Question

我正在尝试将Java对象持久保存到Mysql数据库。但是我面临以下错误。

ClientDemo.java
package com.infybank;
import java.util.Scanner;
import org.hibernate.HibernateException;
public class ClientDemo {
     public static void main(String args[])
     {
         CustomerDAO custdao=new CustomerDAO();
         try
           {
             System.out.println("CREATE");
             System.out.println("Enter the customer details");
             Scanner sc=new Scanner(System.in);
             System.out.println("Enter the customer number");
             int d=sc.nextInt();
             System.out.println("Enter the customer name");
             String name=sc.next();
             Customer cust=new Customer(d,name);
             custdao.addCustomer(cust);
             System.out.println("One recort inserted");     
    }
    catch(HibernateException ex)
    {

        System.out.println("Exception "+ex);
    }
}}`

HibernateUtil.java 包com.infybank;

 import org.hibernate.SessionFactory;
 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
 import org.hibernate.cfg.Configuration;
 import org.hibernate.service.ServiceRegistry;

 public class HibernateUtil {

private static final SessionFactory sessionFactory;
static
{
    try
    {
        Configuration configuration =new Configuration().configure("/config/hibernate.cfg.xml");
        ServiceRegistry serviceRegistry=new StandardServiceRegistryBuilder()
                .applySettings(configuration.getProperties()).build();
        sessionFactory=configuration.buildSessionFactory(serviceRegistry);

    }
    catch(Throwable ex)
    {
        System.err.println("Initial sessionFactory creation failed"+ex);
        throw new ExceptionInInitializerError(ex);

    }
}
public static SessionFactory getSessionFactory()
{
    return sessionFactory;
}}

这是hibernate.cfg.xml文件

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://hibernate.org/dtd/hibernate-configuration-3.0.dtd">
 <hibernate-configuration>
 <session-factory>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernatedb</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password">Anak@1604</property>
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <mapping class="com.infybank.Customer"/>
 </session-factory>
 </hibernate-configuration>

Customer.java

package com.infybank;

import javax.persistence.Column;    
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="customer")
public class Customer {
@Id
@Column(name="CUSTOMERID")
private int customerId;
@Column(name="CUSTOMERNAME")
private String customerName;


public Customer(int id,String name)
{
    this.customerId=id;
    this.customerName=name;
}


public int getCustomerId() {
    return customerId;
}


public void setCustomerId(int customerId) {
    this.customerId = customerId;
}


public String getCustomerName() {
    return customerName;
}


public void setCustomerName(String customerName) {
    this.customerName = customerName;
}
}

CustomerDAO.java

package com.infybank;

import org.hibernate.Session;
import org.hibernate.Transaction;

public class CustomerDAO implements ICustomer{

@Override
public void addCustomer(Customer cust) {
    // TODO Auto-generated method stub
    Session session=HibernateUtil.getSessionFactory().openSession();
    Transaction tx=session.beginTransaction();
    session.save(cust);
    tx.commit();
    session.close();

}
}

错误异常org.hibernate.MappingException：未知实体：com.infybank.Customer

在尝试运行代码时遇到上述错误

Answer 1

至少Hibernate实体不应具有带有参数的此类构造函数：

    {
      name: 'backend_field_created_at',
      alias: 'createdAt',
      render: (row) => { return (<span>{`${date(row.createdAt)}`}</span>) },
      sortable: true,
      type: 'text'
    }

有关更多信息，请参见this answer。

Answer 2

默认情况下，所有实体类都应具有默认构造函数。 Hibernate要求这样做，因为它们是通过反射实例化的。

我相信您只需要向您的Customer类添加一个空的构造函数，就可以了

public Customer(){}

休眠映射异常，尽管我导入导入javax.persistence.Entity

2 个答案: