Spring 引导 - 摆脱 Hikari 数据源并使用 H2

Question

I would like to use an H2 database in a Spring Boot application.

This is what I have in application.properties:

spring.datasource.name=testdb
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=whydoesthishavetobe
spring.datasource.password=sodifficult
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

This are the relevant lines in the build.gradle file:

    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    runtimeOnly 'com.h2database:h2'

When I check the connection for the H2 database, it's all good.

But despite this, when I POST new entities into the application, I see nothing getting created in the H2 database, and Hikari data source is getting used instead in the background, as I see from the logs.

Why is Spring ignoring the application.properties file and not using the H2 data source? How can I force it to use the H2 data source?

This is Spring Boot 2.3.4.RELEASE.

Answer 1

I guess you have multiple datasources and a datasource other tha H2 is being autowired as default.As Hirakicp is a connection pool not a db. U need not get rid of Hirakicp rather set h2 datasources as primary

The below solution should work if you have multiple datasources,

If you have multiple data source beans configured, it's just that spring is autowiring other data source to be used as a default source.

using @Primary annotation while declaring H2 Datasource bean should solve this. Using this annotation will force spring to autowire the datult to h2 datasource.

in case you have not declared a datasource bean for H2 but have other datasource beans, you will need to declare the h2 bean and set it as primary using @primary annotation.

note - Hirakicp is a db connection object not a db.

Example -

    @Bean("one")
    public BasicDataSource dataSourceOne() {
        BasicDataSource basicDataSource = new BasicDataSource();
        basicDataSource.setUrl(env.getProperty("spring.a.connectionUrl"));
        basicDataSource.setDriverClassName(env.getProperty("spring.a.DriverClass"));
        basicDataSource.setUsername(env.getProperty("spring.a.username"));
        basicDataSource.setPassword(env.getProperty("spring.a.password"));
        //  basicDataSource.setMaxActive(2);
        return basicDataSource;

    }

    @Primary
    @Bean("two")
    public BasicDataSource dataSourceTwo() {
        BasicDataSource basicDataSource = new BasicDataSource();
        basicDataSource.setUrl(env.getProperty("spring.u.connectionUrl"));
        basicDataSource.setDriverClassName(env.getProperty("spring.u.DriverClass"));
        basicDataSource.setUsername(env.getProperty("spring.u.username"));
        basicDataSource.setPassword(env.getProperty("spring.u.password"));
        return basicDataSource;

    }

Answer 2

I think this is happening because SpringBoot application creates its own in-memory embedded database while your database client creates its own in-memory embedded database.

I suggest you to change the database from in-memory to filesystem and see if the application and your database client shows the same data.

spring.datasource.url=jdbc:h2:file:/data/sample/testdb

You only need to change the database url to make it a file based database.

If you need to proceed with in-memory approach, you can connect to that via tcp so that both your application and client can use the same database.

spring.datasource.url=jdbc:h2:tcp://localhost/mem:testdb

Answer 3

What do you mean by Why is Spring ignoring the application.properties file and not using the H2 data source? Hikari is connection pool, not a datasource. If you would like to provide your own datasource, you have to inject a bean with the configuration of your interest.

Connection pool A connection pool is a cache of database connections maintained so that the connections can be reused when future requests to the database are required.

Datasource Is where data that is being used to run a report or gain information is originating from.

Check here for more on connection pools: https://www.baeldung.com/java-connection-pooling

But, if it the logging that you don't like, you can set the logger to error with org.zaxxer.hikari=error