Hibernate多对多的关系

数据库和项目工程

实体类

Roles.java

package com.minde.po;import java.util.HashSet;import java.util.Set;public class Roles {private int roleid;private String rolename;private String memo;//一个角色有多个用户private Set<Userinfo> userinfos = new HashSet<>();public Set<Userinfo> getUserinfos() {return userinfos;}public void setUserinfos(Set<Userinfo> userinfos) {this.userinfos = userinfos;}public int getRoleid() {return roleid;}public void setRoleid(int roleid) {this.roleid = roleid;}public String getRolename() {return rolename;}public void setRolename(String rolename) {this.rolename = rolename;}public String getMemo() {return memo;}public void setMemo(String memo) {this.memo = memo;}public Roles(int roleid, String rolename, String memo) {super();this.roleid = roleid;this.rolename = rolename;this.memo = memo;}public Roles(String rolename, String memo) {super();this.rolename = rolename;this.memo = memo;}public Roles() {super();}@Overridepublic String toString() {return "Roles [roleid=" + roleid + ", rolename=" + rolename + ", memo=" + memo + "]";}}

Userinfo.java

package com.minde.po;import java.util.HashSet;import java.util.Set;public class Userinfo {private int userid;private String username;private String password;//一个用户有多个角色private Set<Roles> roles = new HashSet<>();public Set<Roles> getRoles() {return roles;}public void setRoles(Set<Roles> roles) {this.roles = roles;}public int getUserid() {return userid;}public void setUserid(int userid) {this.userid = userid;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public Userinfo(int userid, String username, String password) {super();this.userid = userid;this.username = username;this.password = password;}public Userinfo(String username, String password) {super();this.username = username;this.password = password;}public Userinfo() {super();}@Overridepublic String toString() {return "Userinfo [userid=" + userid + ", username=" + username + ", password=" + password + "]";}}

hbm.xml文件配置（关系映射）

Roles.hbm.xml

<!DOCTYPE hibernate-mapping PUBLIC     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.minde.po"><class name="Roles"><!-- 定义主键生成策略 --><id name="roleid"><generator class="sequence"><param name="sequence">roles_seq</param></generator></id><!-- 定义其它基本属性 --><property name="rolename"/><property name="memo"/><!-- 定义多对多关联关系映射 --><!-- table属性指示第三张表的表名 --><set name="userinfos" table="roles_userinfo" lazy="false" ><!-- <key>代表当前表roles在第三张表roles_userinfo中的外键 --><key column="rid"/><!-- 下面的column代表对方表userinfo在第三张表中的外键 --><many-to-many class="Userinfo" column="userid"/></set></class></hibernate-mapping>

首先该类的属性userinfos 所关联的表为roles_userinfo;key代表当前表roles在第三张表roles_userinfo的外键，而many-to-many 的class是代表对方的类，column代表对方表在第三张表中的外键

Userinfo.hbm.xml

<!DOCTYPE hibernate-mapping PUBLIC     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.minde.po"><class name="Userinfo"><!-- 定义主键生成策略 --><id name="userid"><generator class="sequence"><param name="sequence">sequence_userinfo</param></generator></id><!-- 定义其它基本属性 --><property name="username"/><property name="password"/><set name="roles" table="roles_userinfo"><key column="userid"/><many-to-many class="Roles" column="roleid"/></set></class></hibernate-mapping>

hibernate.cfg.xml文件配置

<!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><property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property><property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property><property name="hibernate.connection.username">scott</property><property name="hibernate.connection.password">tiger</property><property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property><property name="show_sql">true</property><mapping resource="com/minde/po/Userinfo.hbm.xml"/><mapping resource="com/minde/po/Roles.hbm.xml"/></session-factory></hibernate-configuration>

struts.XML文件配置

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"    "http://struts.apache.org/dtds/struts-2.3.dtd"><struts><!-- 配置常量以覆盖struts-default.xml文件的默认设置 --><constant name="struts.devMode" value="true"/><constant name="struts.enable.DynamicMethodInvocation" value="true"/><package name="struts" extends="struts-default"></package></struts>

Utils包的HibernateSessionFactory.java

package com.minde.utils;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;import org.hibernate.service.ServiceRegistry;import org.hibernate.service.ServiceRegistryBuilder;public class HibernateSessionFactory {/**引入sessionFactory*/private static SessionFactory sessionFactory;/**构造Configuration配置*/private static Configuration config = new Configuration();/**定义一个ThreadLocal对象用于存放session*/private static ThreadLocal<Session> threadLocal = new ThreadLocal<>();static {//1.读取hibernate.cfg.xmlconfig.configure();//2.构造ServiceRegistry对象ServiceRegistry sr = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();//3.生成一个sessionFactorysessionFactory = config.buildSessionFactory(sr);}//获取到session对象public static Session getSession(){Session session = threadLocal.get();if(null == session || !session.isOpen()){if(sessionFactory == null){rebuildSessionFactory();}session = (sessionFactory != null) ? sessionFactory.openSession() : null;//将session设置到threadLocal中threadLocal.set(session);}return session;}//重建sessionFactoryprivate static void rebuildSessionFactory() {config.configure();ServiceRegistry serviceRegistry = new ServiceRegistryBuilder()  .applySettings(config.getProperties())  .buildServiceRegistry();sessionFactory = config.buildSessionFactory(serviceRegistry );}//关闭sessionpublic static void closeSession(){Session session = threadLocal.get();threadLocal.set(null);if(session != null){session.close();}}}

