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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

 1 package cn.happy.entitys;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 public class Employee {
 7     private Integer empid;
 8     private String empname;
 9     private Set<ProEmp> emps = new HashSet<ProEmp>();
10 
11     public Set<ProEmp> getEmps() {
12         return emps;
13     }
14 
15     public void setEmps(Set<ProEmp> emps) {
16         this.emps = emps;
17     }
18 
19     public Integer getEmpid() {
20         return empid;
21     }
22 
23     public void setEmpid(Integer empid) {
24         this.empid = empid;
25     }
26 
27     public String getEmpname() {
28         return empname;
29     }
30 
31     public void setEmpname(String empname) {
32         this.empname = empname;
33     }
34 
35     public Set<ProEmp> getProjects() {
36         return projects;
37     }
38 
39     public void setProjects(Set<ProEmp> projects) {
40         this.projects = projects;
41     }
42 
43     private Set<ProEmp> projects = new HashSet<ProEmp>();
44 }

Employee.java

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC
 3         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 5         <hibernate-mapping package="cn.happy.entitys">
 6         
 7         <class name="Employee" table="EMPLOYEE">
 8         <id name="empid" column="EMPID">
 9          <generator class="sequence">
10          <param name="sequence">STU_SID</param>
11          </generator>
12         </id>
13         <property name="empname" type="string" column="EMPNAME"></property>
14         
15         <set name="projects" table="PROEMP" cascade="save-update">
16         <key column="REMPID"></key>
17         <many-to-many class="Project" column="RPROID"></many-to-many>
18         </set>
19         
20         </class>
21         
22         </hibernate-mapping>

Employee.hbm.xml

 1 package cn.happy.entitys;
 2 
 3 import java.util.Set;
 4 
 5 public class Project {
 6     private Integer proid;
 7     private String proname;
 8     private Set<ProEmp> pros;
 9     public Integer getProid() {
10         return proid;
11     }
12     public Set<ProEmp> getPros() {
13         return pros;
14     }
15     public void setPros(Set<ProEmp> pros) {
16         this.pros = pros;
17     }
18     public void setProid(Integer proid) {
19         this.proid = proid;
20     }
21     public String getProname() {
22         return proname;
23     }
24     public void setProname(String proname) {
25         this.proname = proname;
26     }
27 }

Project.java

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC
 3         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 5         <hibernate-mapping package="cn.happy.entity">
 6         
 7         <class name="Project" table="PROJECT">
 8         <id name="proid" column="PROID">
 9          <generator class="sequence">
10          <param name="sequence">STU_SID</param>
11          </generator>
12         </id>
13         <property name="proname" type="string" column="PRONAME"></property>
14         <set name="employeses" table="PROEMP" cascade="save-update">
15         <key column="RPROID"></key>
16         <many-to-many class="Employee" column="REMPID"></many-to-many>
17         </set>
18         </class>
19         
20         </hibernate-mapping>

Project.hbm.xml

中间关系表

 1 package cn.happy.entitys;
 2 
 3 public class ProEmp {
 4     private Integer id;
 5     private Project pro;
 6     private Employee emp;
 7 
 8     public Integer getId() {
 9         return id;
10     }
11 
12     public void setId(Integer id) {
13         this.id = id;
14     }
15 
16     public Project getPro() {
17         return pro;
18     }
19 
20     public void setPro(Project pro) {
21         this.pro = pro;
22     }
23 
24     public Employee getEmp() {
25         return emp;
26     }
27 
28     public void setEmp(Employee emp) {
29         this.emp = emp;
30     }
31 }

ProEmp.java

 1 <?xml version='1.0' encoding='utf-8'?>
 2 <!DOCTYPE hibernate-configuration PUBLIC
 3         "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
 4         "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
 5 
 6 <hibernate-configuration>
 7 
 8     <session-factory>
 9         <!-- Database connection settings -->
10         <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>
11         <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
12         <property name="connection.username">hmy</property>
13         <property name="connection.password">hmy</property>
14 
15         <!-- SQL dialect SQL方言-->
16         <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
17 
18         <!-- Echo all executed SQL to stdout 控制台显示-->
19         <property name="show_sql">true</property>
20         <!-- Enable Hibernate's automatic session context management -->
21         <property name="current_session_context_class">thread</property>
22         <!-- 是否格式化 -->
23         <property name="format_sql">true</property>
24         
25         <!-- Drop and re-create the database schema on startup -->
26         <property name="hbm2ddl.auto">create</property>
27 
28         <!-- <mapping resource="cn/happy/entity/Student.hbm.xml" /> -->
29         <!-- <mapping resource="cn/happy/entity/grade.hbm.xml" /> -->
30         <!-- <mapping class="cn.happy.entity.Grade"/> -->
31         <!-- <mapping resource="cn/happy/entity/Dept.hbm.xml" />
32         <mapping resource="cn/happy/entity/Emp.hbm.xml" /> -->
33         <mapping resource="cn/happy/entity/Employee.hbm.xml" />
34         <mapping resource="cn/happy/entity/Project.hbm.xml" /> 
35         
36         <!-- <mapping resource="cn/happy/entitys/Employee.hbm.xml" />
37         <mapping resource="cn/happy/entitys/Project.hbm.xml" />
38         <mapping resource="cn/happy/entitys/ProEmp.hbm.xml" /> -->
39 
40     </session-factory>
41 
42 </hibernate-configuration>

