详解hibernate双向多对多关联映射XML与注解版

package Hibernate_demo1.Demo15.Entity;  import java.util.Set;  public class Role {      private String id;   private String rame;   private Set<User> users;         public String getId() {     return id;   }   public void setId(String id) {     this.id = id;   }   public String getRame() {     return rame;   }   public void setRame(String rame) {     this.rame = rame;   }   public Set<User> getUsers() {     return users;   }   public void setUsers(Set<User> users) {     this.users = users;   } } 

package Hibernate_demo1.Demo15.Entity;  import java.util.Set;  public class User {    private String id;   private String uname;   private Set<Role> roles;        public String getId() {     return id;   }   public void setId(String id) {     this.id = id;   }   public String getUname() {     return uname;   }   public void setUname(String uname) {     this.uname = uname;   }   public Set<Role> getRoles() {     return roles;   }   public void setRoles(Set<Role> roles) {     this.roles = roles;   }       } 

<?xml version="1.0"?>  <!DOCTYPE hibernate-mapping PUBLIC     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  <hibernate-mapping>    <class name="Hibernate_demo1.Demo15.Entity.Role" table="role">      <id name="id" type="java.lang.String">        <column name="id"/>       <generator class="uuid">        </generator>      </id>      <property name="rame" column="rname"/>          <set name="users" table="user_role">        <key column="roleid"></key>        <many-to-many class="Hibernate_demo1.Demo15.Entity.User" column="userid"></many-to-many>      </set>    </class>  </hibernate-mapping>  

<?xml version="1.0"?>  <!DOCTYPE hibernate-mapping PUBLIC     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  <hibernate-mapping>    <class name="Hibernate_demo1.Demo15.Entity.User" table="user">      <id name="id">        <generator class="uuid">        </generator>      </id>           <property name="uname" column="uname"/>             <set name="roles" table="user_role">       <key column="userid"/>       <many-to-many class="Hibernate_demo1.Demo15.Entity.Role" column="roleid" />       </set>   </class>  </hibernate-mapping>  

package Hibernate_demo1.Demo15;  import java.util.HashSet; import java.util.Set;  import org.hibernate.Session;  import Hibernate_demo1.Demo15.Entity.Role; import Hibernate_demo1.Demo15.Entity.User; import Hibernate_demo1.Demo15.Util.HibernateUtils;    public class App  {   public static void main( String[] args )   {          Session session = null;     try{                session = HibernateUtils.getSession();       session.beginTransaction();                Role r1 = new Role();       r1.setRame("数据录入人员");       session.save(r1);              Role r2 = new Role();       r2.setRame("商务主管");       session.save(r2);              Role r3 = new Role();       r3.setRame("商务经理");       session.save(r3);              Role r4 = new Role();       r4.setRame("项目会计");       session.save(r4);              User u1 = new User();       u1.setUname("张三");       Set<Role> u1Roles = new HashSet<Role>();       u1Roles.add(r1);       u1Roles.add(r2);       u1.setRoles(u1Roles);       session.save(u1);              User u2 = new User();       u2.setUname("李四");       Set<Role> u2Roles = new HashSet<Role>();       u2Roles.add(r1);       u2Roles.add(r2);       u2Roles.add(r3);       u2.setRoles(u2Roles);       session.save(u2);              User u3 = new User();       u3.setUname("王五");       Set<Role> u3Roles = new HashSet<Role>();       u3Roles.add(r3);       u3Roles.add(r4);       u3.setRoles(u3Roles);       session.save(u3);                     session.getTransaction().commit();      }catch(Exception e){        e.printStackTrace();        session.getTransaction().rollback();      }finally{        HibernateUtils.closeSession(session);      }   } } 