dao层

IBaseDao.java

package com.minde.dao;import java.io.Serializable;import java.util.List;public interface IBaseDao {/** @param hql  查询所有*/public List findAll(String hql) ;/**@param obj 需要添加的对象 */public void save(Object obj);/** @param obj 需要修改的对象*/public void update(Object obj);/** 根据id查询对象 * @param clazz  要查找的对象类 * @param id  * @return */public Object findObjectById(Class clazz,Serializable id);/** @param obj 删除指定对象*/public void delete (Object obj);}

BaseDaoImpl.java

package com.minde.dao.impl;import java.io.Serializable;import java.util.List;import org.hibernate.Session;import org.hibernate.Transaction;import com.minde.dao.IBaseDao;import com.minde.utils.HibernateSessionFactory;public class BaseDaoImpl implements IBaseDao {@Overridepublic List findAll(String hql) {List list = null;Session session = HibernateSessionFactory.getSession();Transaction tx = null;try {//1.开始事务tx = session.beginTransaction();//2.执行命令list = session.createQuery(hql).list();//3.提交事务tx.commit();} catch (Exception e) {e.printStackTrace();//回滚事务tx.rollback();}finally{//关闭sessionHibernateSessionFactory.closeSession();}return list;}@Overridepublic void save(Object obj) {Session session = HibernateSessionFactory.getSession();Transaction tx = null;try {//1.开始事务tx = session.beginTransaction();//2.执行命令session.save(obj);//3.提交事务tx.commit();} catch (Exception e) {e.printStackTrace();//回滚事务tx.rollback();}finally{//关闭sessionHibernateSessionFactory.closeSession();}}@Overridepublic void update(Object obj) {Session session = HibernateSessionFactory.getSession();Transaction tx = null;try {//1.开始事务tx = session.beginTransaction();//2.执行命令session.merge(obj);//session.update(obj);//3.提交事务tx.commit();} catch (Exception e) {e.printStackTrace();//回滚事务tx.rollback();}finally{//关闭sessionHibernateSessionFactory.closeSession();}}@Overridepublic Object findObjectById(Class clazz, Serializable id) {Object obj = null;Session session = HibernateSessionFactory.getSession();Transaction tx = null;try {//1.开始事务tx = session.beginTransaction();//2.执行命令obj = session.get(clazz,id);//3.提交事务tx.commit();} catch (Exception e) {e.printStackTrace();//回滚事务tx.rollback();}finally{//关闭sessionHibernateSessionFactory.closeSession();}return obj;}@Overridepublic void delete(Object obj) {Session session = HibernateSessionFactory.getSession();Transaction tx = null;try {//1.开始事务tx = session.beginTransaction();//2.执行命令session.delete(obj);//3.提交事务tx.commit();} catch (Exception e) {e.printStackTrace();//回滚事务tx.rollback();}finally{//关闭sessionHibernateSessionFactory.closeSession();}}}

RolesAction.java

package com.minde.action;import java.util.ArrayList;import java.util.List;import javax.management.relation.Role;import org.apache.struts2.convention.annotation.Result;import org.apache.struts2.convention.annotation.ResultPath;import org.apache.struts2.convention.annotation.Results;import com.minde.dao.IBaseDao;import com.minde.dao.impl.BaseDaoImpl;import com.minde.po.Roles;import com.minde.po.Userinfo;import com.opensymphony.xwork2.ActionSupport;@SuppressWarnings("all")@Results({@Result(name="list",location="list.jsp"),  @Result(name="add",location="add.jsp"),  @Result(name="update",location="update.jsp"),  @Result(name="tolist",type="redirect",location="roles!list")})@ResultPath("/WEB-INF/roles/")public class RolesAction extends ActionSupport {private IBaseDao bd = new BaseDaoImpl();private List<Roles> roles ;private List<Integer> userids;//所有用户编号private List<Userinfo> userinfos;   //所有用户集合private Roles role;//代表当前正在操作的role对象public Roles getRole() {return role;}public void setRole(Roles role) {this.role = role;}public List<Userinfo> getUserinfos() {return userinfos;}public void setUserinfos(List<Userinfo> userinfos) {this.userinfos = userinfos;}public List<Integer> getUserids() {return userids;}public void setUserids(List<Integer> userids) {this.userids = userids;}//列表所有的角色public List<Roles> getRoles() {return roles;}public void setRoles(List<Roles> roles) {this.roles = roles;}//列表角色public String list() throws Exception{roles = bd.findAll("from Roles");return "list";}//到添加角色页面public String toadd() throws Exception{//思考：在添加角色时考虑是否选择此角色所关联的用户？（提供用户列表）//查询出所有用户集合userinfos = bd.findAll("from Userinfo");return "add";}//添加用户public String add() throws Exception{for(int id : userids){//1.根据用户编号查询出用户Userinfo user = (Userinfo) bd.findObjectById(Userinfo.class, id);//2.建立role对象和user对象间的关系role.getUserinfos().add(user);}bd.save(role);return "tolist";}//到修改页面public String toupdate() throws Exception{//1.根据roleid得到当前role对象role = (Roles) bd.findObjectById(Roles.class, role.getRoleid());//2.根据role对象查询出其关联的useriduserids = new ArrayList<>();for(Userinfo userinfo: role.getUserinfos()){userids.add(userinfo.getUserid());}//3.查询出用户集合userinfos = bd.findAll("from Userinfo");return "update";}//修改角色public String update() throws Exception{for(int id : userids){//1.根据用户编号查询出用户Userinfo user = (Userinfo) bd.findObjectById(Userinfo.class, id);//2.建立role对象和user对象间的关系（有主键才需要“你中有我，我中有你”,这里的第三张表中无主键）role.getUserinfos().add(user);}bd.update(role);return "tolist";}//删除角色public String delete() throws Exception{//1.根据roleid得到当前role对象role = (Roles) bd.findObjectById(Roles.class, role.getRoleid());//2.删除角色bd.delete(role);return "tolist";}}

JSP页面

list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>列表角色</title><script>function $(v){return document.getElementById(v);}function toggle(v){$('t_'+v).style.display = $('t_'+v).style.display == 'none' ? '' : 'none';}</script></head><body><h2>列表角色<hr></h2><table width=80% align=center border=4 rules="rows"><tr height=40 bgcolor="#efefef"><th>角色ID</th><th>角色名称</th><th>角色描述</th><th>操作</th></tr><s:iterator value="roles"><tr height=36 align=center bgcolor="lightblue" onclick="toggle(${roleid})"><td><s:property value="roleid"/></td><td><s:property value="rolename"/></td><td><s:property value="memo"/></td><td><s:a href="roles!toupdate?role.roleid=%{roleid}">修改</s:a><s:a href="roles!delete?role.roleid=%{roleid}" onclick="return confirm('你真的要删除吗？')">删除</s:a></td></tr><tr style="display:none" id="t_${roleid }"><td colspan=4><s:iterator value="userinfos"><div style="border:1px dotted blue;background:lightyellow">账号:<s:property value="userid"/><br>用户名：<s:property value="username"/><br>密码：<s:property value="password"/><br></div></s:iterator></td></tr></s:iterator><tr height=40 bgcolor="#efefef" align=right><td colspan=4><s:a href="roles!toadd">添加角色</s:a>明德学校版权所有2000-2017.</td></tr></table></body></html>

add.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>添加角色</title></head><body><h2>添加角色<hr></h2><s:form action="roles!add"><s:textfield name="role.rolename" label="角色名称"/><s:textfield name="role.memo" label="角色说明"/><!-- 所有的用户信息 --><s:checkboxlist list="userinfos" listKey="userid" listValue="username"    name="userids" label="请选择用户"/><s:submit value="添加角色"/></s:form></body></html>

update.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>修改角色</title></head><body><h2>修改角色<hr></h2><s:form action="roles!update"><s:hidden name="role.roleid"/><s:textfield name="role.rolename" label="角色名称"/><s:textfield name="role.memo" label="角色说明"/><!-- 所有的用户信息 --><s:checkboxlist list="userinfos" listKey="userid" listValue="username"    name="userids" label="请选择用户"/><s:submit value="修改角色" align="left"/></s:form></body></html>

web.xml文件配置

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">  <display-name>hibernate4_01</display-name>    <!-- 配置struts2过滤器 --><filter><filter-name>struts</filter-name><filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class></filter><filter-mapping><filter-name>struts</filter-name><url-pattern>/*</url-pattern></filter-mapping>  <welcome-file-list>    <welcome-file>index.html</welcome-file>    <welcome-file>index.htm</welcome-file>    <welcome-file>index.jsp</welcome-file>    <welcome-file>default.html</welcome-file>    <welcome-file>default.htm</welcome-file>    <welcome-file>default.jsp</welcome-file>  </welcome-file-list></web-app>