Spring、JPA、および Hibernate を使用しています。これは、より大きな JPA 関連の問題をデバッグするために使用しているおもちゃの例です。ただし、非常に基本的なエンティティを永続化しようとするこの単純な例では、HelloBean切り離されたオブジェクトが作成されているようです。私が知る限りpersist、EntityManagerオブジェクトを呼び出すと、エンティティが永続コンテキストによって管理されるように設定する必要があります。ただし、これは機能しませんmerge。出力は次のとおりです。
Starting...
Service found in context as: net.solasistim.hello.HelloService@3b7a687b
Hibernate: insert into HelloBean (message) values (?)
Is bean attached? = false
Hibernate: select hellobean0_.id as id1_0_0_, hellobean0_.message as message2_0_0_ from HelloBean hellobean0_ where hellobean0_.id=?
Is bean attached? = false
簡潔にするためにインポートは省略されています。
Hello.java::
public class Hello {
public static void main(String[] args) throws Exception {
ApplicationContext context =
new ClassPathXmlApplicationContext("beans.xml");
System.out.println("Starting...");
HelloService svc = (HelloService) context.getBean("helloService");
System.out.println("Service found in context as: " + svc);
HelloBean bean1 = new HelloBean();
bean1.setMessage("This is bean 1.");
HelloBean bean2 = new HelloBean();
bean2.setMessage("This is bean 2.");
svc.persist(bean2);
System.out.println("Is bean attached? = " + svc.isAttached(bean2));
HelloBean newBean = svc.merge(bean2);
System.out.println("Is bean attached? = " + svc.isAttached(newBean));
}
}
HelloService.java::
@Service
@Transactional
public class HelloService {
@PersistenceContext private EntityManager em;
public void persist(HelloBean entity) {
em.persist(entity);
}
public HelloBean merge(HelloBean entity) {
return em.merge(entity);
}
public void delete(HelloBean entity) {
em.remove(entity);
}
public boolean isAttached(HelloBean entity) {
return em.contains(entity);
}
}
HelloBean.java::
@Entity
public class HelloBean {
@Id
@GeneratedValue
private long id;
private String message;
public void setMessage(String message) {
this.message = message;
}
public String getMessage() {
return this.message;
}
}
pom.xml::
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>net.solasistim.hello</groupId>
<artifactId>hello</artifactId>
<version>1</version>
<packaging>jar</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.2.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>3.2.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.2.0.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.2.0.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.24</version>
</dependency>
</dependencies>
</project>
beans.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:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<context:component-scan base-package="net.solasistim.hello"/>
<context:annotation-config />
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitName" value="my-persistence-unit"/>
</bean>
<!-- These two are needed for @Transactional annotations to be processed.
Nothing will be committed without them. -->
<tx:annotation-driven/>
<bean id="transactionManager"
class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
</beans>
persistence.xml::
<?xml version="1.0"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="my-persistence-unit">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.dialect"
value="org.hibernate.dialect.MySQLDialect" />
<property name="hibernate.connection.driver_class"
value="com.mysql.jdbc.Driver" />
<property name="hibernate.connection.url"
value="jdbc:mysql://localhost:3306/jpa_test" />
<property name="hibernate.connection.username"
value="root" />
<property name="hibernate.connection.password"
value="" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.hbm2ddl.auto" value="create" />
</properties>
</persistence-unit>
</persistence>