Simple H2 and Hibernate/JPA

Question

使用H2作为数据库、JPA和Hibernate进行简单测试。不会给出可识别的错误，但它不会持久化实体。当然，我错过了一些非常简单的

META-INF/：中的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="thePersistenceUnit" transaction-type="RESOURCE_LOCAL">
     <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <class>entities.Person</class>
    <properties>
        <property name="connection.driver_class" value="org.h2.Driver"/>
        <property name="hibernate.connection.url" value="jdbc:h2:./db/repository"/>
        <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>
        <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
        <property name="hibernate.show_sql" value="true" />
    </properties>
</persistence-unit>

简单的实体：

@Entity
public class Person {
    @Id
    @GeneratedValue
    private Integer id;
    private String firstName;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
}

测试：

public class Testing {
    @Test
    public void test2(){
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("thePersistenceUnit");
        EntityManager theManager = factory.createEntityManager();
        assertNotNull(theManager);
        Person person = new Person();
        person.setFirstName("ana");
        theManager.persist(person);
        System.out.println(person.getId());
        Person p = (Person)theManager.find(Person.class, 1);
        System.out.println(person.getId());
        assertNotNull(p);
    }
}

结果：

Aug 16, 2013 1:48:20 PM org.hibernate.annotations.common.Version <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final}
Aug 16, 2013 1:48:20 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.0.1.Final}
Aug 16, 2013 1:48:20 PM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
Aug 16, 2013 1:48:20 PM org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
Aug 16, 2013 1:48:21 PM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000402: Using Hibernate built-in connection pool (not for production use!)
Aug 16, 2013 1:48:21 PM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH000148: No JDBC Driver class was specified by property hibernate.connection.driver_class
Aug 16, 2013 1:48:21 PM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000115: Hibernate connection pool size: 20
Aug 16, 2013 1:48:21 PM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000006: Autocommit mode: true
Aug 16, 2013 1:48:21 PM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000401: using driver [null] at URL [jdbc:h2:./db/repository]
Aug 16, 2013 1:48:21 PM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000046: Connection properties: {autocommit=true, release_mode=auto}
Aug 16, 2013 1:48:21 PM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
Aug 16, 2013 1:48:21 PM org.hibernate.engine.jdbc.internal.LobCreatorBuilder useContextualLobCreation
INFO: HHH000423: Disabling contextual LOB creation as JDBC driver reported JDBC version [3] less than 4
Aug 16, 2013 1:48:21 PM org.hibernate.engine.transaction.internal.TransactionFactoryInitiator initiateService
INFO: HHH000268: Transaction strategy: org.hibernate.engine.transaction.internal.jdbc.JdbcTransactionFactory
Aug 16, 2013 1:48:21 PM org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory <init>
INFO: HHH000397: Using ASTQueryTranslatorFactory
Aug 16, 2013 1:48:21 PM org.hibernate.tool.hbm2ddl.SchemaExport execute
INFO: HHH000227: Running hbm2ddl schema export
Aug 16, 2013 1:48:21 PM org.hibernate.tool.hbm2ddl.SchemaExport execute
INFO: HHH000230: Schema export complete
Hibernate: drop table Person if exists
Hibernate: create table Person (id integer generated by default as identity, firstName varchar(255), lastName varchar(255), primary key (id))
null
Hibernate: select person0_.id as id0_0_, person0_.firstName as firstName0_0_, person0_.lastName as lastName0_0_ from Person person0_ where person0_.id=?
null
junit.framework.AssertionFailedError
    at test.Testing.test2(Testing.java:49)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

问题是：为什么它不持久化实例/为什么它不抛出任何错误等？

Answer 1

您试图在不打开事务的情况下将记录持久化到数据库中。这是不可能的。你应该做的是：

    EntityManager theManager = factory.createEntityManager();
    theManager .getTransaction().begin();
    Person person = new Person();
    person.setFirstName("ana");
    theManager.persist(person);
    theManager.getTransaction().commit();