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Fetch User Information on JSP Page

In this topic, we will learn to get information of the logged-in user in the JSP page. Spring provides a tag-lib library that contains several tags including the authentication tag. The authentication tags can be used to get the current user information like his name and role that shows his authority.

To implement this what we need to do is, just add Spring tag-lib dependency to the pom.xml file, declare tag-lib library on top of the JSP page, and use <authentication> tag in the JSP page. So, just follow these steps to implement this in the Spring Security project.

Add Dependency

We need to add this tag-lib dependency to the POM.xml file so that we can able to use the authentication tag.

<dependency>
	<groupId>org.springframework.security</groupId>
	<artifactId>spring-security-taglibs</artifactId>
	<version>5.4.1</version>
</dependency>

Declare library

To use this tag we must declare the library at the top of the JSP page.

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

Add Tag

And finally, use this tag anywhere in the JSP page to show the user information to the browser. For example, we want to get the user name and its authorities then use the following lines in the JSP page.

<security:authentication property="principal.username"/>
<security:authentication property="principal.authorities"/>

Time for an Example

Now, let's understand by example. We created a maven-based Spring Security project that contains the following files.

// AppConfig.java

This is our application configuration file that implements WebMvcConfugurer interface to make this MVC application and created a method viewResolver to map our views files(JSP).

The @EnableWebMvc annotation is used to make our application a web application with an MVC pattern.

The @Configuration annotation is used to declare this class as a configuration class and the @ComponentScan annotation is used to scan the component class of our application.

package com.studytonight;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@EnableWebMvc
@Configuration
@ComponentScan("com.studytonight.controller")
public class AppConfig implements WebMvcConfigurer{
	@Bean
	public ViewResolver viewResolver() {
		InternalResourceViewResolver irvr = new InternalResourceViewResolver();
		irvr.setPrefix("WEB-INF/views/");
		irvr.setSuffix(".jsp");
		irvr.setOrder(0);
		return irvr;
	}
}

// MainApp.java

This class initialize our web application and creates ServletContext by using that we register our AppConfig class(above file).

package com.studytonight;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;
public class MainApp implements WebApplicationInitializer {

	@Override
	public void onStartup(ServletContext servletContext) throws ServletException {
		System.out.println("started");
		AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
		context.register(AppConfig.class);
		context.setServletContext(servletContext);
		ServletRegistration.Dynamic servlet = servletContext.addServlet("dispatcher", new DispatcherServlet(context));
		servlet.setLoadOnStartup(1);
		servlet.addMapping("/");
		context.close();	
	}
}

// SecurityAppInitializer.java

This is the Security initializer class that extends AbstractSecurityWebApplicationInitializer and we passed our SecurityConfig class so that it can read security configurations.

package com.studytonight;

import org.springframework.security.web.context.AbstractSecurityWebApplicationInitializer;
public class SecurityAppInitializer  extends AbstractSecurityWebApplicationInitializer {

	public SecurityAppInitializer() {
		super(SecurityConfig.class);
	}
}

// SecurityConfig.java

This is our security configuration file that extends WebSecurityConfigurerAdapter class and provides several methods such as configure() to configure the security. Spring Security provides AuthenticationManagerBuilder class that works as an Authentication Manager and provides several methods to authenticate the user. Here, we are using inMemoryAuthentication concept that allows mapping hard-coded user values.

We used HttpSecurity class to configure the login page. The loginPage() method is used to specify our login.jsp page. We can also use any other name for the login form such as login-form.jsp or user-login.jsp and then specify the mapping to this method. The "/login" value passed here will map to the controller's action and then render the JSP page.

package com.studytonight;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.User.UserBuilder;

@Configuration
@EnableWebSecurity	
public class SecurityConfig extends WebSecurityConfigurerAdapter{

	@Override
	protected void configure(AuthenticationManagerBuilder auth) throws Exception {

		UserBuilder users = User.withDefaultPasswordEncoder();		
		auth.inMemoryAuthentication()
		.withUser(users.username("studytonight").password("abc123").roles("admin"));
	}

	@Autowired
	protected void configure(HttpSecurity hs) throws Exception {
		hs.authorizeRequests().anyRequest()
		.authenticated()
		.and()
		.formLogin()
		.loginPage("/login")
		.loginProcessingUrl("/authenticateTheUser")
		.permitAll()
		.and()
		.logout()
		.permitAll();
	}
}

// UserController.java

This is our controller class that works as a user request handler and maps user requests with the resources and returns responses accordingly. We created the login() method to render the login page and the home() method to show the index.jsp page and course() method to display course.jsp page.

package com.studytonight.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class UserController {

	@GetMapping("/login")
	public String login() {
		return "login";
	}
	
	@GetMapping("/")  
	public String home() {
		return "index";
	}

	@GetMapping("/java-course")
	public String course() {
		return "course";
	}

	@GetMapping("/premium-courses")
	public String premiumCourse() {
		return "premium-courses";
	}
}

View Files

These are views files of our project that displayed to the browser. See the code.

