Hibernate中双向多对多的两种配置方式

Hibernate中双向多对多的两种配置方式

1.建立多对多双向关联关系

 package cn.happy.entitys;

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

 public class Employee {
     private Integer empid;
     private String empname;
     private Set<ProEmp> emps = new HashSet<ProEmp>();

     public Set<ProEmp> getEmps() {
         return emps;
     }

     public void setEmps(Set<ProEmp> emps) {
         this.emps = emps;
     }

     public Integer getEmpid() {
         return empid;
     }

     public void setEmpid(Integer empid) {
         this.empid = empid;
     }

     public String getEmpname() {
         return empname;
     }

     public void setEmpname(String empname) {
         this.empname = empname;
     }

     public Set<ProEmp> getProjects() {
         return projects;
     }

     public void setProjects(Set<ProEmp> projects) {
         this.projects = projects;
     }

     private Set<ProEmp> projects = new HashSet<ProEmp>();
 }

Employee.java

 <?xml version="1.0"?>
 <!DOCTYPE hibernate-mapping PUBLIC
         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
         <hibernate-mapping package="cn.happy.entitys">

         <class name="Employee" table="EMPLOYEE">
         <id name="empid" column="EMPID">
          <generator class="sequence">
          <param name="sequence">STU_SID</param>
          </generator>
         </id>
         <property name="empname" type="string" column="EMPNAME"></property>

         <set name="projects" table="PROEMP" cascade="save-update">
         <key column="REMPID"></key>
         <many-to-many class="Project" column="RPROID"></many-to-many>
         </set>

         </class>

         </hibernate-mapping> 

Employee.hbm.xml

 package cn.happy.entitys;

 import java.util.Set;

 public class Project {
     private Integer proid;
     private String proname;
     private Set<ProEmp> pros;
     public Integer getProid() {
         return proid;
     }
     public Set<ProEmp> getPros() {
         return pros;
     }
     public void setPros(Set<ProEmp> pros) {
         this.pros = pros;
     }
     public void setProid(Integer proid) {
         this.proid = proid;
     }
     public String getProname() {
         return proname;
     }
     public void setProname(String proname) {
         this.proname = proname;
     }
 }

Project.java

 <?xml version="1.0"?>
 <!DOCTYPE hibernate-mapping PUBLIC
         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
         <hibernate-mapping package="cn.happy.entity">

         <class name="Project" table="PROJECT">
         <id name="proid" column="PROID">
          <generator class="sequence">
          <param name="sequence">STU_SID</param>
          </generator>
         </id>
         <property name="proname" type="string" column="PRONAME"></property>
         <set name="employeses" table="PROEMP" cascade="save-update">
         <key column="RPROID"></key>
         <many-to-many class="Employee" column="REMPID"></many-to-many>
         </set>
         </class>

         </hibernate-mapping> 

Project.hbm.xml

中间关系表

 package cn.happy.entitys;

 public class ProEmp {
     private Integer id;
     private Project pro;
     private Employee emp;

     public Integer getId() {
         return id;
     }

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

     public Project getPro() {
         return pro;
     }

     public void setPro(Project pro) {
         this.pro = pro;
     }

     public Employee getEmp() {
         return emp;
     }

     public void setEmp(Employee emp) {
         this.emp = emp;
     }
 }

ProEmp.java

 <?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>
         <!-- Database connection settings -->
         <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>
         <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
         <property name="connection.username">hmy</property>
         <property name="connection.password">hmy</property>

         <!-- SQL dialect SQL方言-->
         <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>

         <!-- Echo all executed SQL to stdout 控制台显示-->
         <property name="show_sql">true</property>
         <!-- Enable Hibernate's automatic session context management -->
         <property name="current_session_context_class">thread</property>
         <!-- 是否格式化 -->
         <property name="format_sql">true</property>

         <!-- Drop and re-create the database schema on startup -->
         <property name="hbm2ddl.auto">create</property>

