两个实体类: 客户与联系人, 一个客户可以有多个联系人
客户类:
- package domain;
- import java.util.HashSet;
- import java.util.Set;
- // 客户实体
- public class Customer {
- private Long cust_id;
- private String cust_name;
- private String cust_source;
- private String cust_industry;
- private String cust_level;
- private String cust_linkman;
- private String cust_phone;
- private String cust_mobile;
- // 使用 set 集合, 表达一对多关系
- private Set < LinkMan > linkMens = new HashSet < LinkMan > ();
- public Set < LinkMan > getLinkMens() {
- return linkMens;
- }
- public void setLinkMens(Set < LinkMan > linkMens) {
- this.linkMens = linkMens;
- }
- public Long getCust_id() {
- return cust_id;
- }
- public void setCust_id(Long cust_id) {
- this.cust_id = cust_id;
- }
- public String getCust_name() {
- return cust_name;
- }
- public void setCust_name(String cust_name) {
- this.cust_name = cust_name;
- }
- public String getCust_source() {
- return cust_source;
- }
- public void setCust_source(String cust_source) {
- this.cust_source = cust_source;
- }
- public String getCust_industry() {
- return cust_industry;
- }
- public void setCust_industry(String cust_industry) {
- this.cust_industry = cust_industry;
- }
- public String getCust_level() {
- return cust_level;
- }
- public void setCust_level(String cust_level) {
- this.cust_level = cust_level;
- }
- public String getCust_linkman() {
- return cust_linkman;
- }
- public void setCust_linkman(String cust_linkman) {
- this.cust_linkman = cust_linkman;
- }
- public String getCust_phone() {
- return cust_phone;
- }
- public void setCust_phone(String cust_phone) {
- this.cust_phone = cust_phone;
- }
- public String getCust_mobile() {
- return cust_mobile;
- }
- public void setCust_mobile(String cust_mobile) {
- this.cust_mobile = cust_mobile;
- }@Override public String toString() {
- return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + "]";
- }
- }
- View Code
联系人类:
- package domain;
- // 联系人实体
- public class LinkMan {
- private Long lkm_id;
- private Character lkm_gender;
- private String lkm_name;
- private String lkm_phone;
- private String lkm_email;
- private String lkm_qq;
- private String lkm_mobile;
- private String lkm_memo;
- private String lkm_position;
- // 表达多对一关系
- private Customer customer;
- public Customer getCustomer() {
- return customer;
- }
- public void setCustomer(Customer customer) {
- this.customer = customer;
- }
- public Long getLkm_id() {
- return lkm_id;
- }
- public void setLkm_id(Long lkm_id) {
- this.lkm_id = lkm_id;
- }
- public Character getLkm_gender() {
- return lkm_gender;
- }
- public void setLkm_gender(Character lkm_gender) {
- this.lkm_gender = lkm_gender;
- }
- public String getLkm_name() {
- return lkm_name;
- }
- public void setLkm_name(String lkm_name) {
- this.lkm_name = lkm_name;
- }
- public String getLkm_phone() {
- return lkm_phone;
- }
- public void setLkm_phone(String lkm_phone) {
- this.lkm_phone = lkm_phone;
- }
- public String getLkm_email() {
- return lkm_email;
- }
- public void setLkm_email(String lkm_email) {
- this.lkm_email = lkm_email;
- }
- public String getLkm_qq() {
- return lkm_qq;
- }
- public void setLkm_qq(String lkm_qq) {
- this.lkm_qq = lkm_qq;
- }
- public String getLkm_mobile() {
- return lkm_mobile;
- }
- public void setLkm_mobile(String lkm_mobile) {
- this.lkm_mobile = lkm_mobile;
- }
- public String getLkm_memo() {
- return lkm_memo;
- }
- public void setLkm_memo(String lkm_memo) {
- this.lkm_memo = lkm_memo;
- }
