5. Java Configuration

General support for Java Configuration was added to Spring Framework in Spring 3.1. Since Spring Security 3.2 there has been Spring Security Java Configuration support which enables users to easily configure Spring Security without the use of any XML.

If you are familiar with the Chapter 6, Security Namespace Configuration then you should find quite a few similarities between it and the Security Java Configuration support.

[Note]Note

Spring Security provides lots of sample applications which demonstrate the use of Spring Security Java Configuration.

5.1 Hello Web Security Java Configuration

The first step is to create our Spring Security Java Configuration. The configuration creates a Servlet Filter known as the springSecurityFilterChain which is responsible for all the security (protecting the application URLs, validating submitted username and passwords, redirecting to the log in form, etc) within your application. You can find the most basic example of a Spring Security Java Configuration below:

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.annotation.*;
import org.springframework.security.config.annotation.authentication.builders.*;
import org.springframework.security.config.annotation.web.configuration.*;

@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

	@Bean
	public UserDetailsService userDetailsService() throws Exception {
		InMemoryUserDetailsManager manager = new InMemoryUserDetailsManager();
		manager.createUser(User.withUsername("user").password("password").roles("USER").build());
		return manager;
	}
}

There really isn’t much to this configuration, but it does a lot. You can find a summary of the features below:

5.1.1 AbstractSecurityWebApplicationInitializer

The next step is to register the springSecurityFilterChain with the war. This can be done in Java Configuration with Spring’s WebApplicationInitializer support in a Servlet 3.0+ environment. Not suprisingly, Spring Security provides a base class AbstractSecurityWebApplicationInitializer that will ensure the springSecurityFilterChain gets registered for you. The way in which we use AbstractSecurityWebApplicationInitializer differs depending on if we are already using Spring or if Spring Security is the only Spring component in our application.

5.1.2 AbstractSecurityWebApplicationInitializer without Existing Spring

If you are not using Spring or Spring MVC, you will need to pass in the WebSecurityConfig into the superclass to ensure the configuration is picked up. You can find an example below:

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

public class SecurityWebApplicationInitializer
	extends AbstractSecurityWebApplicationInitializer {

	public SecurityWebApplicationInitializer() {
		super(WebSecurityConfig.class);
	}
}

The SecurityWebApplicationInitializer will do the following things:

  • Automatically register the springSecurityFilterChain Filter for every URL in your application
  • Add a ContextLoaderListener that loads the WebSecurityConfig.

5.1.3 AbstractSecurityWebApplicationInitializer with Spring MVC

If we were using Spring elsewhere in our application we probably already had a WebApplicationInitializer that is loading our Spring Configuration. If we use the previous configuration we would get an error. Instead, we should register Spring Security with the existing ApplicationContext. For example, if we were using Spring MVC our SecurityWebApplicationInitializer would look something like the following:

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

public class SecurityWebApplicationInitializer
	extends AbstractSecurityWebApplicationInitializer {

}

This would simply only register the springSecurityFilterChain Filter for every URL in your application. After that we would ensure that WebSecurityConfig was loaded in our existing ApplicationInitializer. For example, if we were using Spring MVC it would be added in the getRootConfigClasses()

public class MvcWebApplicationInitializer extends
		AbstractAnnotationConfigDispatcherServletInitializer {

	@Override
	protected Class<?>[] getRootConfigClasses() {
		return new Class[] { WebSecurityConfig.class };
	}

	// ... other overrides ...
}

5.2 HttpSecurity

Thus far our WebSecurityConfig only contains information about how to authenticate our users. How does Spring Security know that we want to require all users to be authenticated? How does Spring Security know we want to support form based authentication? The reason for this is that the WebSecurityConfigurerAdapter provides a default configuration in the configure(HttpSecurity http) method that looks like:

protected void configure(HttpSecurity http) throws Exception {
	http
		.authorizeRequests()
			.anyRequest().authenticated()
			.and()
		.formLogin()
			.and()
		.httpBasic();
}

The default configuration above:

  • Ensures that any request to our application requires the user to be authenticated
  • Allows users to authenticate with form based login
  • Allows users to authenticate with HTTP Basic authentication

You will notice that this configuration is quite similar the XML Namespace configuration:

<http>
	<intercept-url pattern="/**" access="authenticated"/>
	<form-login />
	<http-basic />
</http>

The Java Configuration equivalent of closing an XML tag is expressed using the and() method which allows us to continue configuring the parent. If you read the code it also makes sense. I want to configure authorized requests and configure form login and configure HTTP Basic authentication.