         <!-- <mapping resource="cn/happy/entity/Student.hbm.xml" /> -->
         <!-- <mapping resource="cn/happy/entity/grade.hbm.xml" /> -->
         <!-- <mapping class="cn.happy.entity.Grade"/> -->
         <!-- <mapping resource="cn/happy/entity/Dept.hbm.xml" />
         <mapping resource="cn/happy/entity/Emp.hbm.xml" /> -->
         <mapping resource="cn/happy/entity/Employee.hbm.xml" />
         <mapping resource="cn/happy/entity/Project.hbm.xml" /> 

         <!-- <mapping resource="cn/happy/entitys/Employee.hbm.xml" />
         <mapping resource="cn/happy/entitys/Project.hbm.xml" />
         <mapping resource="cn/happy/entitys/ProEmp.hbm.xml" /> -->

     </session-factory>

 </hibernate-configuration>

hibernate.hbm.xml

 package cn.happy.ui;

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

 import cn.happy.entity.Employee;
 import cn.happy.entity.Project;
 import cn.happy.util.HibernateUtil;

 public class Test3 {
     public static void main(String[] args) {
         select();
     }

     /**
      * 检索
      * */
     public static void select(){
         Session session = HibernateUtil.currentSession();
         Project pro = (Project)session.load(Project.class, 1);
         for (Employee item : pro.getEmployeses()) {
             System.out.println("员工："+item.getEmpname()+"\t参加的项目:");
             for (Project project : item.getProjects()) {
                 System.out.println(project.getProname());
             }
         }
         HibernateUtil.closeSession();
     }

     /**
      * 添加
      * */
     public static void one(){
         Session session = HibernateUtil.currentSession();
         Transaction tx = session.beginTransaction();

         Project pro=new Project();
         pro.setProname("ADO");

         Employee emp=new Employee();
         emp.setEmpname("范子阳");
         Employee emp2=new Employee();
         emp2.setEmpname("李夏鹏");

         pro.getEmployeses().add(emp);
         pro.getEmployeses().add(emp2);

         //未声明级联
         //emp.getProjects().add(pro);
         //emp2.getProjects().add(pro);

         session.save(pro);

         tx.commit();
         HibernateUtil.closeSession();
     }
 }

测试类

2.建立多对多双向关联 拆成两个一对多

 package cn.happy.entitys;

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

 public class Employee {
     private Integer empid;
     private String empname;
     private Set<ProEmp> emps = new HashSet<ProEmp>();

     public Set<ProEmp> getEmps() {
         return emps;
     }

     public void setEmps(Set<ProEmp> emps) {
         this.emps = emps;
     }

     public Integer getEmpid() {
         return empid;
     }

     public void setEmpid(Integer empid) {
         this.empid = empid;
     }

     public String getEmpname() {
         return empname;
     }

     public void setEmpname(String empname) {
         this.empname = empname;
     }

     public Set<ProEmp> getProjects() {
         return projects;
     }

     public void setProjects(Set<ProEmp> projects) {
         this.projects = projects;
     }

     private Set<ProEmp> projects = new HashSet<ProEmp>();
 }

Employee.java

 <?xml version="1.0"?>
 <!DOCTYPE hibernate-mapping PUBLIC
         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
         <hibernate-mapping package="cn.happy.entitys">

         <class name="Employee" table="EMPLOYEE">
         <id name="empid" column="EMPID">
          <generator class="sequence">
          <param name="sequence">STU_SID</param>
          </generator>
         </id>

         </class>

         </hibernate-mapping> 

Employee.hbm.xml

 package cn.happy.entitys;

 import java.util.Set;

 public class Project {
     private Integer proid;
     private String proname;
     private Set<ProEmp> pros;//为中间关系表所对应的实体类的类型
     public Integer getProid() {
         return proid;
     }
     public Set<ProEmp> getPros() {
         return pros;
     }
     public void setPros(Set<ProEmp> pros) {
         this.pros = pros;
     }
     public void setProid(Integer proid) {
         this.proid = proid;
     }
     public String getProname() {
         return proname;
     }
     public void setProname(String proname) {
         this.proname = proname;
     }
 }

