Spring Security – UserDetailsService and UserDetails with Example

Spring Security is a framework that allows a programmer to use JEE components to set security limitations on Spring-framework-based Web applications. In a nutshell, it’s a library that can be utilized and customized to suit the demands of the programmer. Read more on Spring Security and its Features in this article Introduction to Spring Security and its Features. UserDetails and UserDetailsService are two major concepts to learn in Spring Security. So we will learn these two concepts with proper examples.

UserDetailsService and UserDetails

In Spring Security, the UserDetailsService interface is a core component used for loading user-specific data. It is responsible for retrieving user information from a backend data source, such as a database or an external service, and returning an instance of the UserDetails interface.

The UserDetailsService interface has a single method called loadUserByUsername(), which takes a username as a parameter and returns a fully populated UserDetails object. The UserDetails object represents the authenticated user in the Spring Security framework and contains details such as the user’s username, password, authorities (roles), and additional attributes.

In this article, we are going to use

• InMemoryUserDetailsManager class, which is an implementation of the UserDetailsService interface that stores user details in memory. It is commonly used for testing and development purposes when you want to define user accounts directly in your code without the need for a persistent data store, and
• User class, which is a convenient builder class provided by the framework for creating instances of UserDetails. It is used to represent user account details, such as the username, password, and authorities (roles) associated with a user. The User class provides a fluent API for constructing UserDetails objects with various attributes. It offers methods to set the username, password, and roles for a user, among other properties.

So we are going to create the user with the help of both InMemoryUserDetailsManager and User class. A sample code is given below

@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        
        InMemoryUserDetailsManager userDetailsManager = new InMemoryUserDetailsManager();
        
        // Method 1 - Creating username, password, and role
        ArrayList<GrantedAuthority> roles = new ArrayList<GrantedAuthority>();
        
        SimpleGrantedAuthority role1 = new SimpleGrantedAuthority("USER");
        SimpleGrantedAuthority role2 = new SimpleGrantedAuthority("ADMIN");
        
        roles.add(role1);
        roles.add(role2);
        
        User anshulUser = new User("anshul", "123", roles);
        
        // Method 2 - Creating username, password, and role
        // UserDetails anshulUser = User.withUsername("Anshul").password("123").roles("USER", "ADMIN").build();
        
        userDetailsManager.createUser(anshulUser);
        auth.userDetailsService(userDetailsManager);
         
}

Example Project

We’re going to build on top of the simple Spring MVC example.

Step 1: Create Your Project and Configure Apache Tomcat Server

Note: We are going to use Spring Tool Suite 4 IDE for this project. Please refer to this article to install STS in your local machine How to Download and Install Spring Tool Suite (Spring Tools 4 for Eclipse) IDE.

• Create a Dynamic Web Project in your STS IDE. You may refer to this article to create a Dynamic Web Project in STS: How to Create a Dynamic Web Project in Spring Tool Suite?
• Configure Apache Tomcat Server and configure the Tomcat Server with the application. Now we are ready to go.

Step 2: Folder Structure

Before moving to the project let’s have a look at the complete project structure for our Spring MVC application.

Step 3: Add Dependencies to pom.xml File

Add the following dependencies to your pom.xml file

• Spring Web MVC
• Java Servlet API
• Spring Security Config
• Spring Security Web

XML

<dependencies>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.24</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-config -->
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-config</artifactId>
        <version>5.7.3</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-web -->
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-web</artifactId>
        <version>5.7.3</version>
    </dependency>

</dependencies>

Below is the complete pom.xml file. Please cross-verify if you have missed some dependencies.

XML

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

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.gfg.springsecurity</groupId>
  <artifactId>springsecurity</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>springsecurity Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.gfg.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.24</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-config -->
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-config</artifactId>
        <version>5.7.3</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-web -->
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-web</artifactId>
        <version>5.7.3</version>
    </dependency>

  </dependencies>

  <build>
    <finalName>springsecurity</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

Step 4: Configuring Dispatcher Servlet

Please refer to this article What is Dispatcher Servlet in Spring? and read more about Dispatcher Servlet which is a very very important concept to understand. Now we are going to configure Dispatcher Servlet with our Spring MVC application. Go to the src > main > java and create a class WebAppInitilizer. Below is the code for the WebAppInitilizer.java file.

File: WebAppInitilizer.java

Java

package com.gfg.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class WebAppInitilizer extends
               AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        Class[] configFiles = {MyAppConfig.class};
        return configFiles;
    }

    @Override
    protected String[] getServletMappings() {
        String[] mappings = {"/"};
        return mappings;
    }

}

Create another class in the same location (src > main > java) and name it MyAppConfig. Below is the code for the MyAppConfig.java file.

File: MyAppConfig.java

Java

package com.gfg.config;

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

@Configuration
@EnableWebMvc
@ComponentScan("com")
public class MyAppConfig {

}

Reference article: Spring – Configure Dispatcher Servlet in Three Different Ways

Step 5: Create Your Spring MVC Controller

Go to the src > main > java and create a class GfgController. Below is the code for the GfgController.java file.

File: GfgController.java

Java

package com.gfg.controller;

import java.security.Principal;
import java.util.Collection;

import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class GfgController {

    // Principal means username
    @GetMapping("/")
    public String helloGfg(Principal principal, Authentication auth, Model model) {
        // Get the Username
        String userName = principal.getName();
        System.out.println("Current Logged in User is: " + userName);

        // Get the User Roles/Authorities
        Collection<? extends GrantedAuthority> authorities = auth.getAuthorities();
        System.out.println("Current Logged in User Roles are: " + authorities);

        model.addAttribute("username", userName);
        model.addAttribute("roles", authorities);

        return "hello-gfg";
    }

}

Go to the src > main > java and create a class LoginController. Below is the code for the LoginController.java file.