// course.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Course Page</title>
</head>
<body>
	<h2>List of Courses</h2>
	<ul>
		<li>Java</li>
		<li>Python</li>
		<li>C++</li>
		<li>Linux</li>
	</ul>
</body>
</html>

// index.jsp

Here, we used the authentication tag to show the username and authorities of the logged-in user.

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
	<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
	<%@ taglib prefix="security" uri="http://www.springframework.org/security/tags"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Home Page</title>
</head>
<body>
	<h2>Welcome to Studytonight!</h2>
	<h3>
		<a href="java-course">Study Java</a>
	</h3>
	<h2>
		<a href="premium-courses">Study Premium Courses</a>
	</h2>
	<br><br>
	User: <security:authentication property="principal.username"/> <br><br>
	Role: <security:authentication property="principal.authorities"/>
	<br><br>
	<form:form
		action="${pageContext.request.contextPath}/logout"
		method="post">
		<input type="submit" value="logout">
	</form:form>
</body>
</html>

// login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Login Page</title>
</head>
<body>
	<form:form
		action="${pageContext.request.contextPath}/authenticateTheUser"
		method="post">
		<c:if test="${param.error!=null}">
			<p style="color: red">You entered wrong credentials!</p>

		</c:if>
		<c:if test="${param.logout!=null}">
			<p style="color: green">You have successfully logged out.!</p>
		</c:if>
		<label for="name">Enter User Name</label>
		<input type="text" name="username">
		<br>
		<br>
		<label for="password">Enter Password</label>
		<input type="password" name="password">
		<br>
		<br>
		<input type="submit" value="Login">
	</form:form>
</body>
</html>

// premium-courses.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Course Page</title>
</head>
<body>
	<h2>List of Premium Courses</h2>
	<ul>
		<li>Spring Framework</li>
		<li>Pandas</li>
		<li>Spring Security</li>
	</ul>
</body>
</html>

// pom.xml

This file contains all the dependencies of this project such as spring jars, servlet jars, etc. Put these dependencies into your project to run the application.

<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.studytonight</groupId>
	<artifactId>springwithsecurity</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<properties>
		<spring.version>5.2.8.RELEASE</spring.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-core</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/javax.servlet/servlet-api -->
		<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>4.0.1</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/jstl/jstl -->
		<dependency>
			<groupId>jstl</groupId>
			<artifactId>jstl</artifactId>
			<version>1.2</version>
		</dependency>



		<!-- https://mvnrepository.com/artifact/javax.servlet.jsp/javax.servlet.jsp-api -->
		<dependency>
			<groupId>javax.servlet.jsp</groupId>
			<artifactId>javax.servlet.jsp-api</artifactId>
			<version>2.3.3</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/javax.servlet.jsp.jstl/jstl-api -->
		<dependency>
			<groupId>javax.servlet.jsp.jstl</groupId>
			<artifactId>jstl-api</artifactId>
			<version>1.2</version>
		</dependency>

		<!-- https://mvnrepository.com/artifact/javax.xml.bind/jaxb-api -->
		<dependency>
			<groupId>javax.xml.bind</groupId>
			<artifactId>jaxb-api</artifactId>
			<version>2.3.0</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-web -->
		<dependency>
			<groupId>org.springframework.security</groupId>
			<artifactId>spring-security-web</artifactId>
			<version>5.4.2</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-config -->
		<dependency>
			<groupId>org.springframework.security</groupId>
			<artifactId>spring-security-config</artifactId>
			<version>5.4.2</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-taglibs -->
		<dependency>
			<groupId>org.springframework.security</groupId>
			<artifactId>spring-security-taglibs</artifactId>
			<version>5.4.1</version>
		</dependency>
	</dependencies>
	<build>
		<plugins>
			<plugin>
				<artifactId>maven-war-plugin</artifactId>
				<version>3.2.3</version>
				<configuration>
					<warSourceDirectory>WebContent</warSourceDirectory>
				</configuration>
			</plugin>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.5.1</version>
				<configuration>
					<source>11</source>
					<target>11</target>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

Project Structure

After creating these files our project will look like the below. You can refer to this to understand the directory structure of the project.

Run the Application

After successfully completing the project and adding the dependencies run the application and you will get the output as below.

This is our own login page that will be submitted to /authenticeTheUser URL and match the username and password with the credentials provided in the SecurityConfig.java file.

Provide Correct Username and Password

Home page

Now, you are successfully logged in to the application. This is our index.jsp file renders as a home page to the browser.

Notice, Since we used authenticate tag so it shows the user details such as username and user role.