Spring Security – Filter Chain 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. Because it is a part of the same Spring family as Spring Web MVC, it works well together. The most significant benefit of this framework is that it is both strong and very adaptable. Although it adheres to Spring’s set-up conventions, programmers may select between default provisions and modify them to their specific requirements. Read more on Spring Security and its Features in this article Introduction to Spring Security and its Features.

What is Filter Chain in Spring Security?

Spring Security utilizes the filter chain to perform most of the security features. Internally Spring Security maintains a filter chain where each filter has a specific responsibility. The filters are added or removed from the configuration relying on which services are needed. The ordering of the filters is crucial as there are dependencies between them. This is how the filter chain work in a web application:

In the above image, the client sends the request for a resource and the application container creates a filter chain to execute the incoming request. Each HttpServletRequest passes through the filter chain based on the path of the request URI. Let’s understand the whole concept by developing a Spring MVC application.

Example Project

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.

Folder Structure

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

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

@Controller
public class GfgController {

    @GetMapping("/gfg")
    public String helloGfg() {
        return "hello-gfg";
    }

}

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

Step 6: Create Your Spring MVC View

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

<!DOCTYPE html>
<html>
<body bgcolor="green">
    <h1>Hello GeeksforGeeks!</h1>
</body>
</html>

Reference article: How to Create Your First View in Spring MVC?

Step 7: Setting Up ViewResolver in Spring MVC

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

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

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 {

}

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. Let’s run the application and test it out.

Step 10: 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/hello-gfg

The time when you hot the URL you can see it will redirect automatically to this URL

http://localhost:8080/springsecurity/login

And the output is something like this.

So you have successfully created your Filter Chain with the help of Spring Security.