However, Java Configuration has different defaults URLs and parameters. Keep this in mind when creating custom login pages. The result is that our URLs are more RESTful. Additionally, it is not quite so obvious we are using Spring Security which helps to prevent information leaks. For example:

5.3 Java Configuration and Form Login

You might be wondering where the login form came from when you were prompted to log in, since we made no mention of any HTML files or JSPs. Since Spring Security’s default configuration does not explicitly set a URL for the login page, Spring Security generates one automatically, based on the features that are enabled and using standard values for the URL which processes the submitted login, the default target URL the user will be sent to after logging in and so on.

While the automatically generated log in page is convenient to get up and running quickly, most applications will want to provide their own log in page. To do so we can update our configuration as seen below:

protected void configure(HttpSecurity http) throws Exception {
	http
		.authorizeRequests()
			.anyRequest().authenticated()
			.and()
		.formLogin()
			.loginPage("/login") 1
			.permitAll();        2
}

1

The updated configuration specifies the location of the log in page.

2

We must grant all users (i.e. unauthenticated users) access to our log in page. The formLogin().permitAll() method allows granting access to all users for all URLs associated with form based log in.

An example log in page implemented with JSPs for our current configuration can be seen below:

[Note]Note

The login page below represents our current configuration. We could easily update our configuration if some of the defaults do not meet our needs.

<c:url value="/login" var="loginUrl"/>
<form action="${loginUrl}" method="post">       1
	<c:if test="${param.error != null}">        2
		<p>
			Invalid username and password.
		</p>
	</c:if>
	<c:if test="${param.logout != null}">       3
		<p>
			You have been logged out.
		</p>
	</c:if>
	<p>
		<label for="username">Username</label>
		<input type="text" id="username" name="username"/>	4
	</p>
	<p>
		<label for="password">Password</label>
		<input type="password" id="password" name="password"/>	5
	</p>
	<input type="hidden"                        6
		name="${_csrf.parameterName}"
		value="${_csrf.token}"/>
	<button type="submit" class="btn">Log in</button>
</form>

1

A POST to the /login URL will attempt to authenticate the user

2

If the query parameter error exists, authentication was attempted and failed

3

If the query parameter logout exists, the user was successfully logged out

4

The username must be present as the HTTP parameter named username

5

The password must be present as the HTTP parameter named password

6

We must Section 18.4.3, “Include the CSRF Token” To learn more read the Chapter 18, Cross Site Request Forgery (CSRF) section of the reference

5.4 Authorize Requests

Our examples have only required users to be authenticated and have done so for every URL in our application. We can specify custom requirements for our URLs by adding multiple children to our http.authorizeRequests() method. For example:

protected void configure(HttpSecurity http) throws Exception {
	http
		.authorizeRequests()                                                                1
			.antMatchers("/resources/**", "/signup", "/about").permitAll()                  2
			.antMatchers("/admin/**").hasRole("ADMIN")                                      3
			.antMatchers("/db/**").access("hasRole('ADMIN') and hasRole('DBA')")            4
			.anyRequest().authenticated()                                                   5
			.and()
		// ...
		.formLogin();
}

1

There are multiple children to the http.authorizeRequests() method each matcher is considered in the order they were declared.

2

We specified multiple URL patterns that any user can access. Specifically, any user can access a request if the URL starts with "/resources/", equals "/signup", or equals "/about".

