Frequently when developing Spring based applications, you will use the H2 in memory database during your development process.
With H2, your database is created by Hibernate every time you start the application. Thus, the database is brought up in a known and consistent state.
It also allows you to develop and test your JPA mappings. H2 ships with a web based database console, which you can use while your application is under development.
It is a convenient way to view the tables created by Hibernate and run queries against the in memory database. Here is an example of the H2 database console. Spring Boot has great built in support for the H2 database. This is needed to support the changes we need to make to the Spring Boot configuration. Just remove the scope statement and Maven will change to the default of compile. If you are not using Spring Security with the H2 database console, this is all you need to do.
With its default settings under Spring Boot, Spring Security will block access to H2 database console. To enable access to the H2 database console under Spring Security you need to change three things:. These settings are only to support development of a Spring Boot web application and enable access to the H2 database console.
Before you login, be sure you have the proper H2 database settings. The Grails team added the H2 database console with the release of Grails 2. I quickly fell in love with this feature.
The H2 database console is a great tool to have at your disposal. You can check your database right from the IDE. But nice blogpost anyway. Thx for that. I did translate to korean. Thank you for this post. Quite useful. Just want to add, maybe somebody find it useful. Hei, Just now, I found a more convenient solution to access h2 web console, this time you need do nothing. As of Spring Boot 1. M3, the H2 console can be auto-configured.
You are developing a web app Spring Boot Dev Tools are enabled H2 is on the classpath Check out this part of the documentation for all the details. WebServlet ; h2ConsoleServlet. I had deployed this app both in local box and also in IBM Bluemix. FYI, I have updated import org. ServletRegistrationBean; to import org. For my spring boot application, adding below to application.
Any idea why? Hi, looks like the ServletRegistrationBean is no longer available with version 2. Is there an alternativ? Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Notify me of follow-up comments by email.H2 database is a pure Java, open source and very fast engine. We can use H2 for development, testing and performance benchmarking.
H2 database has small footprint smaller than 1. We can use H2 with disk based or in-memory databases. H2 can be built by following mode: — Embedded mode local connections — Server mode remote connections — Mixed mode local and remote connections.
How to configure it with SpringBoot? H2 supports a convenient web based data console to interact with database while the development:. Set spring. Driver — datasource. Annotation Entity indicates that Customer is an Entity and Table specifies the primary table name customer for the annotated Entity. ID specifies the primary key and GeneratedValue indicates generation strategy for value of primary key. In the web controller methods which are annotated by RequestMappingwe have used some methods of autowired repository which are implemented interface CrudRepository :.
Build and Run the SpringBoot with commandlines: mvn clean install and mvn spring-boot:run. Then press Connectand makes a first select for customer table:. Now, do restart the SpringBoot App, then select customer table again:. Please advisewhether there is a step to create the table. Spring Boot chooses a default value for you based on whether it thinks your database is embedded: spring.
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Integrate an H2 Database in Your Spring Boot App
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It is mandatory to procure user consent prior to running these cookies on your website. Skip to content. Contents I. H2 database and SpringBoot integration II. Practice 1. Create SpringBoot project 2.
Configure H2 database 3. Serializable .In this tutorial, we will create a Spring Boot application which demonstrates how we can add and use the H2 in-memory database in our application. You will learn how an in-memory database like H2 can be used to develop a Spring boot application without an overhead of doing DB configuration on your machine and without specifying any config details in the app. H2 database is an open source database written in Java programming language which supports querying data in standard SQL.
It is very much lightweight and its JAR file is only 1. Although H2 is an in-memory database which means that data will be wiped out of the memory as soon as the application is stopped. H2 is pretty fast database and can be used for many purposes like:. For use-cases like the above, in-memory databases are quite evident in usage due to their quick setup and minimal configuration needed at the application side.
In this lesson, we will see what we can do with an in-memory database when it is integrated with a Spring Boot application. To quickly set up our project, we will use a tool called Spring Initializr. Using this tool, we can quickly provide a list of Dependencies we need and download the bootstrapped application:.
Spring BootでH2 データベースを設定、利用する｜H2 DataBase
When creating a new project with the Spring Initializr, we used the following dependencies:. Though this tool helps us to add the above dependencies, below is a source code of pom. Use any IDE to open the downloaded Maven based project. To implement our project with Spring Boot and to use H2 as our in-memory database, we will make use of Maven to manage dependencies.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have successfully created a spring boot application that uses the H2 embedded database in-memory. I would now like to change this to a file based version that will persist. I have tried just changing the spring. My understanding from the documentation and a number of posts is that the configuration should just work but no luck for me.
Just to prevent some of the basic errors I have tried and checked the following:. What is interesting here is that my config has been taken and the database exists but when the application runs it does not use this dataSource. Actually I have the same problem and none of the answer worked for me completely rather than the mix for some answers worked.
Using the following setting on application. Just generated a brand new Spring Boot project with start. After adding a simple Entity and Spring Data repository, the database is indeed created in memory by default. Adding the following to my application. Create a file. You can create this file in resources folder. Learn more. How to configure spring-boot to use file based H2 database Ask Question. Asked 3 years, 9 months ago.
Active 8 months ago. Viewed 67k times. This causes other errors related to the type being null. Seems like I am missing a key concept or something. Can anyone help. Michael Lihs 4, 7 7 gold badges 32 32 silver badges 57 57 bronze badges. Active Oldest Votes. Issue is that the application is not using it. Adding the spring-boot-starter-jdbc to the pom.
