Spring Boot 中嵌入式 H2 数据库的默认名称是什么？

Question

As I've read the default name of the embedded H2 database in Spring Boot should be testdb , but if I try to connect to with the H2 Console, I get the following error:

Database "mem:testdb" not found, either pre-create it or allow remote database creation (not recommended in secure environments)

It works only if I set the name explicitly in the application.properties with the following parameter:

spring.datasource.url=jdbc:h2:mem:testdb

Since the application can connect to the embedded database without this configuration, there must be a different default name. But what is the default name of the automatically configured database?

Answer 1

Enable h2 console in application.properties as jurez said

spring.h2.console.enabled=true
spring.h2.console.path=/h2-console
spring.jpa.show-sql=true

and then when you run the application in the console you will see something like this:

H2 console available at '/h2-console'. Database available at 'jdbc:h2:mem:2f5b7da9-0cd2-4fdd-98d2-5ef5f76391bc'

then you can use this JDBC URL to connect to the database from the h2-console

http://localhost:8080/h2-console

jdbc:h2:mem:2f5b7da9-0cd2-4fdd-98d2-5ef5f76391bc

you can specify your own name by adding the following property in the application.property file

spring.datasource.url=jdbc:h2:mem:testdb

remember since this is an in-memory database it will be dropped and recreated every time you run your application

h2 also has a persistent mode but it is not recommended, you can do that by adding the following configurations taken from the following tutorial Spring Boot and H2 in memory database - Why, What and How?

spring.datasource.name=yourdbname
spring.datasource.driverClassName=org.h2.Driver
 
spring.datasource.initialize=false
spring.datasource.url=jdbc:h2:file:~/yourdbname;DB_CLOSE_ON_EXIT=FALSE;IFEXISTS=TRUE;DB_CLOSE_DELAY=-1;
 
spring.jpa.hibernate.ddl-auto = update

Answer 2

By default, memory databases are only accessible to the process in which they are running.

If you want to access it from H2 Console, you need to enable it in application.properties:

spring.h2.console.enabled=true