FAQ Questions on Spring Boot

How to control logging with Spring Boot?

By default, the SLF4j Logging is included in the Spring Boot starter package. To enable logging, create a application.properties file in the root of the resources folder.

1. application.properties

logging.level.org.springframework.web=ERROR

logging.level.com.waheedtechblog=DEBUG

# Logging pattern for the console

logging.pattern.console= "%d{yyyy-MM-dd HH:mm:ss} - %msg%n"

# Logging pattern for file

logging.pattern.file= "%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n"

logging.file=/Users/waheed/application.log

Similarly we can configure in application.yml as well.

2. application.yml

logging:

  level:

    org.springframework.web: ERROR

    com.waheedtechblog: DEBUG

  pattern:

    console: "%d{yyyy-MM-dd HH:mm:ss} - %msg%n"

    file: "%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n"

  file: /Users/waheed/application.log

3.  Classic Logback.xml

If you don’t like the Spring Boot logging template, just create a standard logback.xml in the root of the resources folder or root of the classpath. This will override the Spring Boot logging template.

How to run Spring boot application to custom port ?
In application.properties, add following property.

            Server.port=9090

How to configure datasource using Spring boot?
• Use either spring-boot-starter-jdbc or spring-boot-starterdata-jpa and include a JDBC driver on classpath
• Declare properties

1.      spring.datasource.url=jdbc:mysql://localhost/test

2.      spring.datasource.username=dbuser

3.      spring.datasource.password=dbpass

4.      spring.datasource.driver-class-name=com.mysql.jdbc.Driver

– Spring Boot will create a DataSource with properties set
– Will even use a connection pool if the library is found on the classpath!

How to change Context Path?

To change the context path, update server.contextPath properties either in application.properties file or application.yaml file.

Application.properties

server.port=8080

server.contextPath=/application

application.yaml

server:

  port: 8080

  contextPath: /application

Database access with Spring boot

The simplest way of creating Spring boot with MySQL application is via Spring starter project using STS (Spring Tool Suite) IDE.

Steps:

• Create a new project by selecting spring starter project wizard
• Select project type as Maven, provide project name, packaging, and Java version etc.

• Select spring boot version and project dependencies

• After finishing, It will create the project structure with all required dependency.
• Configure MySQL configuration in application.properties file

• Now, Create the @Entity model (User) which should be persisted in the database. Hibernate will automatically translate entity class into a table.

• Create the repository (UserRepository.java). The Repository interface will be automatically implemented by Spring in a bean with the same name with changing case. For UserRepository, the bean name will be userRepository.

• To handle HTTP request, Create a Controller class (UserController.java) having method POST and GET operations.

• Now run the SpringBootMySQLApplication.java as a Java application. It will start the tomcat server on default port i.e. 8080
• Open browser and hit url http://localhost:8080/users

• As there is no user present into the database that is why we see empty list. Let's add few users using POSTMAN.
• To add a user, Open Postman and run below http request

•  Now again Open browser and hit url http://localhost:8080/users

• Congratulations! We've just developed a Spring application which is bound to a MySQL database, Ready for production! Source code can be downloaded from GITHUB.

Happy Coding...!!!

Spring Boot application Example

As we know that there are various ways for creating Spring Boot application. For this sample application, I am going to use STS (Spring Tool Suite) IDE.

Steps:

• Create a new project by selecting spring starter project wizard

• Select project type as Maven, provide project name, packaging, and Java version etc.

• Select spring boot version and project dependencies

• After finishing, you can see the project structure as shown below

• Spring boot generates a Java file in the src/main/java directory, pom.xml file with all required dependency. 

• To handle HTTP request, Create a Controller class

• Now run the SpringBootExampleApplication.java as a Java application. It will start the tomcat server on default port i.e. 8080

• Open browser and hit url http://localhost:8080/application

Note:

By Default, Application will start on port 8080 but can override by adding server.port to application.properties file.

Happy Coding..!!!