对象不是声明类-Hibernate的实例 [英] object is not an instance of declaring class -Hibernate

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本文介绍了对象不是声明类-Hibernate的实例的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我是HIbernate的新手，正在练习一对多映射的例子，但我不明白为什么它会抛出错误。

1）员工。 java 

  package com.common.pojo; 
 
 import java.util.Set; 
 
公共类员工
 {
 private int id; 
私人字符串名称; 
私人设置证书; 
 
 public Employee（）{} 
 $ b $ public Employee（String name）{
 
 this.name = name; 
 
} 
 public int getId（）{
 return id; 
} 
 
 public void setId（int id）{
 this.id = id; 
} 
 
 public String getName（）{
 return name; 
} 
 
 public void setName（String name）{
 this.name = name; 
} 
 
 public Set getCertificate（）{
 return certificate; 
} 
 
 public void setCertificate（Set certificate）{
 this.certificate = certificate; 
} 
 
}



2）Certificate.java p> 

  package com.common.pojo; 
 
公共类证书
 {
 private int id; 
私人字符串名称; 
 
 public Certificate（）{} 
 public Certificate（String name）
 {
 this.name = name; 
} 
 
 public int getId（）{
 return id; 
} 
 
 public void setId（int id）{
 this.id = id; 
} 
 
 public String getName（）{
 return name; 
} 
 
 public void setName（String name）{
 this.name = name; 
 
 
 code 
 $ b 3）Employee.hbm.xml 
 <？xml version =1.0encoding =UTF-8？> 
<！DOCTYPE hibernate-mapping PUBLIC 
 -  // Hibernate / Hibernate映射DTD 3.0 // EN
http://www.hibernate.org/dtd/hibernate-mapping -3.0.dtd> 
 
< hibernate-mapping> 
< class table =Employeename =com.common.pojo.Employee> 
< meta attribute =class-description> 
雇员类
< / meta> 
< id name =idcolumn =idtype =int> 
< generator class =native>< / generator> 
< / id> 
< property name =namecolumn =nametype =string>< / property> 
< set name =certificatecascade =all> 
< key column =id>< / key> 
 < / set> 
< / class> 
 
 
< class table =Certificatename =com.common.pojo.Certificate> 
< meta attribute =class-description> 
证书课程
< / meta> 
< id name =idcolumn =cer_idtype =int> 
< generator class =native>< / generator> 
< / id> 
< property name =namecolumn =cer_nametype =string>< / property> 
 
< / class> 
 
 
< / hibernate-mapping> 
  
 
 
 <4> hibernate.cfg.xml  
 
 
 <？xml version =1.0encoding =UTF-8？> 
<！DOCTYPE hibernate-configuration PUBLIC 
 -  // Hibernate / Hibernate配置DTD 3.0 // EN
http://www.hibernate.org/dtd/hibernate-configuration -3.0.dtd> 
 
< hibernate-configuration> 
< session-factory> 
< property name =hibernate.dilect> org.hibernate.dialect.HSQLDialect< / property> 
< property name =hibernate.driver.connection_class> org.hsqldb.jdbcDriver< / property> 
< property name =hibernate.connection.url> jdbc：hsqldb：hsql：// localhost /< / property> 
< property name =hibernate.connection.username> SA< / property> 
< property name =hibernate.connection.password>< / property> 
< property name =show_sql> true< / property> 
 
< mapping resource =Employee.hbm.xml/> 
< / session-factory> 
< / hibernate-configuration> 
  
 
 
 <5> TestApp.java 
  package com.common.mainapp; 
 
 import java.util.HashSet; 
 import java.util.Set; 
 
 import org.hibernate.HibernateException; 
 import org.hibernate.Session; 
 import org.hibernate.SessionFactory; 
 import org.hibernate.Transaction; 
导入org.hibernate.cfg.Configuration; 
 
