Hibernate多对一双向关联(Annotation配置)

Hibernate多对一双向关联(Annotation配置)

Department.java

package  com.many2one.bean;

import  java.util.Set;

import  javax.persistence.Column;
import  javax.persistence.Entity;
import  javax.persistence.GeneratedValue;
import  javax.persistence.GenerationType;
import  javax.persistence.Id;
import  javax.persistence.OneToMany;
import  javax.persistence.Table;

@Entity
@Table(name = " department " ,catalog = " Hibernate_Many2One " )
public   class  Department {
    
     private   int  id;
     private  String name;
     private  Set < Employee >  sets;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = " id " )
     public   int  getId() {
         return  id;
    }
     public   void  setId( int  id) {
         this .id  =  id;
    }
    @Column(name = " name " )
     public  String getName() {
         return  name;
    }
     public   void  setName(String name) {
         this .name  =  name;
    }
    @OneToMany(mappedBy = " department " )
     public  Set < Employee >  getSets() {
         return  sets;
    }
     public   void  setSets(Set < Employee >  sets) {
         this .sets  =  sets;
    }
    
}

Employee.java

package  com.many2one.bean;

import  javax.persistence.CascadeType;
import  javax.persistence.Column;
import  javax.persistence.Entity;
import  javax.persistence.GeneratedValue;
import  javax.persistence.GenerationType;
import  javax.persistence.Id;
import  javax.persistence.JoinColumn;
import  javax.persistence.ManyToOne;
import  javax.persistence.Table;

@Entity
@Table(name = " employee " ,catalog = " Hibernate_Many2One " )
public   class  Employee {
    
     private   int  id;
     private  String name;
     private  Department department;
    @Id
    @Column(name = " id " )
    @GeneratedValue(strategy = GenerationType.AUTO)
     public   int  getId() {
         return  id;
    }
     public   void  setId( int  id) {
         this .id  =  id;
    }
    @Column(name = " name " )
     public  String getName() {
         return  name;
    }
     public   void  setName(String name) {
         this .name  =  name;
    }
    @ManyToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = " deptid " )
     public  Department getDepartment() {
         return  department;
    }
     public   void  setDepartment(Department department) {
         this .department  =  department;
    }
    
    
}

导出的sql

create   table  Hibernate_Many2One.department (
        id  integer   not   null  auto_increment,
        name  varchar ( 255 ),
         primary   key  (id)
    )

     create   table  Hibernate_Many2One.employee (
        id  integer   not   null  auto_increment,
        name  varchar ( 255 ),
        deptid  integer ,
         primary   key  (id)
    )

     alter   table  Hibernate_Many2One.employee 
         add   index  FK4722E6AE3829E242 (deptid), 
         add   constraint  FK4722E6AE3829E242 
         foreign   key  (deptid) 
         references  Hibernate_Many2One.department (id)

测试代码

@Test
     public   void  insert(){
        Session session = HibernateSessionFactory.getSession();
        Transaction transaction = session.beginTransaction();
         try  {
            transaction.begin();
            Department department = new  Department();
            department.setName( " 软件测试部 " );
            Employee employee = new  Employee();
            employee.setName( " 张三 " );
            employee.setDepartment(department);
            session.save(employee);
            transaction.commit();
        }  catch  (HibernateException e) {
            e.printStackTrace();
        }
    }
    
    
    @Test
     public   void  select(){
        Session session = HibernateSessionFactory.getSession();
         try  {
            Employee employee = (Employee) session.get(Employee. class ,  1 );
            System.out.println(employee.getName());
            System.out.println(employee.getDepartment().getName());
        }  catch  (HibernateException e) {
            e.printStackTrace();
        }
    }