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我有一个特殊的问题。每次，我在会话上调用合并，Hibernate 都会保留一个全新的对象。我在 Spring MVC 应用程序中使用 Hibernate 3.6。

请在下面找到我的代码：

我的 hibernate.cfg.xml

<hibernate-configuration>
    <session-factory>
        <property name="dialect">org.hibernate.dialect.Oracle10gDialect </property>





        <!-- this will show us all sql statements -->
        <property name="hibernate.show_sql"> true   </property>
        <property name="connection.pool_size">1</property>


        <!--  <property name="hbm2ddl.auto">create</property>-->

        <!-- mapping files -->


        <mapping resource="com/hibernate/hbm/employee.hbm.xml"></mapping>
        </session-factory>
</hibernate-configuration>

我的员工.hbm.xml

<hibernate-mapping default-lazy="true">
    <class name="com.spring.model.Employee" table="employee">
        <id name="empId" type="long" column="empId" unsaved-value="null">
            <generator class="sequence">
                <param name="sequence">hibernate_sequence</param>
            </generator>
        </id>
        <version name="version" column="version" unsaved-value="null"
            type="long" />


        <component name="identity" class="com.spring.model.Identity">
            <property name="firstname" column="firstname" not-null="true" />
            <property name="lastname" column="lastname" not-null="true" />
            <property name="email" column="emailid" not-null="true" />
        </component>


        <!--    <property name="birthday" column="birthday"/>       -->
        <property name="fileDataBytes" column="filedata" />

        <property name="fileName" column="fileName" />
        <property name="fileContentType" column="fileContentType" />

    </class>
</hibernate-mapping>

我的模型课

  public class Employee  extends BaseModel{
   private CommonsMultipartFile fileData;


private byte[] fileDataBytes;
private String fileName;
private String fileContentType;

private Identity identity;

private long empId;
      //getters,setters /equals() on empId field 

       @Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + (int) (empId ^ (empId >>> 32));
    return result;
}


@Override
public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Employee other = (Employee) obj;
    if (empId != other.empId)
        return false;
    return true;
}

       public class BaseModel implements Serializable{
       private Long version;

       //gettes,setters

      public class Identity {
       protected String firstname;   
protected String lastname;   
  protected String email;    
        //getters.setters

我的employeeDAOImpl.java 的save方法

public long saveEmployee(Employee employee) throws Exception {
        public Employee getEmployeeById(long empId) {
        // TODO Auto-generated method stub
        return (Employee) getSessionFactory().getCurrentSession().load(Employee.class,empId);
                       }
    }
        // TODO Auto-generated method stub
        if(employee.getEmpId() == 0){
             return  (Long)getSessionFactory().getCurrentSession().save(employee);
        }else{
            Employee empInSession = getEmployeeById(employee.getEmpId());
            getSessionFactory().getCurrentSession().merge(employee);
            return  employee.getEmpId();

        }
    }

注意：我已经在 GET 循环中加载了对象，但是为了确保将对象加载到缓存中，我仍然在调用 merge() 之前加载它。理想情况下，根本不需要合并，随着对象变得持久。为什么会发生这种情况？Hibernate 使用更改的属性保存一个新对象并保存它。它不应该通过equals检查中的empId字段检查吗？

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2 回答 2

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尝试将等号和哈希码添加到您的员工类。

于 2012-05-22T12:36:48.680 回答
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好吧，这似乎是一个春天的问题。通过将 @SessionAttributes 添加到我的 Controller 类来解决。看起来无害，但实际上是问题的根源。春季论坛上的 Marten 在这里帮助了我

于 2012-05-25T07:14:16.237 回答