[JAVA] Until the use of Spring Data and JPA Part 2

The difficulty of setting is quite high.

Continued from last time

For the time being, I used Spring to connect to the DB. From here, we will use a full-fledged DB operation framework called JPA.

Divide goals

1. 1. What you need just to connect with SQL -Hibernate EntityManager library ・ Spring JDBC library ・ Database driver PostgreSQL or H2 ·Property file -Bean configuration file (xml) JavaConfig is not used this time. Maybe it's going to get confusing ** ← So far **

2. In addition, what is required for JPA ** ← From here ** ・ Spring Data JPA library ・ Entity class -Persistence.xml file (Java EJB function) -Bean configuration file (xml) -Execution class with main method

Add library

Add library as usual. When you use new features in Spring, you usually edit the library.

pom.xml

		<!-- Spring Data JPA -->
		<dependency>
			<groupId>org.springframework.data</groupId>
			<artifactId>spring-data-jpa</artifactId>
		</dependency>
		
		<!-- Spring ORM -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>

After saving ** Maven → update Project **

Entity class

Click here for how to create an entity class from a table. wrap up Right click and convert from configuration to JPA project. When it becomes a JPA project, an entity will be automatically generated from the table.

https://qiita.com/shibafu/items/39f3f5d6e63dda16bb12

It's really hard to see,

When the Entity is created, add an annotation such as @Id and pick up the error. You may want to use ** lombok ** and omit the getter setter in @Data

Auto-implemented entity class

Creating persistence.xml

Create a META-INF folder in src / main / resources and a persistance.xml file in it. It seems to be a Java-EE function called ** persistence file ** (If you created it with JPA, it is created in src / main / java, so move it)

Sketch src/main/resources/ 　　| 　　|---META-INF 　　|　　　　| 　　| 　　　|--persistance.xml 　　|---bean.xml 　　|---database.properties

persitance.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
   xmlns="http://xmlns.jcp.org/xml/ns/persistence"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
		http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
   
	<persistence-unit name="persistance-unit">
		
		<!--HibernatePersistance definition-->
		<provider>org.hibernate.ejb.HibernatePersistence</provider>
		<class>model.Mypersonaldata</class>
		
		<properties>
			<property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect"/>
			
			<property name="hibernate.hbm2ddl.auto" value="create" />
			
				<!--Driver properties-->
				<property name="javax.persistance.jdbc.driver"
					value="${jdbc.driverClassname}" />
				<property name="javax.persistance.jdbc.url"
					value="${jdbc.url}" />
				<property name="javax.persistance.jdbc.user"
					value="${jdbc.username}" />
				<property name="javax.persistance.jdbc.password"
					value="${jdbc.password}" />	
		</properties>
	</persistence-unit>
</persistence>

Creating a bean configuration file

Finally, create a bean configuration file. Namespace xmlns = http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/spring-jpa.xsd Add Register the entity manager with the DI container.

bean.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:jdbc="http://www.springframework.org/schema/jdbc"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	 http://www.springframework.org/schema/beans/spring-beans.xsd
	 http://www.springframework.org/schema/data/jpa
	 http://www.springframework.org/schema/data/spring-jpa.xsd
	 http://www.springframework.org/schema/context
	 http://www.springframework.org/schema/context/spring-context.xsd
	 http://www.springframework.org/schema/jdbc
	 http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
	 http://www.springframework.org/schema/tx
	 http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">


	<!--Settings for embedded database>
	<jdbc:embedded-database id="dataSource" type="H2">
		<jdbc:script location="classpath:script.sql"/>
	</jdbc:embedded-database-->

	<!--Setting database properties-->
	<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
	  	<property name="location" value="database.properties" />
	</bean>

	<!--EntityManager settings-->
	<bean id="entityManagerFactory"
		class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
		<property name="dataSource" ref="dataSource" />
		<property name="jpaVendorAdapter">
			<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
				<property name="generateDdl" value="true" />
			</bean>
		</property>
	</bean>

	<!--Settings for DB connection-->
	<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource" >
		<property name="driverClassName" value="${jdbc.driverClassName}" />
		<property name="url" value="${jdbc.url}" />
		<property name="username" value="${jdbc.username}" />
		<property name="password" value="${jdbc.password}" />
	</bean>

	<!--Creating a JDBC template bean-->
	<bean class="org.springframework.jdbc.core.JdbcTemplate">
		<constructor-arg ref="dataSource" />
	</bean>

	
		<!--JPA Repository settings-->
	<jpa:repositories base-package="com.TsugaruInfo.repository" />
	
     <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
        <property name="dataSource" ref="dataSource" />
    </bean>
</beans>

Let's run

Let's put the entity manager in the main class and perform JPA functions!

App.java

public class App{
	public static void main(String args[]) {
		
		//Creating a template using annotations
		//context = new AnnotationConfigApplicationContext(DataSourceConfig.class);
		//JdbcTemplate jdbcTemplate = (JdbcTemplate)context.getBean(JdbcTemplate.class);
		//Get context
//		context = new ClassPathXmlApplicationContext("bean.xml");
//		jdbcTemplate = context.getBean(JdbcTemplate.class);
	
		context = new ClassPathXmlApplicationContext("bean.xml");
		
		LocalContainerEntityManagerFactoryBean factory =
				context.getBean(LocalContainerEntityManagerFactoryBean.class);
		manager = factory.getNativeEntityManagerFactory().createEntityManager();
		
		Mypersonaldata data = manager.find(Mypersonaldata.class, 1);
		
			System.out.println(data);
	
	}
}

Run this from Java Application

At the bottom, you can see the data read from postgresql.

Summary.

Well, with Spring-Boot, this procedure is all done automatically, I couldn't keep the basics down and it stopped working, so for reference.