hibernate建表一对多 一的一方控制多的方

级联操作，操作class对象的时候 级联操作 student

Classes.java文件

 package cn.itcast.hiberate.sh.domain;

 import java.util.Set;

 public class Classes {
     private Long cid;
     private String cname;
     private String description;
     public String getDescription() {
         return description;
     }
     public Classes(String cname, String description) {
         super();
         this.cname = cname;
         this.description = description;
     }
     public Classes(Long cid, String cname, String description,
             Set<Student> students) {
         super();
         this.cid = cid;
         this.cname = cname;
         this.description = description;
         this.students = students;
     }
     public Classes() {
         // TODO Auto-generated constructor stub
     }
     public void setDescription(String description) {
         this.description = description;
     }
     private Set<Student> students;
     public Long getCid() {
         return cid;
     }
     public void setCid(Long cid) {
         this.cid = cid;
     }
     public String getCname() {
         return cname;
     }
     public void setCname(String cname) {
         this.cname = cname;
     }
     public Set<Student> getStudents() {
         return students;
     }
     public void setStudents(Set<Student> students) {
         this.students = students;
     }

 }

Classes.hbm.xml

建立一对多的关系

 <?xml version="1.0" encoding="utf-8"?>
 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 <hibernate-mapping>
     <class name="cn.itcast.hiberate.sh.domain.Classes">
         <id name="cid" length="5" type="java.lang.Long">
             <generator class="increment"></generator>
         </id>
         <property name="cname" length="20" type="java.lang.String"></property>

         <property name="description" length="100" type="java.lang.String"></property>
         <!--
             set元素对应类中的set集合
             通过set元素使classes表与student表建立关联
                key是通过外键的形式让两张表建立关联
                one-to-many是通过类的形式让两个类建立关联

             cascade 级联
                save-update
                    1、当 保存班级的时候，对学生进行怎么样的操作
                         如果学生对象在数据库中没有对应的值，这个时候会执行save操作
                         如果学生对象在数据库中有对应的值，这个时候会执行update操作
                delete
                all
             inverse  维护关系
                true      不维护关系
                false     维护关系
                default   false
          -->
         <set name="students" cascade="save-update" inverse="true">
             <!--
                 key是用来描述外键
              -->
             <key>
                 <column name="cid"></column>
             </key>
             <one-to-many class="cn.itcast.hiberate.sh.domain.Student"/>
         </set>
     </class>
 </hibernate-mapping>

Student.java

 package cn.itcast.hiberate.sh.domain;

 public class Student {
     private Long sid;
     private String sname;
     private String description;
     public Long getSid() {
         return sid;
     }
     public void setSid(Long sid) {
         this.sid = sid;
     }
     public Student(String sname, String description) {
         super();
         this.sname = sname;
         this.description = description;
     }
     public Student() {
         // TODO Auto-generated constructor stub
     }
     public String getSname() {
         return sname;
     }
     public void setSname(String sname) {
         this.sname = sname;
     }
     public String getDescription() {
         return description;
     }
     public void setDescription(String description) {
         this.description = description;
     }

 }

Test.java

 package cn.itcast.hibernate.sh.test;

 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;

 import org.hibernate.Session;
 import org.hibernate.Transaction;
 import org.hibernate.annotations.Type;
 import org.junit.Test;

 import cn.itcast.hiberate.sh.domain.Classes;
 import cn.itcast.hiberate.sh.domain.Student;
 import cn.itcast.hibernate.sh.utils.HiberanteUtils;

 /**
  * 1、新建一个班级
  * 2、新建一个学生
  * 3、新建一个班级的时候同时新建一个学生
  * 4、已经存在一个班级，新建一个学生，建立学生与班级之间的关系
  * 5、已经存在一个学生，新建一个班级，把学生加入到该班级
  * 6、把一个学生从一个班级转移到另一个班级
  * 7、解析一个班级和一个学生之间的关系
  * 8、解除一个班级和一些学生之间的关系
  * 9、解除该班级和所有的学生之间的关系
  * 10、已经存在一个班级，已经存在一个学生，建立该班级与该学生之间的关系
  * 11、已经存在一个班级，已经存在多个学生，建立多个学生与班级之间的关系
  * 12、删除学生
  * 13、删除班级
  *     删除班级的时候同时删除学生
  *     在删除班级之前，解除班级和学生之间的关系
  * @author Think
  *
  */
 public class OneToManySingleTest extends HiberanteUtils{
     @Test
     public void testSaveClasses(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Classes classes = new Classes();
         classes.setCname("传智上海云一期");
         classes.setDescription("很牛");
         session.save(classes);
         transaction.commit();
         session.close();
     }