- public String getLkm_position() {
- return lkm_position;
- }
- public void setLkm_position(String lkm_position) {
- this.lkm_position = lkm_position;
- }
- }
- View Code Customer.hbm.xml:
- <?xml version="1.0" encoding="UTF-8" ?>
- <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD
- 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
- <hibernate-mapping package="domain">
- <class name="Customer" table="cst_customer">
- <id name="cust_id">
- <generator class="native">
- </generator>
- </id>
- <property name="cust_name" column="cust_name">
- </property>
- <property name="cust_source" column="cust_source">
- </property>
- <property name="cust_industry" column="cust_industry">
- </property>
- <property name="cust_level" column="cust_level">
- </property>
- <property name="cust_linkman" column="cust_linkman">
- </property>
- <property name="cust_phone" column="cust_phone">
- </property>
- <property name="cust_mobile" column="cust_mobile">
- </property>
- <!-- 集合, 一对多关系, 在配置文件中配置 -->
- <!-- name 属性: 集合属性名 column 属性: 外键列名 class 属性: 与我关联的对象完整类名 -->
- <set name="linkMens">
- <key column="lkm_cust_id">
- </key>
- <one-to-many class="LinkMan" />
- </set>
- </class>
- </hibernate-mapping>
- View Code LinkMan.hbm.xml:
- <?xml version="1.0" encoding="UTF-8"?>
- <!DOCTYPE hibernate-mapping PUBLIC
- "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
- "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
- <hibernate-mapping package="domain" >
- <class name="LinkMan" table="cst_linkman" >
- <id name="lkm_id" >
- <generator class="native"></generator>
- </id>
- <property name="lkm_gender" ></property>
- <property name="lkm_name" ></property>
- <property name="lkm_phone" ></property>
- <property name="lkm_email" ></property>
- <property name="lkm_qq" ></property>
- <property name="lkm_mobile" ></property>
- <property name="lkm_memo" ></property>
- <property name="lkm_position" ></property>
- <!-- 多对一 -->
- <!--
- name 属性: 引用属性名
- column 属性: 外键列名
- class 属性: 与我关联的对象完整类名
- -->
- <many-to-one name="customer" column="lkm_cust_id" class="Customer" ></many-to-one>
- </class>
- </hibernate-mapping>
- View Code
核心配置文件:
hibernate.cfg.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>
- <!-- 数据库驱动 -->
- <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
- <!-- 数据库 url -->
- <property name="hibernate.connection.url">jdbc:mysql:///hibernate</property>
- <!-- 数据库连接用户名 -->
- <property name="hibernate.connection.username">root</property>
- <!-- 数据库连接密码 -->
- <property name="hibernate.connection.password">xuyiqing</property>
- <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
- <!-- 将 hibernate 生成的 sql 语句打印到控制台 -->
- <property name="hibernate.show_sql">true</property>
- <!-- 将 hibernate 生成的 sql 语句格式化 (语法缩进) -->
- <property name="hibernate.format_sql">true</property>
- <property name="hibernate.hbm2ddl.auto">update</property>
- <!-- 引入 orm 元数据 路径书写: 填写 src 下的路径 -->
- <property name="hibernate.connection.isolation">4</property>
- <!-- 指定 session 与当前线程绑定 -->
- <property name="hibernate.current_session_context_class">thread</property>
- <mapping resource="domain/Customer.hbm.xml" />
- <mapping resource="domain/LinkMan.hbm.xml" />
- </session-factory>
- </hibernate-configuration>
- View Code
自定义工具类:
- package utils;
- import org.hibernate.Session;
- import org.hibernate.SessionFactory;
- import org.hibernate.cfg.Configuration;
- public class HibernateUtils {
- private static SessionFactory sf;
- static {
- //1 创建, 调用空参构造
