JPA读取但不会持续

我的Java Web App从数据库中读取数据，但是当我尝试写入内容时，JPA说没关系，但数据库没有更改。我称之为“合并”方法，数据不会保存在数据库中，只能保存在内存中。我可以直接进入SELECT数据库并查看旧数据。但是，Java控制台不会抛出任何异常，如上所见。JPA读取但不会持续

Java控制台：

INFO: [EL Finest]: 2011-10-14 15:02:41.847--UnitOfWork(13027895)--Thread(Thread[http-thread-pool-8080-(6),10,Grizzly])--Merge clone with references user1

更改密码的方法，该方法被调用：

public static User changePassword(String username, String oldPassword, String newPassword){ 
     User user = userFacade.find(username); 
     if(user != null && user.getPassword().equals(oldPassword)){ 
      user.setPassword(newPassword); 
      userFacade.edit(user); // supposed to save the new password on database, but it's not 
      // at this point, the user has a new password on memory, but on database the password is still the old one 
      return user; 
     } 
     return null; 
    }

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="APP1PU" transaction-type="RESOURCE_LOCAL"> 
     <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> 
     <class>com.company.User</class> 
     <properties> 
      <property name="javax.persistence.jdbc.url" value="jdbc:mysql://127.0.0.1:3306/app1"/> 
      <property name="javax.persistence.jdbc.password" value="12345"/> 
      <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/> 
      <property name="javax.persistence.jdbc.user" value="root"/> 
      <property name="eclipselink.logging.level" value="FINEST"/> 
     </properties> 
    </persistence-unit> 
</persistence>

User.java：

@Entity 
@Table(name = "user") 
@Cache (
    type=CacheType.NONE 
    ) 
public class User implements Serializable { 
    private static final long serialVersionUID = 1L; 

    @Id 
    @Basic(optional = false) 
    private String username; 

    @Basic(optional = false) 
    private String password; 

    public String getUsername() { 
     return username; 
    } 

    public void setUsername(String username) { 
     this.username = username; 
    } 

    public String getPassword() { 
     return password; 
    } 

    public void setPassword(String password) { 
     this.password = password; 
    } 
}

UserFacade.java

public class UserFacade { 
    private EntityManagerFactory emf = Persistence.createEntityManagerFactory("APP1PU"); 

    private EntityManager em; 

    protected EntityManager getEntityManager() { 
     if(em == null){ 
      em = emf.createEntityManager(); 
     } 
     return em; 
    } 

    public void create(User entity) { 
     getEntityManager().persist(entity); 
    } 

    public void edit(User entity) { 
     getEntityManager().merge(entity); 
    } 

    public void remove(User entity) { 
     getEntityManager().remove(getEntityManager().merge(entity)); 
    } 

    public User find(Object id) { 
     return getEntityManager().find(entityClass, id); 
    } 

}

任何人都可以弄清楚为什么这种行为？或者有一些我可以做的测试建议？

在此先感谢！

来源

2011-10-14 André

尝试写入操作后entityManager.flush()。或者在写入操作之前开始一个事务（entityManager.getTransaction().begin()），然后在最后关闭它（entityManager.getTransaction().commit()）

来源

2011-10-14 18:25:28

谢谢，Andrei！它的工作......我习惯于在**'persistence.xml'**设置**'transaction-type =“JTA”'**，但是这次我需要将它改为**'transaction-type =“RESOURCE_LOCAL”**，并忘记我必须手动控制交易。再次感谢！ –

添加此（entityManager.getTransaction（）。begin（））和（entityManager.getTransaction（）。commit（））会导致以下异常：但entityManager.flush（）起作用。异常名称：java.lang.IllegalStateException：不允许在共享EntityManager上创建事务 - 使用Spring事务或EJB CMT代替 – Sriram

JPA读取但不会持续

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