Thank you. Would be great to know why this fixed it. I am adding this answer to avoid confusion and further research.Learn to configure H2 database with Spring boot to create and use an in-memory database in runtime, generally for unit testing or POC purposes.
H2 is one of the popular in-memory databases written in Java. It can be embedded in Java applications or run in the client-server mode. Spring Boot provides excellent integration support for H2 using simple properties configuration. To make it even more useful, H2 also provides a console view to maintain and interact with the database tables and data.
To use H2 in Spring boot application, all we need to do is adding H2 runtime jar into dependencies. The best way to add is through maven. Spring provides very easy configuration options to connect to any database using simple properties.
Below are the configuration properties, we shall have in application. Please note by default, Spring Boot configures the in-memory database connection with the username 'sa' and an empty password ' '.
If you wish to change these values, override them in above properties options. The in-memory databases are volatile, by default, and all stored data will be lost when we restart the application.
In this case, data is written in temporary memory and as soon as JVM is stopped, data is flushed. For this change the spring.
We may want to initialize database with some fixed schema DDL and insert default data DML into tables before the application is ready is run business usecases. By default, the console view of H2 database is disabled. We must enable it to view and access it in browser. Now enter the configured username and password. We can verify the table structure and default data inserted through SQL files. Spring boot provides two more properties to further customize the behavior of H2 console.
In this Spring boot with H2 database tutorialwe learned to configure, initialize and access H2 database through an spring boot application using simple properties configuration options. A family guy with fun loving nature.When I talk about some of the mybatis features, I always write some examples to show to my fans. Of course, you can also use docker to install. But we still need to rely on something.
Is there a very small and portable database that can meet the needs of very small scenes. Of course. These are just the features listed on the official website. In fact, it has the advantage of cross platform, supporting most of the common platforms at present.
Based on the above characteristics. H2 database is especially suitable for small-scale applications that are built quickly. Especially in application development and unit testing, it is very convenient to use, and it saves system resources.
And the dependency pool of springboot also contains the H2 database. Next, we use spring boot and mybatis to explain and demonstrate some features of H2 database. Spring boot is very easy to use H2 database. Just integrate the H2 dependency under BOM. We also introduced mybatis for demonstration. Of course, the introduction of dependency is not enough. We need to configure other parameters. Of course, these configurations can be completed through application.
Using H2 In-memory Database with Spring Boot
Properties of springboot. We know that H2 supports embedded spring boot applications like tomcat, and also supports independent server process mode. The embedded mode is to introduce H2 into the application, start the application, and start the H2 data service.
The application includes both the server of H2 database and the application as the client to connect H2 database. The memory mode is that the database files exist in memory without persistence. When the application process is closed, the database and data table will disappear. In order to separate the environment, we use the profile feature of springboot to isolate the environment configuration of different modes.
We customized an application-inner. The configuration is as follows:. After the springboot project is started by specifying — spring. Be sure to set the red box according to the spring. Do not use the default value. If the password is not set, click connect directly, and the password is set.You can run Oracle on a laptop.
You may be used to dealing with a legacy code base, in which you dependent on an Oracle database. This will allow your application to run locally from your laptop using an in memory H2 database, and then against an Oracle database. The active profile will control which data source is selected by Spring to configure and use for dependency injection. For a long time relational databases supported a auto-increment data type, which is often used for the primary key.
Until Oracle 12c, this feature was not supported. For the identity mapping in your JPA domain classes you need to use a sequence generator. This means a database sequence will be used to get the next primary key value when creating new entities.
In this example, we will be configuring our JPA mapping to use a database sequence for database identity. This means both data sources need to support the use of a database sequence.
In Oracle 12c, auto increment was added as a new feature. This looks like it is supported by Hibernate 5, however, at the time of writing I could not get this feature working. It looked like a potential bug in Hibernate. By default, Spring Boot will configure an H2 database for us. H2 is a great database to develop against because it has an Oracle compatibility mode. More and more often developers will have restricted access to Oracle in development, QA, and production.
Thus, often your database account will not be able to create or modify database tables. To do this, we will need to override the default Spring Boot property. The Spring Framework has an awesome feature introduced in the Spring 3.
Through the use of Profiles you can define multiple Spring Beans for the same type, but control which Spring Bean Spring will create for you based on which of the profiles are active. This is a very powerful feature of Spring which allows you to compose your application for different environments. Spring Boot also will by default load properties files for specific active profiles. The default properties file is also loaded.Spring Boot H2 Database Console
Thus when setting up your properties files of Spring Boot, you can place all the common properties in the default properties file application. Spring Boot has the ability to run custom SQL scripts on startup. The H2 database is going to be created in memory each time our Spring Boot app starts up, thus we want to run our DDL statements on startup only when the H2 profile is active.
Which effectively overwrites our customizations, and is a behavior we do not want. Our approach to configure this is very similar setting up the properties files. Spring Boot will execute any SQL script named schema. For our use case, we only want this script to run for the H2 database. In this case, we can use the data source platform setting. Key point is to remember this is different from Spring Profiles.
Thus Hibernate will only need to read the sequence once every inserts. This will significantly improve performance on an application with heavy inserts. Increasing the cache of the database sequence will also have a large impact on insert performance. However, I want to override the default increment and cache settings, hence the need for the schema SQL script. The syntax is the same for Oracle.
From my previous example, we need to update the Product class to use the database sequence for the primary key generation.