Question

我使用JPA而没有Spring连接到具有不同结构的多个postgreSql数据库。我的persistence.xml：

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" 
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         version="2.0">
<persistence-unit name="central" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
  <!--   <provider>org.hibernate.ejb.HibernatePersistence</provider> -->
    <class>model.central.Invoice</class>
   <!--  <exclude-unlisted-classes>false</exclude-unlisted-classes>-->

    <properties>
        <property name="hibernate.connection.url" value="jdbc:postgresql://xxx.xx.xxx.xx:5432/central"/>
        <property name="hibernate.connection.driver_class" value="org.postgresql.Driver"/>
        <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
        <property name="hibernate.connection.username" value="admin"/>
        <property name="hibernate.connection.password" value="xxxx"/>
        <property name="hibernate.show_sql"     value="false"/>
        <property name="hibernate.format_sql"   value="true"/>
        <property name="hibernate.flushMode"    value="FLUSH_AUTO"/>
        <!-- <property name="hibernate.hbm2ddl.auto" value="validate"/> -->
        <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
        <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
    </properties>
</persistence-unit>

<persistence-unit name="S1A" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
  <!--   <provider>org.hibernate.ejb.HibernatePersistence</provider> -->
    <class>model.customer</class>
    <!--  <exclude-unlisted-classes>false</exclude-unlisted-classes>-->

    <properties>
        <property name="hibernate.connection.url" value="jdbc:postgresql://xxx.xx.xx.xx:5432/S1A"/>
        <property name="hibernate.connection.driver_class" value="org.postgresql.Driver"/>
        <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
        <property name="hibernate.connection.username" value="admin"/>
        <property name="hibernate.connection.password" value="xxxx"/>
        <property name="hibernate.show_sql"     value="false"/>
        <property name="hibernate.format_sql"   value="true"/>
        <property name="hibernate.flushMode"    value="FLUSH_AUTO"/>
        <!-- <property name="hibernate.hbm2ddl.auto" value="validate"/> -->
        <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
        <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
    </properties>
</persistence-unit>

出于某种原因，当我坚持我的客户模型对象时，我也看到在两个数据库上都创建了Invoice表。当我坚持使用这些对象时，我期待在我的“中心”数据库和我的“S1A”数据库中的Customer表中看到Invoice表。但是，当我持久化一个对象时，两个数据库都以Customer和Invoice表结束。

这是我的DAO课程：

public class Dao {

private String dbname;
private static Map<String, EntityManager> emMap;

private static EntityManagerFactory entityManagerFactoryCentral;
private static EntityManager entityManagerCentral;

private static EntityManagerFactory entityManagerFactoryS1A;
private static EntityManager entityManagerS1A;

static {


    emMap = new HashMap<String, EntityManager>();
    entityManagerFactoryCentral =         Persistence.createEntityManagerFactory("central");
    entityManagerCentral = entityManagerFactoryCentral.createEntityManager();   
    emMap.put("central", entityManagerCentral);


    entityManagerFactoryS1A = Persistence.createEntityManagerFactory("S1A");
    entityManagerS1A = entityManagerFactoryS1A.createEntityManager();   
    emMap.put("S1A", entityManagerS1A);
}

public Dao(String dbname) { 
    this.dbname = dbname;
}
public void persist( Object... objects ){

    EntityManager entityManager = emMap.get(dbname);
    try {
        entityManager.getTransaction().begin();

        for ( Object object : objects ){
            entityManager.persist(object);
        }
        entityManager.getTransaction().commit();

    } catch( Exception e ){
        e.printStackTrace();
        try {
            entityManager.getTransaction().rollback();

         } catch (Exception e2){
            e2.printStackTrace();
        }
     }
}

所以，这里的问题是如何在没有Spring的情况下使用一个persistence.xml文件，并使用JPA连接到model.central和model包下不同类列表的多个数据库。

Answer 1

对不起这篇文章。我正在编辑驻留在war / META-INF下的错误的persistent.xml文件，而不是类路径src / META-INF。另外，我必须将true添加到持久性单元。

没有Spring的多个数据库的JPA持久性配置

1 个答案: