多对多关联映射
hibernate多对多关联映射(单向User---->Role)
具体映射方式：
hibernate多对多关联映射(双向User<---->Role)
映射方法：
<key>中column属性值要与单向关联中的<many-to-many>标签中的column属性值一致
在<many-to-many>中的column属性值要与单向关联中<key>标签的column属性值一致
具体映射方式：
<set name="roles" table="t_user_role"> <key column="userid"/> <many-to-many class="com.bjsxt.hibernate.Role" column="roleid"/> </set>
import java.util.Set;
public class User {
private int id;
private String name;
private Set<Role> roles;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void setRoles(Set<Role> roles) {
this.roles = roles;
}
public Set<Role> getRoles() {
return roles;
}
}
public class Role {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
//Role.hbm.xml <hibernate-mapping> <class name="com.bjsxt.hibernate.Role" table="t_role"> <id name="id"> <generator class="native"/> </id> <property name="name" length = "10"/> </class> </hibernate-mapping> //User.hbm.xml <hibernate-mapping> <class name="com.bjsxt.hibernate.User" table="t_user"> <id name="id"> <generator class="native"/> </id> <property name="name" length = "10"/> <set name="roles" table="t_user_role"><!-- Set标签映射Set集合 --> <key column="userid"/><!-- 生成第三方表，userid作为外键指向user --> <many-to-many class="com.bjsxt.hibernate.Role" column="roleid"/> <!-- roleid作为外键指向Role --> </set> </class> </hibernate-mapping>
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.hibernate.Session;
import junit.framework.TestCase;
public class Many2Many extends TestCase {
public void testSave2() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Role r1 = new Role();
r1.setName("数据录入人员");
session.save(r1);
Role r2 = new Role();
r2.setName("商务主管");
session.save(r2);
Role r3 = new Role();
r3.setName("大区经理");
session.save(r3);
User u1 = new User();
u1.setName("10");
Set<Role> u1Roles = new HashSet<Role>();
u1Roles.add(r1);
u1Roles.add(r2);
u1.setRoles(u1Roles);
User u2 = new User();
u2.setName("祖儿");
Set<Role> u2Roles = new HashSet<Role>();
u2Roles.add(r2);
u2Roles.add(r3);
u2.setRoles(u2Roles);
User u3 = new User();
u3.setName("杰伦");
Set<Role> u3Roles = new HashSet<Role>();
u3Roles.add(r1);
u3Roles.add(r2);
u3Roles.add(r3);
u3.setRoles(u3Roles);
session.save(u1);
session.save(u2);
session.save(u3);
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
public void testLoad1() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
User user = (User)session.load(User.class, 4); //根据主键加载用户
System.out.println(user.getName());
for (Iterator<Role> iter=user.getRoles().iterator(); iter.hasNext();) {
Role role = iter.next(); // 根据用户获得其角色
System.out.println(role.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
}
hibernate多对多关联映射(双向User<---->Role)
映射方法：
<set name="roles" table="t_user_role"> <key column="userid"/> <many-to-many class="com.bjsxt.hibernate.Role" column="roleid"/> </set>table属性值必须和单向关联中的table属性值一致
<key>中column属性值要与单向关联中的<many-to-many>标签中的column属性值一致
在<many-to-many>中的column属性值要与单向关联中<key>标签的column属性值一致
import java.util.Set;
public class User {
private int id;
private String name;
private Set<Role> roles;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void setRoles(Set<Role> roles) {
this.roles = roles;
}
public Set<Role> getRoles() {
return roles;
}
}
import java.util.Set;
public class Role {
private int id;
private String name;
private Set<User> users;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void setUsers(Set<User> users) {
this.users = users;
}
public Set<User> getUsers() {
return users;
}
}
//Role.hbm.xml <hibernate-mapping> <class name="com.bjsxt.hibernate.Role" table="t_role"> <id name="id"> <generator class="native"/> </id> <property name="name" length = "10"/> <set name="users" table="t_user_role" order-by="userid"><!-- 第三方表要一 致--> <key column="roleid"/><!-- roleid作为外键指向Role --> <many-to-many class="com.bjsxt.hibernate.User" column="userid"/> <!-- userid作为外键指向user --> </set> </class> </hibernate-mapping> //User.hbm.xml <hibernate-mapping> <class name="com.bjsxt.hibernate.User" table="t_user"> <id name="id"> <generator class="native"/> </id> <property name="name" length = "10"/> <set name="roles" table="t_user_role"><!-- Set标签映射Set集合 --> <key column="userid"/><!-- 生成第三方表，userid作为外键指向user --> <many-to-many class="com.bjsxt.hibernate.Role" column="roleid"/> <!-- roleid作为外键指向Role --> </set> </class> </hibernate-mapping>
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.hibernate.Session;
import junit.framework.TestCase;
public class Many2Many extends TestCase {
public void testSave2() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Role r1 = new Role();
r1.setName("数据录入人员");
session.save(r1);
Role r2 = new Role();
r2.setName("商务主管");
session.save(r2);
Role r3 = new Role();
r3.setName("大区经理");
session.save(r3);
User u1 = new User();
u1.setName("10");
Set<Role> u1Roles = new HashSet<Role>();
u1Roles.add(r1);
u1Roles.add(r2);
u1.setRoles(u1Roles);
User u2 = new User();
u2.setName("祖儿");
Set<Role> u2Roles = new HashSet<Role>();
u2Roles.add(r2);
u2Roles.add(r3);
u2.setRoles(u2Roles);
User u3 = new User();
u3.setName("杰伦");
Set<Role> u3Roles = new HashSet<Role>();
u3Roles.add(r1);
u3Roles.add(r2);
u3Roles.add(r3);
u3.setRoles(u3Roles);
session.save(u1);
session.save(u2);
session.save(u3);
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
public void testLoad1() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
User user = (User)session.load(User.class, 4); //根据主键加载用户
System.out.println(user.getName());
for (Iterator<Role> iter=user.getRoles().iterator(); iter.hasNext();) {
Role role = iter.next(); // 根据用户获得其角色
System.out.println(role.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
public void testLoad2() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Role role = (Role)session.load(Role.class, 1); // 加载角色
System.out.println(role.getName());
for (Iterator<User> iter=role.getUsers().iterator(); iter.hasNext();) {
User user = iter.next(); // 根据角色加载用户
System.out.println(user.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
}