Spring Boot configuration through - application.properties

Spring boot comes with preconfigured application. We don't need to change anything to simply run the code. But if we want to change some of those default configurations to some customized configurations, we can use a file this method. For example if we want to connect to database and access the data, Spring Boot automatically provides configuration for almost anything, but, we also need to provide our database credentials, context path, etc. to run the program. So in that scenario, we need to provide those information to the application. There is a file named application.properties which can be used to store all the configuration properties in the spring boot application. These properties can include the port number on which we can run spring boot program, view settings, database and JPA settings and more. This file is in the folder /src/main/resources. There is also another file named application.yml which can be used to change the configuration. But the most common is using application.properties. There are different types of properties that can be changed through this file

Core properties

Cache properties

Mail properties

JSON properties

Data properties

Transaction properties

Data migration properties

Integration properties

Web properties

Templating properties

Server properties

Security properties

RSocket properties

Actuator properties

Devtools properties

Testing properties

We describe wome common properties we encounter while coding spring boot application.

Changing port number on which we run spring boot application

Spring boot comes with preconfigured port number on which the application is run. The default port number is 8080. But if the port is already being used or we want to use other port. e.g. 9000, then we can use this property to change it. server.port = 9000

Change the view suffix and prefix

The default folder containing view files is /src/webapps. If we want to put our view files in /src/webapps/views, then the first command does this. The second command tells spring to take .jsp as the defailt suffix or default extension that is used as view file spring.mvc.view.prefix=/views/ spring.mvc.view.suffix=.jsp

Context path

By default the context path is not available. If we want it, we can use following server.servlet.context-path=myapp

Database url configuration

We also need to use database confituration to use database with our spring application. Following properties are used to change the database credentials, and jpa properties. spring.datasource.url=jdbc:mysql://localhost:3306/yourDatabaseName?useSSL=false spring.datasource.username=root spring.datasource.password=root spring.datasource.driverClassName=com.mysql.jdbc.Driver spring.jpa.hibernate.ddl-auto=update