     @Test
     public void testSaveStudent(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Student student = new Student();
         student.setSname("班长");
         student.setDescription("老牛：很牛");
         session.save(student);
         transaction.commit();
         session.close();
     }

     @Test
     public void testSaveClasses_Student(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();

         Classes classes = new Classes();
         classes.setCname("传智上海云二期:");
         classes.setDescription("很牛X");

         Student student = new Student();
         student.setSname("班长");
         student.setDescription("老牛：很牛X");

         session.save(student);
         session.save(classes);
         transaction.commit();
         session.close();
     }

     /**
      * 在保存班级的时候，级联保存学生
      */
     @Test
     public void testSaveClasses_Cascade_Student_Save(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();

         Classes classes = new Classes();
         classes.setCname("传智上海云三期:");
         classes.setDescription("很牛XX");

         Student student = new Student();
         student.setSname("班长");
         student.setDescription("老牛：很牛XX");

         Set<Student> students = new HashSet<Student>();
         students.add(student);

         //建立classes与student之间的关联
         classes.setStudents(students);
         session.save(classes);
         transaction.commit();
         session.close();
     }

     @Test
     public void testSaveClasses_Cascade_Student_Update(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();

         Classes classes = new Classes();
         classes.setCname("传智上海云四期:");
         classes.setDescription("很牛XXX");

         Student student = (Student)session.get(Student.class, 1L);

         student.setSname("班秘");

         Set<Student> students = new HashSet<Student>();
         students.add(student);

         classes.setStudents(students);

         session.save(classes);
         transaction.commit();
         session.close();
     }

     @Test
     public void testUpdateClasses_Cascade_Student_Save(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Classes classes = (Classes)session.get(Classes.class, 5L);
         Student student = new Student();
         student.setSname("班花");
         student.setDescription("稀有人物");
         classes.getStudents().add(student);
         transaction.commit();
         session.close();
     }

     @Test
     public void testUpdateClasses_Cascade_Student_Update(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Classes classes = (Classes)session.get(Classes.class, 5L);
         Set<Student> students = classes.getStudents();//为cid为5的班级的所有的学生
 //        for(Student student:students){
 //            student.setDescription("压力山大");
 //        }
         transaction.commit();
         session.close();
     }

     /**
      * 一个错误的演示
      */
     @Test
     public void testSaveClasses_Cascade_Student_Save_Error(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();

         Classes classes = new Classes();
         classes.setCname("传智上海云六期:");
         classes.setDescription("很牛XXXXXX");

         Student student = new Student();
         student.setSname("班长XXXXXX");
         student.setDescription("老牛：很牛XXXXXX");

         Set<Student> students = new HashSet<Student>();
         students.add(student);

         //建立classes与student之间的关联
         classes.setStudents(students);
         session.save(classes);
         transaction.commit();
         session.close();
     }

     /**
      * 已经存在一个班级，新建一个学生，建立学生与班级之间的关系
      *    通过更新班级级联保存学生  cascade
      *    建立班级和学生之间的关系  inverse
      */
     @Test
     public void testSaveStudent_R_1(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Student student = new Student();
         student.setSname("技术班长");
         student.setDescription("大神");
         Classes classes = (Classes)session.get(Classes.class, 1L);

         classes.getStudents().add(student);

         transaction.commit();
         session.close();
     }

     /**
      *     Hibernate: select classes0_.cid as cid0_0_, classes0_.cname as cname0_0_, classes0_.description as descript3_0_0_ from Classes classes0_ where classes0_.cid=?
         Hibernate: select max(sid) from Student
         Hibernate: select students0_.cid as cid0_1_, students0_.sid as sid1_, students0_.sid as sid1_0_, students0_.sname as sname1_0_, students0_.description as descript3_1_0_ from Student students0_ where students0_.cid=?
         Hibernate: insert into Student (sname, description, sid) values (?, ?, ?)
         更新关系的操作
         Hibernate: update Student set cid=? where sid=?
      */
     @Test
     public void testSaveStudent_R_2(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Student student = new Student();
         student.setSname("技术班长");
         student.setDescription("大神");
         Classes classes = (Classes)session.get(Classes.class, 1L);

         session.save(student);

         classes.getStudents().add(student);

         transaction.commit();
         session.close();
     }

     /**
      * 已经存在一个学生，新建一个班级，把学生加入到该班级
      */
     @Test
     public void testSaveClasses_R(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();

         Classes classes = new Classes();
         classes.setCname("老毕基础加强班");
         classes.setDescription("必看，杀手锏");