导入com.common.pojo.Employee; 
 
 public class TestApp {
 
 private static SessionFactory factory; 
 @SuppressWarnings（deprecation）
 public static void main（String [] args）{
 try 
 {
 factory = new Configuration（）。configure（） .buildSessionFactory（）; 
 
 catch（HibernateException异常）
 {
 exception.printStackTrace（）; 
} 
 TestApp app = new TestApp（）; 
 Set certificate = new HashSet（）; 
 certificate.add（BE）; 
 certificate.add（MBA）; 
 certificate.add（BCA）; 
 app.addEmployee（Amit，证书）; 
 Set certificate1 = new HashSet（）; 
 certificate1.add（SCJP）; 
 certificate1.add（OCJP）; 
 app.addEmployee（Sunil，certificate1）; 
} 
 public void addEmployee（String name，Set certificate）
 {
 Transaction tx = null; 
会话会话= factory.openSession（）; 
 Integer employeeId = null; 
尝试
 {
 tx = session.beginTransaction（）; 
 Employee employee = new Employee（name）; 
 employee.setCertificate（certificate）; 
 employeeId =（Integer）session.save（employee）; 
 tx.commit（）; 
 
 catch（HibernateException异常）
 {
 if（tx！= null）tx.rollback（）; 
 exception.printStackTrace（）; 
} 
 finally 
 {
 session.close（）; 
} 
} 
 
} 
  
而我已使用以下DDL命令创建了表Employee和Certificate 
 
 
 pre codeREATE TABLE CERTIFICATE 
 $ b $ cer_id int IDENTITY， 
 cer_name varchar（25），
 emp_id int 
）

并且 

  CREATE TABLE EMPLOYEE 
（
 id int IDENTITY，
 name varchar（25） 
）

但是运行后我收到错误。

  Hibernate：insert into Employee（id，name）values（default，？）
 apr 14，2014 6:34:35 EM org.hibernate .property.BasicPropertyAccessor $ BasicGetter得到
错误：HHH000122：抛出：IllegalArgumentException类：com.common.pojo.Certificate，财产的getter方法：ID 
 org.hibernate.PropertyAccessException：抛出：IllegalArgumentException发生调用COM的吸气剂。 common.pojo.Certificate.id 
在org.hibernate.property.BasicPropertyAccessor $ BasicGetter.g等（BasicPropertyAccessor.java:192）
。在org.hibernate.tuple.entity.AbstractEntityTuplizer.getIdentifier（AbstractEntityTuplizer.java:346）
。在org.hibernate.persister.entity.AbstractEntityPersister.getIdentifier（AbstractEntityPersister。 
 at org.hibernate.persister.entity.AbstractEntityPersister.isTransient（AbstractEntityPersister.java:4459）
 at org.hibernate.engine.internal.ForeignKeys.isTransient（ForeignKeys.java:243）在org.hibernate.event.internal.AbstractSaveEventListener.getEntityState（AbstractSaveEventListener.java:511）
 