- Configuration conf = new Configuration().configure();
- //2 根据配置信息, 创建 SessionFactory 对象
- sf = conf.buildSessionFactory();
- }
- // 获得 session => 获得全新 session
- public static Session openSession() {
- //3 获得 session
- Session session = sf.openSession();
- return session;
- }
- // 获得 session => 获得与线程绑定的 session
- public static Session getCurrentSession() {
- //3 获得 session
- Session session = sf.getCurrentSession();
- return session;
- }
- }
- View Code
测试类:
- package oneTomany;
- import org.hibernate.Session;
- import org.hibernate.Transaction;
- import org.junit.Test;
- import domain.Customer;
- import domain.LinkMan;
- import utils.HibernateUtils;
- // 一对多 | 多对一关系操作
- public class Demo {@Test
- // 保存客户 以及客户 下的联系人
- public void fun1() {
- //1 获得 session
- Session session = HibernateUtils.openSession();
- //2 开启事务
- Transaction tx = session.beginTransaction();
- //-------------------------------------------------
- //3 操作
- Customer c = new Customer();
- c.setCust_name("腾讯");
- LinkMan lm1 = new LinkMan();
- lm1.setLkm_name("马化腾");
- LinkMan lm2 = new LinkMan();
- lm2.setLkm_name("张三");
- // 表达一对多, 客户下有多个联系人
- c.getLinkMens().add(lm1);
- c.getLinkMens().add(lm2);
- // 表达多对一, 联系人属于哪个客户
- lm1.setCustomer(c);
- lm2.setCustomer(c);
- session.save(c);
- session.save(lm1);
- session.save(lm2);
- //-------------------------------------------------
- //4 提交事务
- tx.commit();
- //5 关闭资源
- session.close();
- }@Test
- // 为客户增加联系人
- public void fun2() {
- //1 获得 session
- Session session = HibernateUtils.openSession();
- //2 开启事务
- Transaction tx = session.beginTransaction();
- //-------------------------------------------------
- //3 操作
- //1> 获得要操作的客户对象
- Customer c = session.get(Customer.class, 1l);
- //2> 创建联系人
- LinkMan lm1 = new LinkMan();
- lm1.setLkm_name("李四");
- //3> 将联系人添加到客户, 将客户设置到联系人中
- c.getLinkMens().add(lm1);
- lm1.setCustomer(c);
- //4> 执行保存
- session.save(lm1);
- //-------------------------------------------------
- //4 提交事务
- tx.commit();
- //5 关闭资源
- session.close();
- }@Test
- // 为客户删除联系人
- public void fun3() {
- //1 获得 session
- Session session = HibernateUtils.openSession();
- //2 开启事务
- Transaction tx = session.beginTransaction();
- //-------------------------------------------------
- //3 操作
- //1> 获得要操作的客户对象
- Customer c = session.get(Customer.class, 1l);
- //2> 获得要移除的联系人
- LinkMan lm = session.get(LinkMan.class, 3l);
- //3> 将联系人从客户集合中移除
- c.getLinkMens().remove(lm);
- lm.setCustomer(null);
- //-------------------------------------------------
- //4 提交事务
- tx.commit();
- //5 关闭资源
- session.close();
- }
- }
进阶操作一: cascade
上边 fun1 代码这一段:
- session.save(c);
- session.save(lm1);
- session.save(lm2);
这里发现: 如果有很多个联系人, 依次保存联系人代码量大, 有没有一种方法, 在保存客户的同时保存所有的联系人呢?
级联操作: cascade
save-update: 级联保存更新
delete: 级联删除
all:save-update+delete
级联操作: 简化操作. 目的就是为了少些两行代码.
配置文件:
- <set name="linkMens" cascade="save-update" >
- <key column="lkm_cust_id" ></key>
- <one-to-many class="LinkMan" />
- </set>
这里就做到了级联保存
同样还有级联删除: 删除客户, 那么所有该客户所有联系人都将被删除
注意: 客户和联系人配置文件都可以设置 cascade 属性
进阶操作二:
关系维护属性: inverse
多表操作的时候, 会自动维护双方, 影响效率, 这里可以取消其中的维护以提高效率
在这里, 客户一方可以不维护 (即设置该属性为 true)
- <set name="linkMens" inverse="true" cascade="delete" >
- <key column="lkm_cust_id" ></key>
- <one-to-many class="LinkMan" />
- </set>
inverse 属性: 配置关系是否维护.
true: customer 不维护关系
false(默认值): customer 维护关系
inverse 属性: 性能优化. 提高关系维护的性能.
原则: 无论怎么放弃, 总有一方必须要维护关系.
注意:
一对多关系中: 一的一方放弃. 也只能一的一方放弃. 多的一方不能放弃.
来源: http://www.bubuko.com/infodetail-2500390.html