3

Any URL that starts with "/admin/" will be restricted to users who have the role "ROLE_ADMIN". You will notice that since we are invoking the hasRole method we do not need to specify the "ROLE_" prefix.

4

Any URL that starts with "/db/" requires the user to have both "ROLE_ADMIN" and "ROLE_DBA". You will notice that since we are using the hasRole expression we do not need to specify the "ROLE_" prefix.

5

Any URL that has not already been matched on only requires that the user be authenticated

5.5 Handling Logouts

When using the WebSecurityConfigurerAdapter, logout capabilities are automatically applied. The default is that accessing the URL /logout will log the user out by:

  • Invalidating the HTTP Session
  • Cleaning up any RememberMe authentication that was configured
  • Clearing the SecurityContextHolder
  • Redirect to /login?logout

Similar to configuring login capabilities, however, you also have various options to further customize your logout requirements:

protected void configure(HttpSecurity http) throws Exception {
	http
		.logout()                                                                1
			.logoutUrl("/my/logout")                                                 2
			.logoutSuccessUrl("/my/index")                                           3
			.logoutSuccessHandler(logoutSuccessHandler)                              4
			.invalidateHttpSession(true)                                             5
			.addLogoutHandler(logoutHandler)                                         6
			.deleteCookies(cookieNamesToClear)                                       7
			.and()
		...
}

1

Provides logout support. This is automatically applied when using WebSecurityConfigurerAdapter.

2

The URL that triggers log out to occur (default is /logout). If CSRF protection is enabled (default), then the request must also be a POST. For more information, please consult the JavaDoc.

3

The URL to redirect to after logout has occurred. The default is /login?logout. For more information, please consult the JavaDoc.

4

Let’s you specify a custom LogoutSuccessHandler. If this is specified, logoutSuccessUrl() is ignored. For more information, please consult the JavaDoc.

5

Specify whether to invalidate the HttpSession at the time of logout. This is true by default. Configures the SecurityContextLogoutHandler under the covers. For more information, please consult the JavaDoc.

6

Adds a LogoutHandler. SecurityContextLogoutHandler is added as the last LogoutHandler by default.

7

Allows specifying the names of cookies to be removed on logout success. This is a shortcut for adding a CookieClearingLogoutHandler explicitly.

[Note]Note

Logouts can of course also be configured using the XML Namespace notation. Please see the documentation for the logout element in the Spring Security XML Namespace section for further details.

Generally, in order to customize logout functionality, you can add LogoutHandler and/or LogoutSuccessHandler implementations. For many common scenarios, these handlers are applied under the covers when using the fluent API.

5.5.1 LogoutHandler

Generally, LogoutHandler implementations indicate classes that are able to participate in logout handling. They are expected to be invoked to perform necessary clean-up. As such they should not throw exceptions. Various implementations are provided:

Please see Section 17.4, “Remember-Me Interfaces and Implementations” for details.

Instead of providing LogoutHandler implementations directly, the fluent API also provides shortcuts that provide the respective LogoutHandler implementations under the covers. E.g. deleteCookies() allows specifying the names of one or more cookies to be removed on logout success. This is a shortcut compared to adding a CookieClearingLogoutHandler.

5.5.2 LogoutSuccessHandler

The LogoutSuccessHandler is called after a successful logout by the LogoutFilter, to handle e.g. redirection or forwarding to the appropriate destination. Note that the interface is almost the same as the LogoutHandler but may raise an exception.

The following implementations are provided:

As mentioned above, you don’t need to specify the SimpleUrlLogoutSuccessHandler directly. Instead, the fluent API provides a shortcut by setting the logoutSuccessUrl(). This will setup the SimpleUrlLogoutSuccessHandler under the covers. The provided URL will be redirected to after a logout has occurred. The default is /login?logout.

The HttpStatusReturningLogoutSuccessHandler can be interesting in REST API type scenarios. Instead of redirecting to a URL upon the successful logout, this LogoutSuccessHandler allows you to provide a plain HTTP status code to be returned. If not configured a status code 200 will be returned by default.