Hibernate:    insert    into     role     (rname, id)    values     (?, ?) Hibernate:    insert    into     role     (rname, id)    values     (?, ?) Hibernate:    insert    into     role     (rname, id)    values     (?, ?) Hibernate:    insert    into     role     (rname, id)    values     (?, ?) Hibernate:    insert    into     user     (uname, id)    values     (?, ?) Hibernate:    insert    into     user     (uname, id)    values     (?, ?) Hibernate:    insert    into     user     (uname, id)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) 

package Hibernate_demo1.Demo16.Entity;  import java.util.HashSet; import java.util.Set;  import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.ManyToMany; import javax.persistence.Table;  import org.hibernate.annotations.GenericGenerator;  @Entity @Table(name="role") public class Role {      @Id     @GenericGenerator(name="uuidGenerator", strategy="uuid")     @GeneratedValue(generator="uuidGenerator")   private String id;      @Column(name="rname")   private String rame;      @ManyToMany(cascade=CascadeType.REFRESH,mappedBy="roles")   private Set<User> users=new HashSet<User>();               public String getId() {     return id;   }   public void setId(String id) {     this.id = id;   }   public String getRame() {     return rame;   }   public void setRame(String rame) {     this.rame = rame;   }   public Set<User> getUsers() {     return users;   }   public void setUsers(Set<User> users) {     this.users = users;   } } 

package Hibernate_demo1.Demo16.Entity;  import java.util.HashSet; import java.util.Set;  import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.JoinTable; import javax.persistence.ManyToMany; import javax.persistence.Table; import javax.persistence.JoinColumn;  import org.hibernate.annotations.GenericGenerator;  @Entity @Table(name="user") public class User {    @Id     @GenericGenerator(name="uuidGenerator", strategy="uuid")     @GeneratedValue(generator="uuidGenerator")   private String id;      @Column(name="uname")   private String uname;      /*    * @ManyToMany表示多对多关联，对于这种关联极少数情况会使用级联删除，我这里设置的是级联刷新；    * 因为有中间表的存在这里使用@JoinTable来设置关联表后面的name配置的是关联表的名称    * inverseJoinColumn配置的是关系被维护一方主键对应的中间表字段    * joinColumn配置的是关系维护方主键对应的中间表字段。    */   @ManyToMany(cascade=CascadeType.REFRESH)   @JoinTable(name="user_role",inverseJoinColumns=@JoinColumn(name="roleid"),joinColumns=@JoinColumn(name="userid"))   private Set<Role> roles=new HashSet<Role>();        public String getId() {     return id;   }   public void setId(String id) {     this.id = id;   }   public String getUname() {     return uname;   }   public void setUname(String uname) {     this.uname = uname;   }   public Set<Role> getRoles() {     return roles;   }   public void setRoles(Set<Role> roles) {     this.roles = roles;   }       } 

package Hibernate_demo1.Demo16;  import java.util.HashSet; import java.util.Set;  import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.cfg.Configuration;  import Hibernate_demo1.Demo16.Entity.Role; import Hibernate_demo1.Demo16.Entity.User;   public class Test {    public static void main(String[] args) {           SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();      Session session = sessionFactory.getCurrentSession();      Transaction tx = session.beginTransaction();              //创建两个用户     User us1=new User();     us1.setUname("小明");          User us2=new User();     us2.setUname("小黑");          //创建用户集合     Set<User> su=new HashSet<User>();     su.add(us1);     su.add(us2);               //创建两个角色     Role ro1=new Role();     ro1.setRame("程序员");     ro1.setUsers(su);          Role ro2=new Role();     ro2.setRame("技术经理");     ro2.setUsers(su);               //创建角色集合     Set<Role> sr=new HashSet<Role>();     sr.add(ro1);     sr.add(ro2);          //往用户添加角色集合     us1.setRoles(sr);     us2.setRoles(sr);          //保存用户和角色     session.save(us1);     session.save(us2);     session.save(ro1);     session.save(ro2);               tx.commit();     session.close();   }  } 

Hibernate:    insert    into     user     (uname, id)    values     (?, ?) Hibernate:    insert    into     user     (uname, id)    values     (?, ?) Hibernate:    insert    into     role     (rname, id)    values     (?, ?) Hibernate:    insert    into     role     (rname, id)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?) Hibernate:    insert    into     user_role     (userid, roleid)    values     (?, ?)