I have two databases that I connect to in my application.
I want to set up a dev-only profile that mocks these databases using an embedded H2 database, and I would like to have their schemas auto-created by using spring.jpa.generate-ddl=true. The entity classes for each database are in different java packages, which I hope might help me here.
Is such a thing possible using spring's autoconf mechanisms?
It is possible to use multiple databases in spring boot.
But spring boot can automatically configure only one database.
You need to configure the second database yourself.
#Bean
#ConfigurationProperties(prefix="second.datasource")
public DataSource secondDataSource(){
return DataSourceBuilder
.create()
.driverClassName("org.h2.Driver")
.build();
}
If you just need a jdbc connection, this would be already sufficient. As you want to use JPA you need also a second JPA configuration, that uses the second data source.
#Bean(name="secondEntityManager")
public LocalContainerEntityManagerFactoryBean mySqlEntityManagerFactory(EntityManagerFactoryBuilder builder,DataSource secondDataSource){
return builder.dataSource(secondDataSource)
.packages("com.second.entity")
.build();
}
You can find the code above and more in this post
Related
I would like to share all my project Repository interfaces with different database implementation (PostgreSQL, MySQL, ...), but having also some specific Repository with native query, for every db platform.
How can I achieve it? Is it possible to annotate a Repository to be used only with a specific database?
if you can not do it with annotations you could find out the dialect of the database and act accordingly.
an example
private boolean isOracle() {
Session session = (Session) entityManager.getDelegate();
Dialect dialect = ((SessionFactoryImpl) session.getSessionFactory()).getJdbcServices().getDialect();
return dialect.getClass().getName().contains("Oracle");
}
so if (isOracle()) you would use your oracleJpaNativeRepository
I got to know Java spring JPA a couple days ago and there is one question which really makes me confused.
As I create a repository and use 'save()' method to save some objects into it. How does it know what type of database I am using and which local location to save.
I know I can config database (h2) like:
spring.datasource.url=jdbc:h2:mem/mydb
Then JPA will know: ok you are using h2 database and url is "jdbc:h2:mem/mydb"
However, some people said this config is not mandatory. If without this config, how does JPA knows which database I gonna use?
From the spring-boot documentation:
You should at least specify the URL by setting the spring.datasource.url property. Otherwise, Spring Boot tries to auto-configure an embedded database.
The following class is responsible for providing default settings for embedded DB: org.springframework.boot.autoconfigure.jdbc.DataSourceProperties
public String determineDatabaseName() {
...
if (this.embeddedDatabaseConnection != EmbeddedDatabaseConnection.NONE) {
return "testdb";
}
...
}
This answer can also be helpful: Where does the default datasource url for h2 come from on Spring Boot?
I am working on a project that has a requirement of Pivotal GemFire.
I am unable to find a proper tutorial about how to configure gemFire with Spring Boot.
I have created a partitioned Region and I want to configure Locators as well, but I need only server-side configuration as client is handled by someone else.
I am totally new to Pivotal GemFire and really confused. I have tried creating a cache.xml but then somehow a cache.out.xml gets created and there are many issues.
#Priyanka-
Best place to start is with the Guides on spring.io. Specifically, have a look at...
"Accessing Data with GemFire"
There is also...
"Cache Data with GemFire", and...
"Accessing GemFire Data with REST"
However, these guides focus mostly on "client-side" application concerns, "data access" (over REST), "caching", etc.
Still, you can use Spring Data GemFire (in a Spring Boot application even) to configure a GemFire Server. I have many examples of this. One in particular...
"Spring Boot GemFire Server Example"
This example demonstrates how to bootstrap a Spring Boot application as a GemFire Server (technically, a peer node in the cluster). Additionally, the GemFire properties are specified Spring config and can use Spring's normal conventions (property placeholders, SpEL expression) to configure these properties, like so...
https://github.com/jxblum/spring-boot-gemfire-server-example/blob/master/src/main/java/org/example/SpringBootGemFireServer.java#L59-L84
This particular configuration makes the GemFire Server a "GemFire Manager", possibly with an embedded "Locator" (indicated by the start-locator GemFie property, not to be confused with the "locators" GemFire property which allows our node to join and "existing" cluster) as well as a GemFire CacheServer to serve GemFire cache clients (with a ClientCache).