5.5.3 Further Logout-Related References

5.6 Authentication

Thus far we have only taken a look at the most basic authentication configuration. Let’s take a look at a few slightly more advanced options for configuring authentication.

5.6.1 In-Memory Authentication

We have already seen an example of configuring in-memory authentication for a single user. Below is an example to configure multiple users:

@Bean
public UserDetailsService userDetailsService() throws Exception {
	InMemoryUserDetailsManager manager = new InMemoryUserDetailsManager();
	manager.createUser(User.withUsername("user").password("password").roles("USER").build());
	manager.createUser(User.withUsername("admin").password("password").roles("USER","ADMIN").build());
	return manager;
}

5.6.2 JDBC Authentication

You can find the updates to support JDBC based authentication. The example below assumes that you have already defined a DataSource within your application. The jdbc-javaconfig sample provides a complete example of using JDBC based authentication.

@Autowired
private DataSource dataSource;

@Autowired
public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
	auth
		.jdbcAuthentication()
			.dataSource(dataSource)
			.withDefaultSchema()
			.withUser("user").password("password").roles("USER").and()
			.withUser("admin").password("password").roles("USER", "ADMIN");
}

5.6.3 LDAP Authentication

You can find the updates to support LDAP based authentication. The ldap-javaconfig sample provides a complete example of using LDAP based authentication.

@Autowired
private DataSource dataSource;

@Autowired
public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
	auth
		.ldapAuthentication()
			.userDnPatterns("uid={0},ou=people")
			.groupSearchBase("ou=groups");
}

The example above uses the following LDIF and an embedded Apache DS LDAP instance.

users.ldif. 

dn: ou=groups,dc=springframework,dc=org
objectclass: top
objectclass: organizationalUnit
ou: groups

dn: ou=people,dc=springframework,dc=org
objectclass: top
objectclass: organizationalUnit
ou: people

dn: uid=admin,ou=people,dc=springframework,dc=org
objectclass: top
objectclass: person
objectclass: organizationalPerson
objectclass: inetOrgPerson
cn: Rod Johnson
sn: Johnson
uid: admin
userPassword: password

dn: uid=user,ou=people,dc=springframework,dc=org
objectclass: top
objectclass: person
objectclass: organizationalPerson
objectclass: inetOrgPerson
cn: Dianne Emu
sn: Emu
uid: user
userPassword: password

dn: cn=user,ou=groups,dc=springframework,dc=org
objectclass: top
objectclass: groupOfNames
cn: user
uniqueMember: uid=admin,ou=people,dc=springframework,dc=org
uniqueMember: uid=user,ou=people,dc=springframework,dc=org

dn: cn=admin,ou=groups,dc=springframework,dc=org
objectclass: top
objectclass: groupOfNames
cn: admin
uniqueMember: uid=admin,ou=people,dc=springframework,dc=org

5.6.4 AuthenticationProvider

You can define custom authentication by exposing a custom AuthenticationProvider as a bean. For example, the following will customize authentication assuming that SpringAuthenticationProvider implements AuthenticationProvider:

[Note]Note

This is only used if the AuthenticationManagerBuilder has not been populated

@Bean
public SpringAuthenticationProvider springAuthenticationProvider() {
	return new SpringAuthenticationProvider();
}

5.6.5 UserDetailsService

You can define custom authentication by exposing a custom UserDetailsService as a bean. For example, the following will customize authentication assuming that SpringDataUserDetailsService implements UserDetailsService:

[Note]Note

This is only used if the AuthenticationManagerBuilder has not been populated and no AuthenticationProviderBean is defined.

@Bean
public SpringDataUserDetailsService springDataUserDetailsService() {
	return new SpringDataUserDetailsService();
}

You can also customize how passwords are encoded by exposing a PasswordEncoder as a bean. For example, if you use bcrypt you can add a bean definition as shown below:

@Bean
public BCryptPasswordEncoder passwordEncoder() {
	return new BCryptPasswordEncoder();
}

5.6.6 LDAP Authentication

5.7 Multiple HttpSecurity

We can configure multiple HttpSecurity instances just as we can have multiple <http> blocks. The key is to extend the WebSecurityConfigurerAdapter multiple times. For example, the following is an example of having a different configuration for URL’s that start with /api/.

