Creating our own users with a custom security policy

Spring Security has a highly pluggable architecture, which we shall take full advantage of throughout this chapter.

The key aspects of securing any application are as follows:

• Defining the source of users
• Creating access rules for the users
• Associating various parts of the app with the access rules
• Applying the policy to all aspects of the application

Let’s start with the first step and create a source of users. Spring Security comes with an interface for just this task: UserDetailsService.

To leverage this, we’ll start by creating a SecurityConfig Java class with the following code:

@Configuration
public class SecurityConfig {
  @Bean
  public UserDetailsService userDetailsService() {
    UserDetailsManager userDetailsManager = 
      new InMemoryUserDetailsManager();
    userDetailsManager...