This example creates a "Factorials" Region, with a CacheLoader (definition here) to populate the "Factorials" Region on cache misses.
Since this example starts an embedded GemFire Manager in the Spring Boot GemFire Server application process, you can even connect to it using Gfsh, like so...
gfsh> connect --jmx-manager=localhost[1099]
Then you can run "gets" on the "Factorial" Region to see it compute factorials of the numeric keys you give it.
To see more advanced configuration, have a look at my other repos, in particular the Contacts Application RI (here).
Hope this helps!
-John
Well, I had the same problem, let me share with you what worked for me, in this case I'm using Spring Boot and Pivotal GemFire as cache client.
Install and run GemFire
Read the 15 minutes quick start guide
Create a locator(let's call it locator1) and a server(server1) and a region(region1)
Go to the folder where you started the 'Gee Fish'(gfsh) and then go to the locator's folder and open the log file, in that file you can get the port your locator is using.
Now let's see the Spring boot side:
In you Application with the main method add the #EnablegemFireCaching annotation
In the method(wherever it is) you want to cache, add the #Cacheable("region1") annotation.
Now let's create a configuration file for the caching:
//this is my working class
#Configuration
public class CacheConfiguration {
#Bean
ClientCacheFactoryBean gemfireCacheClient() {
return new ClientCacheFactoryBean();
}
#Bean(name = GemfireConstants.DEFAULT_GEMFIRE_POOL_NAME)
PoolFactoryBean gemfirePool() {
PoolFactoryBean gemfirePool = new PoolFactoryBean();
gemfirePool.addLocators(Collections.singletonList(new ConnectionEndpoint("localhost", HERE_GOES_THE_PORT_NUMBER_FROM_STEP_4)));
gemfirePool.setName(GemfireConstants.DEFAULT_GEMFIRE_POOL_NAME);
gemfirePool.setKeepAlive(false);
gemfirePool.setPingInterval(TimeUnit.SECONDS.toMillis(5));
gemfirePool.setRetryAttempts(1);
gemfirePool.setSubscriptionEnabled(true);
gemfirePool.setThreadLocalConnections(false);
return gemfirePool;
}
#Bean
ClientRegionFactoryBean<Long, Long> getRegion(ClientCache gemfireCache, Pool gemfirePool) {
ClientRegionFactoryBean<Long, Long> region = new ClientRegionFactoryBean<>();
region.setName("region1");
region.setLookupEnabled(true);
region.setCache(gemfireCache);
region.setPool(gemfirePool);
region.setShortcut(ClientRegionShortcut.PROXY);
return region;
}
That's all!, also do not forget to serialize(implements Serializable) the class is being cached(The class your cached method is returning)
I am trying to use flyway for DB migrations and Spring boot's flyway support for auto-upgrading DB upon application start-up and subsequently this database will be used by my JPA layer
However this requires that schema be present in the DB so that primary datasource initialization is successful. What are the options available to run a SQL script that will create the required schema before flyway migrations happen.
Note that If I use flyway gradle plugin (and give the URL as jdbc:mysql://localhost/mysql. It does create the schema for me. Am wondering if I could make this happen from Java code on application startup.
Flyway does not support full installation when schema is empty, just migration-by-migration execution.
You could though add schema/user creation scripts in the first migration, though then your migration scripts need to be executed with sysdba/root/admin user and you need to set current schema at the beginning of each migration.
If using Flyway, the least problematic way is to install schema for the first time manually and do a baseline Flyway task (also manually). Then you are ready for next migrations to be done automatically.
Although Flyway is a great tool for database migrations it does not cover this particular use case well (installing schema for the first time).