@EnableWebSecurity
public class MultiHttpSecurityConfig {
	@Bean
	public UserDetailsService userDetailsService() throws Exception {
		InMemoryUserDetailsManager manager = new InMemoryUserDetailsManager();
		manager.createUser(User.withUsername("user").password("password").roles("USER").build());
		manager.createUser(User.withUsername("admin").password("password").roles("USER","ADMIN").build());
		return manager;
	}

	@Configuration
	@Order(1)                                                        1
	public static class ApiWebSecurityConfigurationAdapter extends WebSecurityConfigurerAdapter {
		protected void configure(HttpSecurity http) throws Exception {
			http
				.antMatcher("/api/**")                               2
				.authorizeRequests()
					.anyRequest().hasRole("ADMIN")
					.and()
				.httpBasic();
		}
	}

	@Configuration                                                   3
	public static class FormLoginWebSecurityConfigurerAdapter extends WebSecurityConfigurerAdapter {

		@Override
		protected void configure(HttpSecurity http) throws Exception {
			http
				.authorizeRequests()
					.anyRequest().authenticated()
					.and()
				.formLogin();
		}
	}
}

Configure Authentication as normal

1

Create an instance of WebSecurityConfigurerAdapter that contains @Order to specify which WebSecurityConfigurerAdapter should be considered first.

2

The http.antMatcher states that this HttpSecurity will only be applicable to URLs that start with /api/

3

Create another instance of WebSecurityConfigurerAdapter. If the URL does not start with /api/ this configuration will be used. This configuration is considered after ApiWebSecurityConfigurationAdapter since it has an @Order value after 1 (no @Order defaults to last).

5.8 Method Security

From version 2.0 onwards Spring Security has improved support substantially for adding security to your service layer methods. It provides support for JSR-250 annotation security as well as the framework’s original @Secured annotation. From 3.0 you can also make use of new expression-based annotations. You can apply security to a single bean, using the intercept-methods element to decorate the bean declaration, or you can secure multiple beans across the entire service layer using the AspectJ style pointcuts.

5.8.1 EnableGlobalMethodSecurity

We can enable annotation-based security using the @EnableGlobalMethodSecurity annotation on any @Configuration instance. For example, the following would enable Spring Security’s @Secured annotation.

@EnableGlobalMethodSecurity(securedEnabled = true)
public class MethodSecurityConfig {
// ...
}

Adding an annotation to a method (on a class or interface) would then limit the access to that method accordingly. Spring Security’s native annotation support defines a set of attributes for the method. These will be passed to the AccessDecisionManager for it to make the actual decision:

public interface BankService {

@Secured("IS_AUTHENTICATED_ANONYMOUSLY")
public Account readAccount(Long id);

@Secured("IS_AUTHENTICATED_ANONYMOUSLY")
public Account[] findAccounts();

@Secured("ROLE_TELLER")
public Account post(Account account, double amount);
}

Support for JSR-250 annotations can be enabled using

@EnableGlobalMethodSecurity(jsr250Enabled = true)
public class MethodSecurityConfig {
// ...
}

These are standards-based and allow simple role-based constraints to be applied but do not have the power Spring Security’s native annotations. To use the new expression-based syntax, you would use

@EnableGlobalMethodSecurity(prePostEnabled = true)
public class MethodSecurityConfig {
// ...
}

and the equivalent Java code would be

public interface BankService {

@PreAuthorize("isAnonymous()")
public Account readAccount(Long id);

@PreAuthorize("isAnonymous()")
public Account[] findAccounts();

@PreAuthorize("hasAuthority('ROLE_TELLER')")
public Account post(Account account, double amount);
}