hibernate.hbm.xml

 1 package cn.happy.ui;
 2 
 3 import org.hibernate.Session;
 4 import org.hibernate.Transaction;
 5 
 6 import cn.happy.entity.Employee;
 7 import cn.happy.entity.Project;
 8 import cn.happy.util.HibernateUtil;
 9 
10 public class Test3 {
11     public static void main(String[] args) {
12         select();
13     }
14     
15     /**
16      * 检索
17      * */
18     public static void select(){
19         Session session = HibernateUtil.currentSession();
20         Project pro = (Project)session.load(Project.class, 1);
21         for (Employee item : pro.getEmployeses()) {
22             System.out.println("员工："+item.getEmpname()+"	参加的项目:");
23             for (Project project : item.getProjects()) {
24                 System.out.println(project.getProname());
25             }
26         }
27         HibernateUtil.closeSession();
28     }
29     
30     /**
31      * 添加
32      * */
33     public static void one(){
34         Session session = HibernateUtil.currentSession();
35         Transaction tx = session.beginTransaction();
36         
37         Project pro=new Project();
38         pro.setProname("ADO");
39         
40         Employee emp=new Employee();
41         emp.setEmpname("范子阳");
42         Employee emp2=new Employee();
43         emp2.setEmpname("李夏鹏");
44         
45         pro.getEmployeses().add(emp);
46         pro.getEmployeses().add(emp2);
47         
48         //未声明级联
49         //emp.getProjects().add(pro);
50         //emp2.getProjects().add(pro);
51         
52         session.save(pro);
53 
54         tx.commit();
55         HibernateUtil.closeSession();
56     }
57 }

测试类

2.建立多对多双向关联拆成两个一对多

 1 package cn.happy.entitys;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 public class Employee {
 7     private Integer empid;
 8     private String empname;
 9     private Set<ProEmp> emps = new HashSet<ProEmp>();
10 
11     public Set<ProEmp> getEmps() {
12         return emps;
13     }
14 
15     public void setEmps(Set<ProEmp> emps) {
16         this.emps = emps;
17     }
18 
19     public Integer getEmpid() {
20         return empid;
21     }
22 
23     public void setEmpid(Integer empid) {
24         this.empid = empid;
25     }
26 
27     public String getEmpname() {
28         return empname;
29     }
30 
31     public void setEmpname(String empname) {
32         this.empname = empname;
33     }
34 
35     public Set<ProEmp> getProjects() {
36         return projects;
37     }
38 
39     public void setProjects(Set<ProEmp> projects) {
40         this.projects = projects;
41     }
42 
43     private Set<ProEmp> projects = new HashSet<ProEmp>();
44 }

Employee.java

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC
 3         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 5         <hibernate-mapping package="cn.happy.entitys">
 6         
 7         <class name="Employee" table="EMPLOYEE">
 8         <id name="empid" column="EMPID">
 9          <generator class="sequence">
10          <param name="sequence">STU_SID</param>
11          </generator>
12         </id>
13        
14         
15         </class>
16         
17         </hibernate-mapping>

Employee.hbm.xml

 1 package cn.happy.entitys;
 2 
 3 import java.util.Set;
 4 
 5 public class Project {
 6     private Integer proid;
 7     private String proname;
 8     private Set<ProEmp> pros;//为中间关系表所对应的实体类的类型
 9     public Integer getProid() {
10         return proid;
11     }
12     public Set<ProEmp> getPros() {
13         return pros;
14     }
15     public void setPros(Set<ProEmp> pros) {
16         this.pros = pros;
17     }
18     public void setProid(Integer proid) {
19         this.proid = proid;
20     }
21     public String getProname() {
22         return proname;
23     }
24     public void setProname(String proname) {
25         this.proname = proname;
26     }
27 }

