5.9. JPA
JPA 集成由 Camel JPA 组件提供。您可以通过提供 persistence.xml 配置文件以及一些 JPA 注解的类来开发 Camel JPA 应用程序。
5.9.1. persistence.xml 示例
在以下示例中,您可以使用 JBoss EAP in-memory ExampleDS 数据源,该数据源在 JBoss EAP standalone.xml 配置文件中配置。
<persistence version="2.0"
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">
<persistence-unit name="camel">
<jta-data-source>java:jboss/datasources/ExampleDS</jta-data-source>
<class>org.wildfly.camel.test.jpa.model.Customer</class>
<properties>
<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
<property name="hibernate.show_sql" value="true"/>
</properties>
</persistence-unit>
</persistence>5.9.2. JPA ENTitiy 示例
@Entity
@Table(name = "customer")
public class Customer implements Serializable {
@Id
@GeneratedValue
private Long id;
private String firstName;
private String lastName;
public Customer() {
}
public Customer(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
public Long getId() {
return id;
}
public void setId(final Long id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}5.9.3. Camel JPA endpoint / route configuration
配置 JPA 后,您可以使用 CDI 将 EntityManager 和 UserTransaction 实例注入 RouteBuilder 类或测试案例中:
@PersistenceContext EntityManager em; @Inject UserTransaction userTransaction;
现在,配置 Camel 路由和 JPA 端点:
WildFlyCamelContext camelctx = contextFactory.createCamelContext(getClass().getClassLoader());
EntityManagerFactory entityManagerFactory = em.getEntityManagerFactory();
// Configure a transaction manager
JtaTransactionManager transactionManager = new JtaTransactionManager();
transactionManager.setUserTransaction(userTransaction);
transactionManager.afterPropertiesSet();
// Configure the JPA endpoint to use the correct EntityManagerFactory and JtaTransactionManager
final JpaEndpoint jpaEndpoint = new JpaEndpoint();
jpaEndpoint.setCamelContext(camelctx);
jpaEndpoint.setEntityType(Customer.class);
jpaEndpoint.setEntityManagerFactory(entityManagerFactory);
jpaEndpoint.setTransactionManager(transactionManager);
camelctx.addRoutes(new RouteBuilder() {
@Override
public void configure() throws Exception {
from("direct:start")
.to(jpaEndpoint);
}
});
camelctx.start();最后,您可以将 'Customer' 实体发送到 'direct:start' 端点,然后查询 ExampleDS 数据源来验证已保存记录。
Customer customer = new Customer("John", "Doe");
ProducerTemplate producer = camelctx.createProducerTemplate();
producer.sendBody("direct:start", customer);
// Query the in memory database customer table to verify that a record was saved
CriteriaBuilder criteriaBuilder = em.getCriteriaBuilder();
CriteriaQuery<Long> query = criteriaBuilder.createQuery(Long.class);
query.select(criteriaBuilder.count(query.from(Customer.class)));
long recordCount = em.createQuery(query).getSingleResult();
Assert.assertEquals(1L, recordCount);