5.8.2 GlobalMethodSecurityConfiguration

Sometimes you may need to perform operations that are more complicated than are possible with the @EnableGlobalMethodSecurity annotation allow. For these instances, you can extend the GlobalMethodSecurityConfiguration ensuring that the @EnableGlobalMethodSecurity annotation is present on your subclass. For example, if you wanted to provide a custom MethodSecurityExpressionHandler, you could use the following configuration:

@EnableGlobalMethodSecurity(prePostEnabled = true)
public class MethodSecurityConfig extends GlobalMethodSecurityConfiguration {
	@Override
	protected MethodSecurityExpressionHandler createExpressionHandler() {
		// ... create and return custom MethodSecurityExpressionHandler ...
		return expressionHandler;
	}
}

For additional information about methods that can be overridden, refer to the GlobalMethodSecurityConfiguration Javadoc.

5.9 Post Processing Configured Objects

Spring Security’s Java Configuration does not expose every property of every object that it configures. This simplifies the configuration for a majority of users. Afterall, if every property was exposed, users could use standard bean configuration.

While there are good reasons to not directly expose every property, users may still need more advanced configuration options. To address this Spring Security introduces the concept of an ObjectPostProcessor which can be used to modify or replace many of the Object instances created by the Java Configuration. For example, if you wanted to configure the filterSecurityPublishAuthorizationSuccess property on FilterSecurityInterceptor you could use the following:

@Override
protected void configure(HttpSecurity http) throws Exception {
	http
		.authorizeRequests()
			.anyRequest().authenticated()
			.withObjectPostProcessor(new ObjectPostProcessor<FilterSecurityInterceptor>() {
				public <O extends FilterSecurityInterceptor> O postProcess(
						O fsi) {
					fsi.setPublishAuthorizationSuccess(true);
					return fsi;
				}
			});
}

5.10 Custom DSLs

You can provide your own custom DSLs in Spring Security. For example, you might have something that looks like this:

public class MyCustomDsl extends AbstractHttpConfigurer<CorsConfigurerMyCustomDsl, HttpSecurity> {
	private boolean flag;

	@Override
	public void init(H http) throws Exception {
		// any method that adds another configurer
		// must be done in the init method
		http.csrf().disable();
	}

	@Override
	public void configure(H http) throws Exception {
		ApplicationContext context = http.getSharedObject(ApplicationContext.class);

		// here we lookup from the ApplicationContext. You can also just create a new instance.
		MyFilter myFilter = context.getBean(MyFilter.class);
		myFilter.setFlag(flag);
		http.addFilterBefore(myFilter, UsernamePasswordAuthenticationFilter.class);
	}

	public MyCustomDsl flag(boolean value) {
		this.flag = value;
		return this;
	}

	public static MyCustomDsl customDsl() {
		return new MyCustomDsl();
	}
}
[Note]Note

This is actually how methods like HttpSecurity.authorizeRequests() are implemented.

The custom DSL can then be used like this:

@EnableWebSecurity
public class Config extends WebSecurityConfigurerAdapter {
	@Override
	protected void configure(HttpSecurity http) throws Exception {
		http
			.apply(customDsl())
				.flag(true)
				.and()
			...;
	}
}

The code is invoked in the following order:

  • Code in `Config`s configure method is invoked
  • Code in `MyCustomDsl`s init method is invoked
  • Code in `MyCustomDsl`s configure method is invoked

If you want, you can have WebSecurityConfiguerAdapter add MyCustomDsl by default by using SpringFactories. For example, you would create a resource on the classpath named META-INF/spring.factories with the following contents:

META-INF/spring.factories. 

org.springframework.security.config.annotation.web.configurers.AbstractHttpConfigurer = sample.MyCustomDsl

Users wishing to disable the default can do so explicitly.

@EnableWebSecurity
public class Config extends WebSecurityConfigurerAdapter {
	@Override
	protected void configure(HttpSecurity http) throws Exception {
		http
			.apply(customDsl()).disable()
			...;
	}
}