This guide describes how to use Spring Session to transparently leverage a relational database to back a web application’s HttpSession
when using Spring Boot.
The completed guide can be found in the httpsession-jdbc-boot sample application. |
Updating Dependencies
Before you use Spring Session, you must ensure to update your dependencies. We assume you are working with a working Spring Boot web application. If you are using Maven, ensure to add the following dependencies:
<dependencies>
<!-- ... -->
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-jdbc</artifactId>
<version>1.2.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
</dependencies>
Spring Configuration
After adding the required dependencies, we can create our Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the HttpSession
implementation with an implementation backed by Spring Session.
Add the following Spring Configuration:
@EnableJdbcHttpSession (1)
public class HttpSessionConfig {
}
1 | The @EnableJdbcHttpSession annotation creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter.
The filter is what is in charge of replacing the HttpSession implementation to be backed by Spring Session.
In this instance Spring Session is backed by a relational database. |
Configuring the DataSource
Spring Boot automatically creates a DataSource
that connects Spring Session to an embedded instance of H2 database.
In a production environment you need to ensure to update your configuration to point to your relational database.
For example, you can include the following in your application.properties
spring.datasource.url=jdbc:postgresql://localhost:5432/myapp spring.datasource.username=myapp spring.datasource.password=secret
For more information, refer to Configure a DataSource portion of the Spring Boot documentation.
Servlet Container Initialization
Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, Spring needs to load our Config
class.
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
Fortunately, Spring Boot takes care of both of these steps for us.
httpsession-jdbc-boot Sample Application
The httpsession-jdbc-boot Sample Application demonstrates how to use Spring Session to transparently leverage H2 database to back a web application’s HttpSession
when using Spring Boot.
Running the httpsession-jdbc-boot Sample Application
You can run the sample by obtaining the source code and invoking the following command:
$ ./gradlew :samples:httpsession-jdbc-boot:bootRun
You should now be able to access the application at http://localhost:8080/
Exploring the security Sample Application
Try using the application. Enter the following to log in:
-
Username user
-
Password password
Now click the Login button.
You should now see a message indicating your are logged in with the user entered previously.
The user’s information is stored in H2 database rather than Tomcat’s HttpSession
implementation.
How does it work?
Instead of using Tomcat’s HttpSession
, we are actually persisting the values in H2 database.
Spring Session replaces the HttpSession
with an implementation that is backed by a relational database.
When Spring Security’s SecurityContextPersistenceFilter
saves the SecurityContext
to the HttpSession
it is then persisted into H2 database.
When a new HttpSession
is created, Spring Session creates a cookie named SESSION in your browser that contains the id of your session.
Go ahead and view the cookies (click for help with Chrome or Firefox).
If you like, you can easily remove the session using H2 web console available at: http://localhost:8080/h2-console/ (use jdbc:h2:mem:testdb
for JDBC URL)
Now visit the application at http://localhost:8080/ and observe that we are no longer authenticated.