H2 Console Cant see tables created by JAVA

问题

I have downloaded the H2 console from http://www.h2database.com/html/download.html
and I have configured the URL in my jdbc.properties file
to jdbc:h2:c:/data/Messaging.

I am using the same URL in the file to connect to the database but I cannot see the tables; I can only see the Information Schema and when I try to select * from tables in it I cannot see the tables neither.

Does anybody have any idea what could be wrong?

回答1:

One tricky thing is that the H2 console will not give you an error if you try to connect to a JDBC URL that doesn't exist. It will instead create a new database at that URL! To connect to the in memory DB, use this JDBC URL (http://localhost:8080/h2-console is the default console):

jdbc:h2:mem:testdb

If you were to enter something like jdbc:h2:~/test then a test.mv file would be created under your home directory. But your application would still be using the in memory database.

The console is available if you have the h2 dependency in your pom, and also the spring developer tools dependency. If you don't have the tools dependency, then you can also see it by having the h2 dependency and adding the following to your application.properties file:

spring.h2.console.enabled=true  #not needed if you have spring-boot-devtools dependency

If you want the db as a file, and not in memory, add the following to applications.properties:

spring.datasource.url=jdbc:h2:~/test_db  #You will see the file in your home directory.

H2 isn't meant for persisted data, but if you want to persist for testing purposes, then add:

spring.jpa.hibernate.ddl-auto = update

Then start up the app, and at the console, use this JDBC URL:

jdbc:h2:~/test_db

In case you were wondering, I only have 1 entry in application.properties (for the database file) and here are my dependencies:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <optional>true</optional>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
</dependency>

回答2:

Based on your question, it doesn't look like you fell victim to this particular pitfall, but this thread ended up helping me nail down the issue, so I am recording the solution here for posterity since it may help others with the same problem.

I also found that when I tried to open my database with the H2 console that I got what appeared to be a blank H2 database (basically, just an INFORMATION_SCHEMA table). While double-checking that I got the name of the DB correct (mydb.mv.db), I discovered that the H2 console had created a second database file, mydb.mv.db.mv.db. Odd.

It turns out that the H2 Console expects you to omit the suffix .mv.db from the filename. Since I hadn't, it was looking for mydb.mv.db.mv.db. Changing the JDBC string to jdbc:h2:mydb solved the problem and I could then open the file from the H2 Console.

回答3:

Had the same Problem.

This solved it for me: Why is my embedded h2 program writing to a .mv.db file

Just added ;MV_STORE=FALSE and ;MVCC=FALSE to the jdbc url and everything worked just fine.

回答4:

This is how you enable memory enable database using h2 module. You need to ensure the following things

You had class that has @Entity annotations.
you need to enable the following in application.properties file spring.h2.console.enabled=true
Run Spring Boot and enter the following URL localhost:8080/h2-console
This will show a connection screen. Enter the following changes in the JDBC URL: -> jdbc:h2:mem:testdb 5.Hit the connection button

Salam

回答5:

I have used the below and I see my table get created.

spring.datasource.url=jdbc:h2:mem:testdb;DB_CLOSE_ON_EXIT=FALSE
spring.h2.console.enabled=true
spring.h2.console.path=/h2console
spring.datasource.username=sa
spring.datasource.password=
spring.datasource.driverClassName=org.h2.Driver
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.H2Dialect