在org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performSaveOrUpdate（DefaultSaveOrUpdateEventListener.java:100）
在org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate（DefaultSaveOrUpdateEventListener.java:90）
在org.hibernate.internal.SessionImpl.fireSaveOrUpdate（SessionImpl.java:680）
在org.hibernate.internal .SessionImpl.saveOrUpdate（Sessio nImpl.java:672）
在org.hibernate.engine.spi.CascadingActions $ 5.cascade（CascadingActions.java:235）
在org.hibernate.engine.internal.Cascade.cascadeToOne（Cascade.java ：352）
 at org.hibernate.engine.internal.Cascade.cascadeAssociation（Cascade.java:295）
 at org.hibernate.engine.internal.Cascade.cascadeProperty（Cascade.java:161）
 at org.hibernate.engine.internal.Cascade.cascadeCollectionElements（Cascade.java:381）
 at org.hibernate.engine.internal.Cascade.cascadeCollection（Cascade.java:321）
 at org.hibernate.engine.internal.Cascade.cascadeAssociation（Cascade.java:298）
 org.hibernate.engine.internal.Cascade.cascadeProperty（Cascade.java:161）
 org.hibernate。 engine.internal.Cascade.cascade（Cascade.java:118）
 at org.hibernate.event.internal.AbstractSaveEventListener.cascadeAfterSave（AbstractSaveEventListener.java:460）
在org.hibernate.event.internal。 AbstractSaveEventListener.performSaveOrReplicate（分区：Abst ractSaveEventListener.java:294）在org.hibernate.event.internal.AbstractSaveEventListener.performSave（AbstractSaveEventListener.java:194 
）
在org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId（AbstractSaveEventListener.java： 
 at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId（DefaultSaveOrUpdateEventListener.java:209）
 at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId（DefaultSaveEventListener.java:55）$ b在org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient（DefaultSaveOrUpdateEventListener.java:194）
 $ b在org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate（DefaultSaveEventListener.java:49）
。在组织.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate（DefaultSaveOrUpdateEventListener.java:90）
 at org.hibernate.internal.SessionImpl.fireSave（SessionIm pl.java:711）
在org.hibernate.internal.SessionImpl.save（SessionImpl.java:703）
在org.hibernate.internal.SessionImpl.save（SessionImpl.java:698）$ b在com.common.mainapp.TestApp.addEmployee处的$ b（TestApp.java:74）$ com.common.mainapp.TestApp.main处的
（TestApp.java:52）
导致：java.lang .IllegalArgumentException：对象不是在sun.reflect.NativeMethodAccessorImpl.invoke0（本地方法）中声明类
的实例$ b $ sun.reflect.NativeMethodAccessorImpl.invoke（未知源）
在sun。反射.DelegatingMethodAccessorImpl.invoke（未知源）
在java.lang.reflect.Method.invoke（未知源）
在org.hibernate.property.BasicPropertyAccessor $ BasicGetter.get（BasicPropertyAccessor.java:169） 
 ... 32 more


解决方案

已将证书映射为证书对象的集合：

 < set名称=证书casca DE = 所有 > 
< key column =id>< / key> 
 < / set>

但是在你的测试中加入 String s到那个集合：

 设置证书=新的HashSet（）; 
 certificate.add（BE）; 
 certificate.add（MBA）; 
 certificate.add（BCA）;

Java的泛型可以帮助您在编译时识别这些错误，所以更好地指定您使用的集合的元素类型，因此在添加错误的元素类型时会出现编译错误： 

  private设置< Certificate> ;证书;


I am new to HIbernate and was practicing some examples on One-to-many mapping but I am not getting why it is throwing error.

1)Employee.java

package com.common.pojo;

import java.util.Set;

public class Employee 
{
private int id;
private String name;
private Set certificate;

public Employee (){}

public Employee(String name) {

    this.name = name;

}
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public Set  getCertificate() {
    return certificate;
}

public void setCertificate(Set  certificate) {
    this.certificate = certificate;
}

}

2) Certificate.java

package com.common.pojo;

public class Certificate 
{
    private int id;
    private String name;

    public Certificate(){}
    public Certificate(String name)
    {
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

3)Employee.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class table="Employee" name="com.common.pojo.Employee">
        <meta attribute="class-description">
            Employee class
        </meta>
        <id name="id" column="id" type="int">
            <generator class="native"></generator>
        </id>
        <property name="name" column="name" type="string"></property>
        <set name="certificate" cascade="all">
            <key column="id"></key>
            <one-to-many class="com.common.pojo.Certificate" />
        </set>
    </class>


    <class table="Certificate" name="com.common.pojo.Certificate">
        <meta attribute="class-description">
            Certificate class
        </meta>
        <id name="id" column="cer_id" type="int">
            <generator class="native"></generator>
        </id>
        <property name="name" column="cer_name" type="string"></property>

    </class>


</hibernate-mapping>

4)hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory>
        <property name="hibernate.dilect">org.hibernate.dialect.HSQLDialect</property>
        <property name="hibernate.driver.connection_class">org.hsqldb.jdbcDriver</property>
        <property name="hibernate.connection.url">jdbc:hsqldb:hsql://localhost/</property>
        <property name="hibernate.connection.username">SA</property>
        <property name="hibernate.connection.password"></property>
        <property name="show_sql">true</property>