Project.java

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC
 3         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 5         <hibernate-mapping package="cn.happy.entitys">
 6         
 7         <class name="Project" table="PROJECT">
 8         <id name="proid" column="PROID">
 9          <generator class="sequence">
10          <param name="sequence">STU_SID</param>
11          </generator>
12         </id>
13         <property name="proname" type="string" column="PRONAME"></property>
14         
15         </class>
16         
17         </hibernate-mapping>

Project.hbm.xml

 1 package cn.happy.entitys;
 2 
 3 public class ProEmp {
 4     private Integer id;
 5     private Project pro;
 6     private Employee emp;
 7 
 8     public Integer getId() {
 9         return id;
10     }
11 
12     public void setId(Integer id) {
13         this.id = id;
14     }
15 
16     public Project getPro() {
17         return pro;
18     }
19 
20     public void setPro(Project pro) {
21         this.pro = pro;
22     }
23 
24     public Employee getEmp() {
25         return emp;
26     }
27 
28     public void setEmp(Employee emp) {
29         this.emp = emp;
30     }
31 }

ProEmp.java

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC
 3         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4         "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 5         <hibernate-mapping package="cn.happy.entitys">
 6         
 7         <class name="ProEmp" table="PROEMP">
 8         <id name="id" column="ID">
 9          <generator class="sequence">
10          <param name="sequence">STU_SID</param>
11          </generator>
12         </id>
13         
14         <many-to-one name="emp" class="Employee" column="empid"></many-to-one>
15         <many-to-one name="pro" class="Project" column="proid"></many-to-one>
16         </class>
17         
18         </hibernate-mapping>

ProEmp.hbm.xml

 1 <?xml version='1.0' encoding='utf-8'?>
 2 <!DOCTYPE hibernate-configuration PUBLIC
 3         "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
 4         "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
 5 
 6 <hibernate-configuration>
 7 
 8     <session-factory>
 9         <!-- Database connection settings -->
10         <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>
11         <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
12         <property name="connection.username">hmy</property>
13         <property name="connection.password">hmy</property>
14 
15         <!-- SQL dialect SQL方言-->
16         <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
17 
18         <!-- Echo all executed SQL to stdout 控制台显示-->
19         <property name="show_sql">true</property>
20         <!-- Enable Hibernate's automatic session context management -->
21         <property name="current_session_context_class">thread</property>
22         <!-- 是否格式化 -->
23         <property name="format_sql">true</property>
24         
25         <!-- Drop and re-create the database schema on startup -->
26         <property name="hbm2ddl.auto">create</property>
27 
28         <!-- <mapping resource="cn/happy/entity/Student.hbm.xml" /> -->
29         <!-- <mapping resource="cn/happy/entity/grade.hbm.xml" /> -->
30         <!-- <mapping class="cn.happy.entity.Grade"/> -->
31         <!-- <mapping resource="cn/happy/entity/Dept.hbm.xml" />
32         <mapping resource="cn/happy/entity/Emp.hbm.xml" /> -->
33         <!-- <mapping resource="cn/happy/entity/Employee.hbm.xml" />
34         <mapping resource="cn/happy/entity/Project.hbm.xml" />  -->
35         
36         <mapping resource="cn/happy/entitys/Employee.hbm.xml" />
37         <mapping resource="cn/happy/entitys/Project.hbm.xml" />
38         <mapping resource="cn/happy/entitys/ProEmp.hbm.xml" />
39 
40     </session-factory>
41 
42 </hibernate-configuration>

Hinernate.hbm.xml

 1 package cn.happy.ui;
 2 
 3 import org.hibernate.Session;
 4 import org.hibernate.Transaction;
 5 
 6 import cn.happy.entitys.Employee;
 7 import cn.happy.entitys.ProEmp;
 8 import cn.happy.entitys.Project;
 9 import cn.happy.util.HibernateUtil;
10 
11 public class Test4 {
12     public static void main(String[] args) {
13         test();
14     }
15     public static void test(){
16         Session session = HibernateUtil.currentSession();
17         Transaction tx = session.beginTransaction();
18         
19         Project pro=new Project();
20         pro.setProname("ADO");
21         
22         Employee emp=new Employee();
23         emp.setEmpname("范子阳");
24         
25         ProEmp proemp=new ProEmp();
26         proemp.setEmp(emp);
27         proemp.setPro(pro);
28         
29         session.save(proemp);
30         session.save(emp);
31         session.save(pro);
32 
33         tx.commit();
34         HibernateUtil.closeSession();
35     }
36     
37 }

测试类

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原文地址：https://www.cnblogs.com/hmy-1365/p/5768300.html