         Student student = (Student)session.get(Student.class, 2L);
         Set<Student> students = new HashSet<Student>();
         students.add(student);
         classes.setStudents(students);

         session.save(classes);
         transaction.commit();
         session.close();
     }

     /**
      * 把一个学生从一个班级转移到另一个班级
      *     Hibernate: select classes0_.cid as cid0_0_, classes0_.cname as cname0_0_, classes0_.description as descript3_0_0_ from Classes classes0_ where classes0_.cid=?
         Hibernate: select classes0_.cid as cid0_0_, classes0_.cname as cname0_0_, classes0_.description as descript3_0_0_ from Classes classes0_ where classes0_.cid=?
         Hibernate: select student0_.sid as sid1_0_, student0_.sname as sname1_0_, student0_.description as descript3_1_0_ from Student student0_ where student0_.sid=?
         Hibernate: select students0_.cid as cid0_1_, students0_.sid as sid1_, students0_.sid as sid1_0_, students0_.sname as sname1_0_, students0_.description as descript3_1_0_ from Student students0_ where students0_.cid=?
         Hibernate: select students0_.cid as cid0_1_, students0_.sid as sid1_, students0_.sid as sid1_0_, students0_.sname as sname1_0_, students0_.description as descript3_1_0_ from Student students0_ where students0_.cid=?
         Hibernate: update Student set cid=null where cid=? and sid=?
         Hibernate: update Student set cid=? where sid=?
      */
     @Test
     public void testTransformClass(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         //Classes classes5 = (Classes)session.get(Classes.class, 5L);
         Classes classes6 = (Classes)session.get(Classes.class, 6L);
         Student student = (Student)session.get(Student.class, 1L);
         //classes5.getStudents().remove(student);
         classes6.getStudents().add(student);
         transaction.commit();
         session.close();
     }

     /**
      * 解除一个班级和一些学生之间的关系
      */

     @Test
     public void testR_Some(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Classes classes = (Classes)session.get(Classes.class, 1L);
         Set<Student> students = classes.getStudents();
 //        for(Student student:students){
 //            if(student.getSid().longValue()==6||student.getSid().longValue()==7){
 //                students.remove(student);
 //            }
 //        }
         //set-->list
         List<Student> sList = new ArrayList<Student>(students);
         for(int i=0;i<sList.size();i++){
             if(sList.get(i).getSid().longValue()==6||sList.get(i).getSid().longValue()==7){
                 sList.remove(sList.get(i));
                 i--;
             }
         }

         students = new HashSet<Student>(sList);
         classes.setStudents(students);
         /**
          * 增强for循环只能修改一次
          *   1、用普通的for循环
          *   2、新建一个set集合，把原来的set集合要保留的数据存放到新的set集合中
          */
         transaction.commit();
         session.close();
     }

     /*
      * classes.setStudents(null);直接把班级针对student的集合设置为null
      */
     @Test
     public void testRealseAll(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Classes classes = (Classes)session.get(Classes.class, 1L);
 //        Set<Student> students = classes.getStudents();
 //        students.clear();
         classes.setStudents(null);
         transaction.commit();
         session.close();
     }

     /**
      * 已经存在一个班级，已经存在一个学生，建立该班级与该学生之间的关系
      * 11、已经存在一个班级，已经存在多个学生，建立多个学生与班级之间的关系
      */

     @Test
     public void testDeleteStudent(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Student student = (Student)session.get(Student.class, 8L);
         session.delete(student);
         transaction.commit();
         session.close();
     }

     //这个时候必须保证inverse="false"才能保证能够维持 Classes和Student之间的关系， 如果为inverse="true"并且cascade="save-update"会报错，外键         //约束错误
     @Test
     public void testDeleteClasses(){
         Session session = sessionFactory.openSession();
         Transaction transaction = session.beginTransaction();
         Classes classes = (Classes)session.get(Classes.class, 5L);
         //classes.setStudents(null);　　　　　　　　//因为inverse="true"所以，这句话对数据库没作用，没有关联关系了
         session.delete(classes);
         transaction.commit();
         session.close();
     }
     
　　　　//这个时候用到了 Classes.hbm.xml中的级联属性  cascade="delete"（用all就包括它们两个属性）inverse="true"也是没有关系的
  @Test 
 public void testDeleteClasses_Cascade(){ 
         Session session = sessionFactory.openSession(); 

         Transaction transaction = session.beginTransaction(); 
         Classes classes = (Classes)session.get(Classes.class, 5L); 
         session.delete(classes); 
         transaction.commit(); 
         session.close(); 
    } 

 }