Question

我不明白为什么我的应用程序会删除异常＆＃34; Field＆＃39; Id_employeer＆＃39;没有默认值＆＃34;。

Id_employeer是我的主键，当我尝试将任何信息保存到我的数据库时，我得到了这个例外，但是，当我尝试从DB读取信息时，它正在工作。

我在StackOverflow上阅读了主题，但我仍然不了解我的应用中的答案。我正在使用Hibernate 5.2.11。

我的CharacterInfo.hbm.xml：

    <?xml version="1.0"?>

<!--
  ~ Hibernate, Relational Persistence for Idiomatic Java
  ~
  ~ License: GNU Lesser General Public License (LGPL), version 2.1 or later.
  ~ See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
  -->
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

    <class name="CharacterInfo" table="employees">
        <id name="Id" column="id_employeer">
            <generator class="native"/>
        </id>
        <property name="Login" column="employeer_login"/>



    </class>

</hibernate-mapping>

我的HibernateUtility：

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import java.util.List;


public class HibernateUtility {


    SessionFactory sessionFactory;

    public void saving(Object object){
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        session.save( object);
        //session.save( new CharacterInfo().getLogin());
        session.getTransaction().commit();
        session.close();
    }

    public void reading(){
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        List result = session.createQuery("from CharacterInfo").list();
        for ( CharacterInfo characterInfo : (List<CharacterInfo>) result ) {
            System.out.println( "CharacterInfo (" + characterInfo.getLogin() + ") : " + characterInfo.getLogin() );
        }
        session.getTransaction().commit();
        session.close();
    }


    protected void setUp() throws Exception {

        final StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure()
                .build();

        try {
            sessionFactory = new MetadataSources(registry).buildMetadata().buildSessionFactory();


        } catch (Exception e) {
            StandardServiceRegistryBuilder.destroy(registry);
        }
    }




}

下一个CharacterInfo类

import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;


@Entity
@Table( name = "employees")
public class CharacterInfo {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "Id_employeer")
    private int id ;

    @Column(name = "employeer_Login")
    private String login;


    public CharacterInfo() {}

    public int getId() {
        return id;

    }

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


    public String getLogin() {
        return login;
    }

    public void setLogin(String login) {
        this.login = login;
    }



}

主要班级

public class main {


    public static void main(String args[]) throws Exception {
        HibernateUtility hibernateUtility = new HibernateUtility();
        CharacterInfo characterInfo = new CharacterInfo();
        characterInfo.setId(1);
        characterInfo.setLogin("PawJaw");
        hibernateUtility.setUp();
        hibernateUtility.saving(characterInfo);


    }
}

并在最后的例外

错误：字段＆＃39; Id_employeer＆＃39;没有默认值Exception in 线程＆＃34;主要＆＃34; org.hibernate.exception.GenericJDBCException：不能执行声明 org.hibernate.exception.internal.StandardSQLExceptionConverter.convert（StandardSQLExceptionConverter.java:47）在 org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert（SqlExceptionHelper.java:111）在 org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert（SqlExceptionHelper.java:97）在 org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate（ResultSetReturnImpl.java:178）在 org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract（GetGeneratedKeysDelegate.java:57）在 org.hibernate.id.insert.AbstractReturningDelegate.performInsert（AbstractReturningDelegate.java:42）在 org.hibernate.persister.entity.AbstractEntityPersister.insert（AbstractEntityPersister.java:2919）在 org.hibernate.persister.entity.AbstractEntityPersister.insert（AbstractEntityPersister.java:3490）在 org.hibernate.action.internal.EntityIdentityInsertAction.execute（EntityIdentityInsertAction.java:81）在org.hibernate.engine.spi.ActionQueue.execute（ActionQueue.java:626）在 org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction（ActionQueue.java:280）在 org.hibernate.engine.spi.ActionQueue.addInsertAction（ActionQueue.java:261）在 org.hibernate.engine.spi.ActionQueue.addAction（ActionQueue.java:306）在 org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction（AbstractSaveEventListener.java:318）在 org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate（AbstractSaveEventListener.java:275）在 org.hibernate.event.internal.AbstractSaveEventListener.performSave（AbstractSaveEventListener.java:182）在 org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId（AbstractSaveEventListener.java:113）在 org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId（DefaultSaveOrUpdateEventListener.java:192）在 org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId（DefaultSaveEventListener.java:38）在 org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient（DefaultSaveOrUpdateEventListener.java:177）在 org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate（DefaultSaveEventListener.java:32）在 org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate（DefaultSaveOrUpdateEventListener.java:73）在org.hibernate.internal.SessionImpl.fireSave（SessionImpl.java:691）在org.hibernate.internal.SessionImpl.save（SessionImpl.java:683）at org.hibernate.internal.SessionImpl.save（SessionImpl.java:678）at HibernateUtility.saving（HibernateUtility.java:17）at main.main（main.java:10）引起：java.sql.SQLException：Field ＆＃39; Id_employeer＆＃39;没有默认值 com.mysql.jdbc.SQLError.createSQLException（SQLError.java:964）at at com.mysql.jdbc.MysqlIO.checkErrorPacket（MysqlIO.java:3973）at at com.mysql.jdbc.MysqlIO.checkErrorPacket（MysqlIO.java:3909）at at com.mysql.jdbc.MysqlIO.sendCommand（MysqlIO.java:2527）at at com.mysql.jdbc.MysqlIO.sqlQueryDirect（MysqlIO.java:2680）at at com.mysql.jdbc.ConnectionImpl.execSQL（ConnectionImpl.java:2487）at com.mysql.jdbc.PreparedStatement.executeInternal（PreparedStatement.java:1858）在 com.mysql.jdbc.PreparedStatement.executeUpdateInternal（PreparedStatement.java:2079）在 com.mysql.jdbc.PreparedStatement.executeUpdateInternal（PreparedStatement.java:2013）在 com.mysql.jdbc.PreparedStatement.executeLargeUpdate（PreparedStatement.java:5104）在 com.mysql.jdbc.PreparedStatement.executeUpdate（PreparedStatement.java:1998）在 org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate（ResultSetReturnImpl.java:175） ......还有23个

Answer 1

首先，如果您正在使用Hibernate注释，则不需要使用Hibernate XML映射文件。

您的错误可能是因为您的数据库架构。 Id_employeer列不是自动增量。

Field＆＃39; Id_employeer＆＃39;没有默认值

1 个答案: