Question

我是Java EE和JPA的新手。所以我写了下面的测试代码。我的问题是，那个数据库表＆＃34; Blue＆＃34;已创建，但jpa实体不在eclipselink-orm.xml中。通常在创建动态实体时，这些实体存储在xml而不是pojo类中是否正确？以下代码中的错误是什么？：

Main.class：

public class Main {

    public static void main(String[] args) {
        createTestEntities();
    }

    public static EntityManagerFactory getEmf() {

        HashMap<String, String> connectionProperties;
        connectionProperties = new HashMap<String, String>();
        connectionProperties.put("eclipselink.jdbc.password", "root");
        connectionProperties.put("eclipselink.jdbc.user", "root");
        connectionProperties.put("eclipselink.jdbc.driver", "com.mysql.jdbc.Driver");
        connectionProperties.put("eclipselink.jdbc.url", "jdbc:mysql://localhost:3306/test");
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("Test", connectionProperties);
        return emf;
    }

    public static void createTestEntities() {
        EntityManagerFactory emf = getEmf();
        EntityManager em = emf.createEntityManager();

        try {
        Session session = JpaHelper.getEntityManager(em).getServerSession();
        DynamicClassLoader dcl = DynamicClassLoader.lookup(session);

        String tableName = "BLUE";
        String objectName = "blue";

        Class<?> clazz = dcl.createDynamicClass("com.example." + objectName);

        DynamicTypeBuilder builder = null;

        builder = new JPADynamicTypeBuilder(clazz, null, tableName);
        // Die Attribute werden im Key-Value-Style gesetzt
        builder.addDirectMapping("ID", Long.class, "MyID");
        builder.addDirectMapping("STRING", String.class, "name");
        builder.setPrimaryKeyFields("MyID");

        DynamicType type = builder.getType();
        DynamicHelper dynamicHelper = new JPADynamicHelper(em);
        dynamicHelper.addTypes(true /* create table */, false /*foreign key constraints*/, type);
        }
        catch(DynamicException e) {

        } catch(PersistenceException e) {

        } catch(Exception e) {

        }
    }

}

的persistence.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="Test">
        <mapping-file>META-INF/eclipselink-orm.xml</mapping-file>

        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/test" />
            <property name="javax.persistence.jdbc.user" value="root" />
            <property name="javax.persistence.jdbc.password" value="root" />


            <!-- EclipseLink should create the database schema automatically -->
            <property name="eclipselink.ddl-generation" value="create-tables" />
            <property name="eclipselink.ddl-generation.output-mode"
                value="database" />
        </properties>
    </persistence-unit>
</persistence>

的EclipseLink-orm.xml中：

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings version="2.1"
    xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/orm"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <package>com.example</package>

    <persistence-unit-metadata>
        <xml-mapping-metadata-complete />
        <exclude-default-mappings />
        <persistence-unit-defaults>
            <access>VIRTUAL</access>
            <access-methods set-method="get" get-method="set" />
        </persistence-unit-defaults>
    </persistence-unit-metadata>

</entity-mappings>

JPA Eclipselink动态实体不在eclipselink-orm.xml中

0 个答案: