As a Java developer, you're probably no stranger to the Spring Framework. Spring Boot is an extension of the Spring Framework that makes it easy to create stand-alone, production-grade Spring-based applications.
While the out-of-the-box configuration of a Spring Boot application is usually enough for most applications, there are cases where you might need to tweak the configuration. For example, if you're developing a microservice that will be deployed to a cloud environment, you might want to configure your application to use a session stateless mode, which is more appropriate for a stateless environment.
In this post, we'll take a look at some of the most common Spring Boot configuration settings and how to configure them. We'll also take a look at some of the best practices for securing a Spring Boot application.
Spring Boot applications are typically configured using a application.properties
or application.yml
file. The application.properties
file is used for simple properties, while the application.yml
file can be used for more complex configurations. We'll take a look at both files, starting with the application.properties
file.
The application.properties
file is located in the src/main/resources
directory. This file contains a list of key-value pairs, where the key is the name of the property and the value is the value of the property.
For example, let's say we want to configure our application to use a session stateless mode. We would add the following to our application.properties
file:
spring.session.mode=stateless
Similarly, if we want to configure our application to use a specific datasource, we can add the following to our application.properties
file:
spring.datasource.url=jdbc:mysql://localhost:3306/mydatabase
spring.datasource.username=myusername
spring.datasource.password=mypassword
The application.yml
file is located in the src/main/resources
directory. This file can be used for more complex configurations, such as configuring multiple datasources or configuring aspects of the Spring Security configuration.
For example, let's say we want to configure our application to use multiple datasources. We would add the following to our application.yml
file:
spring:
datasource:
primary:
url: jdbc:mysql://localhost:3306/mydatabase
username: myusername
password: mypassword
secondary:
url: jdbc:mysql://localhost:3306/myotherdatabase
username: myotherusername
password: myotherpassword
Similarly, if we want to configure our application to use a specific version of the Hibernate JPA provider, we can add the following to our application.yml
file:
spring:
jpa:
hibernate:
ddl-auto: validate
properties:
hibernate:
jpa.provider: org.hibernate.jpa.HibernatePersistenceProvider
jpa.properties.hibernate.dialect: org.hibernate.dialect.MySQL5Dialect
Now that we've looked at how to configure a Spring Boot application, let's take a look at how to secure it.
Spring Boot provides a number of features that make it easy to secure your application. For example, Spring Boot automatically configures a SecurityProperties
bean when it detects the spring-boot-starter-security
dependency in your project. Additionally, Spring Boot provides a number of auto-configuration classes that make it easy to configure security for your application.
In this section, we'll take a look at some of the most common Spring Boot security features and how to configure them.
One of the most common security concerns for web applications is ensuring that data is transmitted securely. HTTPS is the most common way to achieve this, and Spring Boot makes it easy to enable HTTPS for your application.
To enable HTTPS, you need to first configure a keystore. A keystore is a file that contains your application's SSL/TLS certificate and private key. You can generate a self-signed keystore using the Java keytool
utility. For example, to generate a keystore with the mykeystore.jks
file name, you can use the following command:
keytool -genkeypair -alias myalias -keyalg RSA -keysize 2048 -storetype PKCS12 -keystore mykeystore.jks -validity 365
Once you have generated a keystore, you can configure Spring Boot to use it by adding the following to your application.properties
file:
server.ssl.key-store: mykeystore.jks
server.ssl.key-store-password: mypassword
server.ssl.keyAlias: myalias
Alternatively, you can configure Spring Boot to use HTTPS by adding the following to your application.yml
file:
server:
ssl:
key-store: mykeystore.jks
key-store-password: mypassword
keyAlias: myalias
One of the most common ways to authenticate users is to use a database authentication provider. Database authentication providers typically use a database table to store username and password hash values. When a user attempts to login, the authentication provider will query the database to see if there is a matching username and password hash. If there is a match, the user will be authenticated.
To configure a database authentication provider, you first need to create a database table to store the username and password hash values. You can use the following SQL to create a database table:
CREATE TABLE users (
username VARCHAR(255) NOT NULL,
password VARCHAR(255) NOT NULL,
PRIMARY KEY (username)
);
Once you have created the database table, you can configure Spring Boot to use it by adding the following to your application.properties
file:
spring.security.user.name=myusername
spring.security.user.password=mypassword
Alternatively, you can configure Spring Boot to use a database authentication provider by adding the following to your application.yml
file:
spring:
security:
user:
name: myusername
password: mypassword
Spring Boot provides a number of auto-configuration classes that make it easy to configure Spring Security for your application. For example, Spring Boot automatically configures a WebSecurityConfigurerAdapter
when it detects the spring-boot-starter-security
dependency in your project.
The WebSecurityConfigurerAdapter
provides a number of methods that can be used to configure Spring Security for your application. For example, the configure(HttpSecurity)
method can be used to configure how web resources are secured.
Additionally, Spring Boot provides a number of HASmatchers that can be used to restrict access to web resources. For example, the hasIpAddress()
matcher can be used to restrict access to a web resource to only clients with a specific IP address.
To learn more about configuring Spring Security for a Spring Boot application, check out the Spring Boot Security Reference Guide.
In this post, we've looked at how to configure a Spring Boot application. We've also looked at how to secure a Spring Boot application.
While the out-of-the-box configuration of a Spring Boot application is usually enough for most applications, there are cases where you might need to tweak the configuration. For example, if you're developing a microservice that will be deployed to a cloud environment, you might want to configure your application to use a session stateless mode, which is more appropriate for a stateless environment.
Additionally, Spring Boot provides a number of features that make it easy to secure your application. For example, Spring Boot automatically configures a SecurityProperties
bean when it detects the spring-boot-starter-security
dependency in your project. Additionally, Spring Boot provides a number of auto-configuration classes that make it easy to configure security for your application.