"Am wondering if I could make this happen from Java code on application startup."
The simple answer is yes as Flyway supports programmatic configuration from with java applications. The starting point in the flyway documentation can be found here
https://flywaydb.org/documentation/api/
flyway works with a standard JDBC DataSource and so you can code the database creation process in Java and then have flyway handle the schema management. In many environment you are likely to require 2 steps anyway as the database/schema creation will need admin rights to the database, while the ongoing schema management will need an account with reduced access rights.
what you need is to implement the interface FlywayCallback
in order to kick start the migration manually from you code you can use the migrate() method on the flyway class
tracking the migration process can be done through the MigrationInfoService() method of the flyway class
Unfortunately if your app has a single datasource that expects the schema to exist, Flyway will not be able to use that datasource to create the scheme. You must create another datasource that is not bound to the schema and use the unbounded datasource by way of a FlywayMigrationStrategy.
In your properties file:
spring:
datasource:
url: jdbc:mysql://localhost:3306/myschema
bootstrapDatasource:
url: jdbc:mysql://localhost:3306
In your config file:
#Bean
#Primary
#ConfigurationProperties("spring.datasource")
public DataSourceProperties primaryDataSourceProperties() {
return new DataSourceProperties();
}
#Bean
#Primary
#ConfigurationProperties("spring.datasource")
public DataSource primaryDataSource() {
return primaryDataSourceProperties().initializeDataSourceBuilder().build();
}
#Bean
#ConfigurationProperties("spring.bootstrapDatasource")
public DataSource bootstrapDataSource() {
return DataSourceBuilder.create().build();
}
And in your FlywayMigrationStrategy file:
#Inject
#Qualifier("bootstrapDataSource")
public void setBootstrapDataSource(DataSource bootstrapDataSource) {
this.bootstrapDataSource = bootstrapDataSource;
}
#Override
public void migrate(Flyway flyway) {
flyway.setDataSource(bootstrapDataSource);
...
flyway.migrate()
}
I'm aware that H2 has a boolean property/setting called DATABASE_TO_UPPER, which you can set at least in the connection URL, as in: ;DATABASE_TO_UPPER=false
I’d like to set this to false, but in my Spring Boot app, I don’t explicitly have a H2 connection URL anywhere. Implicitly there sure is a connection URL though, as I can see in the logs:
o.s.j.d.e.EmbeddedDatabaseFactory: Shutting down embedded database:
url='jdbc:h2:mem:2fb4805b-f927-49b3-a786-2a2cac440f44;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false'
So the question is, what's the easiest way to tell H2 to disable DATABASE_TO_UPPER in this scenario? Can I do it in code when creating the H2 datasource with EmbeddedDatabaseBuilder (see below)? Or in application properties maybe?
This is how the H2 database is explicitly initialised in code:
#Configuration
#EnableTransactionManagement
public class DataSourceConfig {
#Bean
public DataSource devDataSource() {
return new EmbeddedDatabaseBuilder()
.generateUniqueName(true)
.setType(EmbeddedDatabaseType.H2)
.setScriptEncoding("UTF-8")
.ignoreFailedDrops(true)
.addScripts("db/init.sql", "db/schema.sql", "db/test_data.sql")
.build();
}
}
Also, I'm telling JPA/Hibernate not to auto-generate embedded database (without this there was an issue that two in-memory databases were launched):
spring.jpa.generate-ddl=false
spring.jpa.hibernate.ddl-auto=none
You can't w\ the generateUniqueName, but if you call setName("testdb;DATABASE_TO_UPPER=false") you can add parameters. I doubt this is officially supported, but it worked for me.
The spring code that generates the connection url is like this:
String.format("jdbc:h2:mem:%s;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false", databaseName)
You may want abandon using explicit creation via EmbeddedDatabaseBuilder. Spring Boot creates H2 instance automatically based on configuration. So I would try this in application.properties:
spring.datasource.url=jdbc:h2:file:~/testdb;DATABASE_TO_UPPER=false