JPA不插入数据库,为什么?

时间:2011-09-04 15:40:58

标签: java mysql jpa

我是JPA的新手,我正在使用Glassfish 3和Eclipse Java EE Web开发人员的JSF 2项目。 这些是我的设置以及我尝试在数据库中保留的方式:

的persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<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="SuaParte" transaction-type="RESOURCE_LOCAL">
        <class>com.suaparte.pojo.Area</class>
            //other entities

        <properties>
            <property name="eclipselink.jdbc.batch-writing" value="JDBC"/>
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://<hostname>:3306/sua_parte"/>
            <property name="javax.persistence.jdbc.user" value=<username>/>
            <property name="javax.persistence.jdbc.password" value=<password>/>
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
        </properties>
    </persistence-unit>
</persistence>

我的实体:

@Entity
@Table(name="area")
public class Area implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(unique=true, nullable=false)
    private byte id;

    @Column(nullable=false, length=45)
    private String area;

    //bi-directional many-to-one association to Company
    @OneToMany(mappedBy="areaBean")
    private List<Company> companies;

    //getters and setters    


}

以及我如何调用我的EntityManager并尝试保留该对象:

public static void main(String[] args) {
    // TODO Auto-generated method stub
    EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("SuaParte");
    EntityManager entityManager = entityManagerFactory.createEntityManager();

    Area area = new Area();
    area.setArea("test");

    entityManager.persist(area);

}

但是当我在我的数据库中没有执行任何操作时,JPA不会将对象保留在我的表中,我做错了什么? 有什么想法吗?

1 个答案:

答案 0 :(得分:3)

你缺少transaction handling,例如

entityManager.getTransaction().begin();
entityManager.persist(area);
entityManager.getTransaction().commit();

我建议您阅读JPA和JSF集成,可能会有一些实用程序/过滤器/ JSF支持为您解决此问题。