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

5)TestApp.java

package com.common.mainapp;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import com.common.pojo.Employee;

public class TestApp {

    private static SessionFactory factory;
    @SuppressWarnings("deprecation")
    public static void main(String[] args) {
        try
        {
            factory =new Configuration().configure().buildSessionFactory();
        }
        catch(HibernateException exception)
        {
            exception.printStackTrace();
        }
        TestApp app=new TestApp();
        Set certificate =new HashSet();
        certificate.add("BE");
        certificate.add("MBA");
        certificate.add("BCA");
        app.addEmployee("Amit",certificate);
        Set certificate1 =new HashSet();
        certificate1.add("SCJP");
        certificate1.add("OCJP");
        app.addEmployee("Sunil",certificate1);
    }
    public void addEmployee(String name,Set certificate)
    {
        Transaction tx=null;
        Session session=factory.openSession();
        Integer employeeId =null;
        try
        {
            tx=session.beginTransaction();   
            Employee employee=new Employee(name);
            employee.setCertificate(certificate);
            employeeId = (Integer) session.save(employee);
            tx.commit();    
        }
        catch(HibernateException exception)
        {
            if (tx!=null) tx.rollback();
            exception.printStackTrace(); 
        }
        finally
        {
            session.close();
        }
    }

}

And I have created table Employee and Certificate using below DDL command

CREATE TABLE CERTIFICATE
(
cer_id int IDENTITY,
cer_name varchar(25),
emp_id int 
)

And

CREATE TABLE EMPLOYEE
(
id int IDENTITY,
name varchar(25)
)

But after running i am getting below error.

Hibernate: insert into Employee (id, name) values (default, ?)
apr 14, 2014 6:34:35 EM org.hibernate.property.BasicPropertyAccessor$BasicGetter get
ERROR: HHH000122: IllegalArgumentException in class: com.common.pojo.Certificate, getter method of property: id
org.hibernate.PropertyAccessException: IllegalArgumentException occurred calling getter of com.common.pojo.Certificate.id
    at org.hibernate.property.BasicPropertyAccessor$BasicGetter.get(BasicPropertyAccessor.java:192)
    at org.hibernate.tuple.entity.AbstractEntityTuplizer.getIdentifier(AbstractEntityTuplizer.java:346)
    at org.hibernate.persister.entity.AbstractEntityPersister.getIdentifier(AbstractEntityPersister.java:4740)
    at org.hibernate.persister.entity.AbstractEntityPersister.isTransient(AbstractEntityPersister.java:4459)
    at org.hibernate.engine.internal.ForeignKeys.isTransient(ForeignKeys.java:243)
    at org.hibernate.event.internal.AbstractSaveEventListener.getEntityState(AbstractSaveEventListener.java:511)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:100)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
    at org.hibernate.internal.SessionImpl.fireSaveOrUpdate(SessionImpl.java:680)
    at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:672)
    at org.hibernate.engine.spi.CascadingActions$5.cascade(CascadingActions.java:235)
    at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:352)
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:295)
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
    at org.hibernate.engine.internal.Cascade.cascadeCollectionElements(Cascade.java:381)
    at org.hibernate.engine.internal.Cascade.cascadeCollection(Cascade.java:321)
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:298)
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:118)
    at org.hibernate.event.internal.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:460)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:294)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:194)
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:125)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:209)
    at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:55)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:194)
    at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:49)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
    at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:711)
    at org.hibernate.internal.SessionImpl.save(SessionImpl.java:703)
    at org.hibernate.internal.SessionImpl.save(SessionImpl.java:698)
    at com.common.mainapp.TestApp.addEmployee(TestApp.java:74)
    at com.common.mainapp.TestApp.main(TestApp.java:52)
Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.hibernate.property.BasicPropertyAccessor$BasicGetter.get(BasicPropertyAccessor.java:169)
    ... 32 more

解决方案

You've mapped the certificates as set of Certificate objects:

   <set name="certificate" cascade="all">
      <key column="id"></key>
      <one-to-many class="com.common.pojo.Certificate" />
   </set>

but in your test you add Strings to that set:

    Set certificate =new HashSet();
    certificate.add("BE");
    certificate.add("MBA");
    certificate.add("BCA");

Java's generics help you recognizing such errors on compile time, so better specify the element type of the collections you use, so you get a compilation error when adding the wrong element types:

private Set<Certificate> certificate;

这篇关于对象不是声明类-Hibernate的实例的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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