<taglib-uri>/spring</taglib-uri>

<taglib-location>/WEB-INF/spring.tld</taglib-location>

</taglib>

</web-app>

Step 3:

Now we will create dispatcher-servlet.xml inside the WEB-INF folder that will have all the configuration beans for handle the user requests. The code of the dispatcher-servlet.xml is:

<?xml version="1.0" encoding="UTF-8"?>

<beans

xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"

xmlns:p="http://www.springframework.org/schema/p">

<bean id="viewResolver"

class="org.springframework.web.servlet.view.InternalResourceViewResolver">

</property>

</property>

</bean>

<bean id="urlMapping"

class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">

<list>

</list>

</property>

<map>

</entry>

</map>

</property>

</bean>

<property name="sessionForm"><value>false</value></property>

<property name="commandName"><value>login</value></property>

<property name="commandClass"><value>net.roseindia.web.Login</value></property>

<property name="formView"><value>login</value></property>

<property name="successView"><value>success</value></property>

</bean>

</bean>

</beans>

Step 4:

Now we will create two jsp files inside WEB-INF/jsp/ folder. First is login.jsp for taking input from the user and other is success.jsp for display the login success in this application. The login.jsp file will have two text fields (username and password) for take input by the users.

The code of the login.jsp is:

<%@ taglib prefix="core" uri="http://java.sun.com/jsp/jstl/core" %>

<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>

<%@ taglib prefix="spring" uri="/spring"%>

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>

<html>

<head><title>Login</title></head>

<body>

<h3>Login page</h3>

<br/>

<form:form commandName="login" method="POST" name="login">

Username:<form:input path="username"/>
<font color="red"><form:errors path="username"/></font><br/><br/>

Password:<form:password path="password"/>
<font color="red"><form:errors path="password"/></font><br/><br/>

</form:form>

</center>

</body>

</html>

Step 5:

The success.jsp file is contain code for display login success and contain the reverse link for users to come back on the login.html page. The code of the success.jsp is:

<%@ page session="false"%>

<%@ taglib prefix="core" uri="http://java.sun.com/jsp/jstl/core" %>

<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>

<%@ taglib prefix="spring" uri="/spring" %>

<html>

<head>

<title>Success</title>

</head>

<body>

<h1>Welcome <core:out value="${name}"/></h1><br>

</center>

</body>

</html>

Step 6:

Now we will create a Login.java file inside the src folder that will have the business logic for the user login application. In this file we will declared two private variable username and password and create setter and getter method for username and password. The code of the Login.java is:


							package net.roseindia.web;

							

							public class Login {

							  public Login(){}

							  private String username;

							  private String password;

							

							  public String getPassword() {

							  return password;

							  }

							

							  public void setPassword(String password) {

							  this.password = password;

							  }

							

							  public String getUsername() {

							  return username;

							  }

							

							  public void setUsername(String username) {

							  this.username = username;

							

							  }

							}

We have configure this class in dispatcher-servlet..xml through commandName and commandClass. The code for the configuration in the dispatcher-servlet.xml is:

<bean id="loginController" class="net.roseindia.web.LoginFormController">

<property name="commandName"><value>login</value></property>

<property name="commandClass"><value>net.roseindia.web.Login</value></property>

</bean>

Step 7:

Now we will create a LoginFormController.java file that extends SimpleFormController for control the login request and return ModelAndView. we have configure this controller in dispatcher-servlet.xml by adding following properties:

<property name="urlMap">

<map>

<entry key="/login.html">

<ref bean="loginController"/>

</entry>

</map>

</property>

This code is include in the urlMap for mapping controller for a particular request and define controller by using bean properties adding following code:

<bean id="loginController" class="net.roseindia.web.LoginFormController">

</bean>

The LoginFormController.java code is:


						package net.roseindia.web;

						

						import javax.servlet.http.HttpServletRequest;

						import javax.servlet.ServletException;

						import org.springframework.web.servlet.ModelAndView;

						import org.springframework.web.servlet.view.RedirectView;

						import org.springframework.web.servlet.mvc.SimpleFormController;

						

						import net.roseindia.web.Login;

						

						@SuppressWarnings("deprecation")

						public class LoginFormController extends SimpleFormController {

						  

						  @Override

						  protected ModelAndView onSubmit(Object command) throws ServletException {

						  Login login = (Login) command;

						  String name = login.getUsername();

						  String prestatement = "Hello";

						  

						  ModelAndView modelAndView = new ModelAndView(getSuccessView());

						  modelAndView.addObject("name", name);  

						  return modelAndView;

						  

						  }

						}

Step 8:

Now we will create a LoginValidator.java file in the project src directory for validate the login form. DispatcherServlet gives a property to add validator for a login request. The Code for dispatcher-servlet servlet.xml is:

<bean id="loginValidator" class="net.roseindia.web.LoginValidator"/>

<bean id="loginController" class="net.roseindia.web.LoginFormController">

<property name="validator"><ref bean="loginValidator"/></property>

</bean>

The LoginValidator.java file code is:


							package net.roseindia.web;

							import org.springframework.validation.Errors;

							import org.springframework.validation.Validator;

							import org.springframework.validation.ValidationUtils;

							

							import net.roseindia.web.*;

							

							public class LoginValidator implements Validator {

							

							 @Override

							  public boolean supports(Class clazz) {

							  return Login.class.isAssignableFrom(clazz);

							  }

							  public void validate(Object obj, Errors errors) {

							  Login login = (Login) obj;  

							  if (login.getUsername() == null || login.getUsername().length() == 0) {

							  errors.rejectValue("username", 

						"error.empty.field", "Please Enter User Name");

							  }

							  else if (!login.getUsername().equals("admin")) {

							  errors.rejectValue("username", "unknown.user", "Unknown User");

							  }

							  if (login.getPassword() == null || login.getPassword().length() == 0) {

							  errors.rejectValue("password", 

						"error.empty.field", "Please Enter Password");

							  } 

							  else if (!login.getPassword().equals("admin")) {

							  errors.rejectValue("password", "wrong.password", "Wrong Password");

							  }  

							  }

							}

Now we will run this login application and see the out put like:

Now click on this hyperlink the application display user login form like:

Now input "admin" as username and "admin" as password and test it. The result is:

Download Code of Spring MVC Login Example discussed here.

Spring MVC Login Example