Project.java

 <?xml version="1.0"?>
 <!DOCTYPE hibernate-mapping PUBLIC
         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
         <hibernate-mapping package="cn.happy.entitys">

         <class name="Project" table="PROJECT">
         <id name="proid" column="PROID">
          <generator class="sequence">
          <param name="sequence">STU_SID</param>
          </generator>
         </id>
         <property name="proname" type="string" column="PRONAME"></property>

         </class>

         </hibernate-mapping> 

Project.hbm.xml

 package cn.happy.entitys;

 public class ProEmp {
     private Integer id;
     private Project pro;
     private Employee emp;

     public Integer getId() {
         return id;
     }

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

     public Project getPro() {
         return pro;
     }

     public void setPro(Project pro) {
         this.pro = pro;
     }

     public Employee getEmp() {
         return emp;
     }

     public void setEmp(Employee emp) {
         this.emp = emp;
     }
 }

ProEmp.java

 <?xml version="1.0"?>
 <!DOCTYPE hibernate-mapping PUBLIC
         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
         <hibernate-mapping package="cn.happy.entitys">

         <class name="ProEmp" table="PROEMP">
         <id name="id" column="ID">
          <generator class="sequence">
          <param name="sequence">STU_SID</param>
          </generator>
         </id>

         <many-to-one name="emp" class="Employee" column="empid"></many-to-one>
         <many-to-one name="pro" class="Project" column="proid"></many-to-one>
         </class>

         </hibernate-mapping> 

ProEmp.hbm.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>
         <!-- Database connection settings -->
         <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>
         <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
         <property name="connection.username">hmy</property>
         <property name="connection.password">hmy</property>

         <!-- SQL dialect SQL方言-->
         <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>

         <!-- Echo all executed SQL to stdout 控制台显示-->
         <property name="show_sql">true</property>
         <!-- Enable Hibernate's automatic session context management -->
         <property name="current_session_context_class">thread</property>
         <!-- 是否格式化 -->
         <property name="format_sql">true</property>

         <!-- Drop and re-create the database schema on startup -->
         <property name="hbm2ddl.auto">create</property>

         <!-- <mapping resource="cn/happy/entity/Student.hbm.xml" /> -->
         <!-- <mapping resource="cn/happy/entity/grade.hbm.xml" /> -->
         <!-- <mapping class="cn.happy.entity.Grade"/> -->
         <!-- <mapping resource="cn/happy/entity/Dept.hbm.xml" />
         <mapping resource="cn/happy/entity/Emp.hbm.xml" /> -->
         <!-- <mapping resource="cn/happy/entity/Employee.hbm.xml" />
         <mapping resource="cn/happy/entity/Project.hbm.xml" />  -->

         <mapping resource="cn/happy/entitys/Employee.hbm.xml" />
         <mapping resource="cn/happy/entitys/Project.hbm.xml" />
         <mapping resource="cn/happy/entitys/ProEmp.hbm.xml" />

     </session-factory>

 </hibernate-configuration>

Hinernate.hbm.xml

 package cn.happy.ui;

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

 import cn.happy.entitys.Employee;
 import cn.happy.entitys.ProEmp;
 import cn.happy.entitys.Project;
 import cn.happy.util.HibernateUtil;

 public class Test4 {
     public static void main(String[] args) {
         test();
     }
     public static void test(){
         Session session = HibernateUtil.currentSession();
         Transaction tx = session.beginTransaction();

         Project pro=new Project();
         pro.setProname("ADO");

         Employee emp=new Employee();
         emp.setEmpname("范子阳");

         ProEmp proemp=new ProEmp();
         proemp.setEmp(emp);
         proemp.setPro(pro);

         session.save(proemp);
         session.save(emp);
         session.save(pro);

         tx.commit();
         HibernateUtil.closeSession();
     }

 }

测试类