File: LoginController.java

Java

package com.gfg.controller;

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

@Controller
public class LoginController {

    @GetMapping("/customLogin")
    public String customLogin() {
        return "custom-login";
    }

}

Reference article: Create and Run Your First Spring MVC Controller in Eclipse/Spring Tool Suite

Step 6: Create Your Spring MVC Views

Go to the src > main > webapp > WEB-INF > right-click > New > Folder and name the folder as views. Then views > right-click > New > JSP File and name your first view. Here we have named it as hello-gfg.jsp file. Below is the code for the hello-gfg.jsp file. We have created a simple web page inside that file.

File: hello-gfg.jsp

HTML

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" isELIgnored = "false" %>
<!DOCTYPE html>
<html>
<body bgcolor="green">

    <h1>Hi ${username} !!</h1>

    <form:form action="logout" method="POST">

        <input type="submit" value="Logout">

    </form:form>


</body>
</html>

Also, create another view named custom-login.jsp file. Below is the code for the custom-login.jsp file. We have created a simple login form inside that file.

File: custom-login.jsp

HTML

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<!DOCTYPE html>
<html>
<title>GFG Login Page</title>
<body bgcolor="green">
    <h1>Custom Login Page</h1>

    <form:form action="process-login" method="POST">

        Username : <input type="text" name="username">
        <br/>
        Password : <input type="password" name="password">
        <br/>
        <input type="submit" value="Login">

    </form:form>

</body>
</html>

Reference article:

• How to Create Your First View in Spring MVC?
• Spring – MVC Form Tag Library

Step 7: Setting Up ViewResolver in Spring MVC

Go to the src > main > java > MyAppConfig and set your ViewResolver like this

File: MyAppConfig.java

Java

package com.gfg.config;

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

@Configuration
@EnableWebMvc
@ComponentScan("com")
public class MyAppConfig {

    @Bean
    InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/views/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }

}

Reference article: ViewResolver in Spring MVC

Step 8: Setting Up Spring Security Filter Chain

Go to the src > main > java and create a class MySecurityAppConfig and annotate the class with @EnableWebSecurity annotation. This class will help to create the spring security filter chain. Below is the code for the MySecurityAppConfig.java file.

File: MySecurityAppConfig.java

Java

package com.gfg.config;

import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;

// This class will help to create
// spring security filter chain
@EnableWebSecurity
public class MySecurityAppConfig extends WebSecurityConfigurerAdapter {

}

Step 9: Create Spring Security Initilizer

Go to the src > main > java and create a class SecurityInitializer. This class will help to register the spring security filter chain with our application. Below is the code for the SecurityInitializer.java file.

File: SecurityInitializer.java

Java

package com.gfg.config;

import org.springframework.security.web.context.AbstractSecurityWebApplicationInitializer;

// This class will help to register spring security
// filter chain with our application
public class SecurityInitializer extends AbstractSecurityWebApplicationInitializer {

}

Now we are done with setting up our Spring Security Filter Chain.

Step 10: Create Users and Password Encoder

Modify the MyAppConfig file. Here we are going to create the PasswordEncoder Bean.

File: MyAppConfig.java

Java

package com.gfg.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc
@ComponentScan("com")
public class MyAppConfig {

    @Bean
    InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/views/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }

      // Create the bean for PasswordEncoder
    @Bean
    PasswordEncoder getPasswordEncoder() {
        return NoOpPasswordEncoder.getInstance();
    }

}

Modify the MySecurityAppConfig file. Here we are going to create the User, and we are going to provide the password. And we are also going to provide the roles to the user. But this time use the InMemoryUserDetailsManager and User class.

File: MySecurityAppConfig.java

Java

package com.gfg.config;

import java.util.ArrayList;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
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.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.provisioning.InMemoryUserDetailsManager;

// This class will help to create
@SuppressWarnings("deprecation")
// spring security filter chain
@EnableWebSecurity
public class MySecurityAppConfig extends WebSecurityConfigurerAdapter {

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

        InMemoryUserDetailsManager userDetailsManager = new InMemoryUserDetailsManager();

        // Method 1 - Creating username, password, and role
        ArrayList<GrantedAuthority> roles = new ArrayList<GrantedAuthority>();

        SimpleGrantedAuthority role1 = new SimpleGrantedAuthority("USER");
        SimpleGrantedAuthority role2 = new SimpleGrantedAuthority("ADMIN");

        roles.add(role1);
        roles.add(role2);

        User anshulUser = new User("anshul", "123", roles);

        // Method 2 - Creating username, password, and role
        // UserDetails anshulUser = User.withUsername("Anshul").password("123").roles("USER", "ADMIN").build();

        userDetailsManager.createUser(anshulUser);
        auth.userDetailsService(userDetailsManager);

    }

    // Configuring Form Login through configure method
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
        .authorizeHttpRequests()
        .anyRequest()
        .authenticated()
        .and()
        .formLogin().loginPage("/customLogin").loginProcessingUrl("/process-login").permitAll()
        .and()
        .httpBasic()
        .and().logout().permitAll();
    }

}

Now, let’s run the application and test it out.

Step 11: Run Your Spring MVC Application

To run our Spring MVC Application right-click on your project > Run As > Run on Server. After that use the following URL to run your controller.

http://localhost:8080/springsecurity/customLogin

And it will ask for authentication to use the endpoint and a pop-up screen will be shown like this.

Now sign in with your database credentials

• Username: anshul
• Password: 123

And now you can access your homepage and you can see we get the Current Logged in User Name and display it in a view.