我为Hibernate / JPA配置问题感到困惑,该问题阻止了我的带有JPA注释的实体自动注册:
java.lang.IllegalArgumentException: Unknown entity: com.example.crm.server.model.Language at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:671) at com.example.crm.server.model.Language.persist(Language.java:64) at com.example.crm.server.LanguageTest.testPersistAndRemove(LanguageTest.java:32) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
在我的实体课程中,我有:
@Entity @Table(name="Languages") public class Language implements Serializable { @Id private Long id; private String name; // etc... }
在MySQL中,语言表如下所示:
+-------------+----------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------------+----------+------+-----+---------+-------+ | Language_ID | int(11) | NO | PRI | NULL | | | Name | char(18) | YES | | NULL | | +-------------+----------+------+-----+---------+-------+ 2 rows in set (0.00 sec)
我的persistence.xml看起来像:
<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="crm"> <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/crm"/> <property name="hibernate.connection.username" value="crmuser"/> <property name="hibernate.connection.password" value="mypass"/> <property name="hibernate.c3p0.min_size" value="5"/> <property name="hibernate.c3p0.max_size" value="20"/> <property name="hibernate.c3p0.idleTestPeriod" value="30"/> <property name="hibernate.c3p0.timeout" value="0"/> <property name="hibernate.c3p0.max_statements" value="0"/> <property name="hibernate.format_sql" value="true"/> <property name="hibernate.query.jpaql_strict_compliance" value="false"/> <property name="hibernate.validator.apply_to_ddl" value="false"/> <property name="hibernate.validator.autoregister_listeners" value="false"/> <property name="hibernate.archive.autodetection" value="class, hbm"/> <property name="hibernate.hbm2ddl.auto" value="create"/> </properties> </persistence-unit> </persistence>
编辑 :这是我获取EntityManager并保持的方式:
public void persist() { EntityManager em = entityManager(); try { em.getTransaction().begin(); em.persist(this); em.getTransaction().commit(); } finally { em.close(); } } public static EntityManager entityManager() { return EMF.get().createEntityManager(); }
事实证明这很简单:直接在persistence.xml文件中列出这些类。armandino和MikelRascher都使我得到了这个答案,尽管这是间接的,但对他们来说却是支柱。
这是我现在正在使用的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" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="crm"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <class>com.example.Language</class> <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/crm"/> <property name="hibernate.connection.username" value="myuser"/> <property name="hibernate.connection.password" value="mypass"/> <property name="hibernate.c3p0.min_size" value="5"/> <property name="hibernate.c3p0.max_size" value="20"/> <property name="hibernate.c3p0.idleTestPeriod" value="30"/> <property name="hibernate.c3p0.timeout" value="0"/> <property name="hibernate.c3p0.max_statements" value="0"/> <!--property name="hibernate.show_sql" value="true"/>--> <property name="hibernate.format_sql" value="true"/> <property name="hibernate.query.jpaql_strict_compliance" value="false"/> <property name="hibernate.validator.apply_to_ddl" value="false"/> <property name="hibernate.validator.autoregister_listeners" value="false"/> <property name="hibernate.archive.autodetection" value="class, hbm"/> <property name="hibernate.hbm2ddl.auto" value="create"/> </properties> </persistence-unit> </persistence>