Spring Boot - Migration / Data Source

Implement H2

In this case first will be use H2

• Add H2 to pom.xml, in the dependencies section.

        <dependency>

          <groupId>org.springframework.boot</groupId>

          <artifactId>spring-boot-starter-data-jpa</artifactId>

</dependency>

        <dependency>

<groupId>com.h2database</groupId>

<artifactId>h2</artifactId>

</dependency>

• Modify application.properties file adding the following properties:

The files is in scr/main/resources

• spring.h2.console.enabled=true
• spring.h2.console.path=/h2

The value in path property is the URL to see H2 database console.
Ex. http://localhost:8080/h2/

Migration

Use Flyway

Add in pom.xaml the dependency

<dependency>

                 <groupId>org.flywaydb</groupId>

                 <artifactId>flyway-core</artifactId>

</dependency>

• Create the folder in scr/resources
• db -> 
• migration

• Add to the application.properties
• flyway.baseline-description=true

• spring.jpa.hibernate.ddl-auto=false;

• Create file
• V2_create_db.sql

Always start the file as V2__

Ex.

CREATE TABLE SHIPWRECK(

   ID INT AUTO_INCREMENT,

   NAME VARCHAR(255),

   DESCRIPTION VARCHAR(2000),

   CONDITION VARCHAR(255),

   DEPTH INT,

   LATITUDE DOUBLE,

   LONGITUDE DOUBLE,

   YEAR_DISCOVERED INT

);

Datasource Configuration

Add in application properties:

spring.datasource.url=jdbc:h2:file:~/dasboot

spring.datasource.username=sa

spring.datasource.password=

spring.datasource.driver-class-name=org.h2.Driver

In this case the url is specifying that the db will be stored in a file


Other configurations:

spring.datasource.max-active=10

spring.datasource.max-idle=8

spring.datasource.max-wait=10000

spring.datasource.min-evictable-idle-time-millis=1000

spring.datasource.min-idle=8

spring.datasource.time-between-eviction-runs-millis=1

Datasource for Spring

• Create a folder for the configuration in
• scr/main/java
• <project>
• config

• Create a class as <Name>Configuration
• Add above the class the annotation
• @Configuration
• Create a DataSource Bean 

• @Bean
  @ConfigurationProperties(prefix="spring.datasource")
  @Primary
  public DataSource dataSource(){
  return DataSourceBuilder.create().build();
  }
• Second Datasource
• @Bean
  @ConfigurationProperties(prefix="datasource.flyway")
  @Primary
  public DataSource flyWayDataSource(){
  return DataSourceBuilder.create().build();
  }

• The @Primary annotation is to avoid problems when many datasources are configured
• The prefix is how is defined in the application.properties