Hibernate学习第三天(1)(一对多关系映射)
今日任务:
项目图如下:
项目图:
首先学习一对多:
CREATE TABLE `cst_customer` ( `cust_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '客户编号(主键)', `cust_name` varchar(32) NOT NULL COMMENT '客户名称(公司名称)', `cust_source` varchar(32) DEFAULT NULL COMMENT '客户信息来源', `cust_industry` varchar(32) DEFAULT NULL COMMENT '客户所属行业', `cust_level` varchar(32) DEFAULT NULL COMMENT '客户级别', `cust_phone` varchar(64) DEFAULT NULL COMMENT '固定电话', `cust_mobile` varchar(16) DEFAULT NULL COMMENT '移动电话', PRIMARY KEY (`cust_id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8; CREATE TABLE `cst_linkman` ( `lkm_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '联系人编号(主键)', `lkm_name` varchar(16) DEFAULT NULL COMMENT '联系人姓名', `lkm_cust_id` bigint(32) DEFAULT NULL COMMENT '客户id', `lkm_gender` char(1) DEFAULT NULL COMMENT '联系人性别', `lkm_phone` varchar(16) DEFAULT NULL COMMENT '联系人办公电话', `lkm_mobile` varchar(16) DEFAULT NULL COMMENT '联系人手机', `lkm_email` varchar(64) DEFAULT NULL COMMENT '联系人邮箱', `lkm_qq` varchar(16) DEFAULT NULL COMMENT '联系人qq', `lkm_position` varchar(16) DEFAULT NULL COMMENT '联系人职位', `lkm_memo` varchar(512) DEFAULT NULL COMMENT '联系人备注', PRIMARY KEY (`lkm_id`), KEY `FK_cst_linkman_lkm_cust_id` (`lkm_cust_id`), CONSTRAINT `FK_cst_linkman_lkm_cust_id` FOREIGN KEY (`lkm_cust_id`) REFERENCES `cst_customer` (`cust_id`) ON DELETE NO ACTION ON UPDATE NO ACTION ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
多的一方:
此处略过 与前同!
注意看前提:双方都设置了级联操作。
也可以用逗号分隔:
以上多的一方和一的一方都会维护外键 造成服务器浪费,所以在一的一方取消外键维护权。
cascade是级联操作 inverse是外键维护操作 (只有一的一方存在) 所以如果客户级联了联系人 插入客户后 联系人也会会插入 但是因为inverse=true 所以外键为空。
进行此操作前 要把数据库设置为create(初始化 ) 同时取消联系人xml中的cascade 和客户xml中的delete级联删除配置。
客户:
联系人:
代码:
domain:
package com.hibernate.domain; import java.util.HashSet; import java.util.Set; /** * 客户的实体 * @author jt * */ 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_phone; private String cust_mobile; // 通过ORM方式表示:一个客户对应多个联系人。 // 放置的多的一方的集合。Hibernate默认使用的是Set集合。 private Set<LinkMan> linkMans = new HashSet<LinkMan>(); 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_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; } public Set<LinkMan> getLinkMans() { return linkMans; } public void setLinkMans(Set<LinkMan> linkMans) { this.linkMans = linkMans; } }
package com.hibernate.domain; /** * 联系人的实体 * @author jt *CREATE TABLE `cst_linkman` ( `lkm_id` BIGINT(32) NOT NULL AUTO_INCREMENT COMMENT '联系人编号(主键)', `lkm_name` VARCHAR(16) DEFAULT NULL COMMENT '联系人姓名', `lkm_cust_id` BIGINT(32) DEFAULT NULL COMMENT '客户id', `lkm_gender` CHAR(1) DEFAULT NULL COMMENT '联系人性别', `lkm_phone` VARCHAR(16) DEFAULT NULL COMMENT '联系人办公电话', `lkm_mobile` VARCHAR(16) DEFAULT NULL COMMENT '联系人手机', `lkm_email` VARCHAR(64) DEFAULT NULL COMMENT '联系人邮箱', `lkm_qq` VARCHAR(16) DEFAULT NULL COMMENT '联系人qq', `lkm_position` VARCHAR(16) DEFAULT NULL COMMENT '联系人职位', `lkm_memo` VARCHAR(512) DEFAULT NULL COMMENT '联系人备注', PRIMARY KEY (`lkm_id`), KEY `FK_cst_linkman_lkm_cust_id` (`lkm_cust_id`), CONSTRAINT `FK_cst_linkman_lkm_cust_id` FOREIGN KEY (`lkm_cust_id`) REFERENCES `cst_customer` (`cust_id`) ON DELETE NO ACTION ON UPDATE NO ACTION ) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8; */ public class LinkMan { //外键不建属性 建整体实体 private Long lkm_id; private String lkm_name; private String lkm_gender; private String lkm_phone; private String lkm_mobile; private String lkm_email; private String lkm_qq; private String lkm_position; private String lkm_memo; // 通过ORM方式表示:一个联系人只能属于某一个客户。 // 放置的是一的一方的对象。 private Customer customer; public Long getLkm_id() { return lkm_id; } public void setLkm_id(Long lkm_id) { this.lkm_id = lkm_id; } public String getLkm_name() { return lkm_name; } public void setLkm_name(String lkm_name) { this.lkm_name = lkm_name; } public String getLkm_gender() { return lkm_gender; } public void setLkm_gender(String lkm_gender) { this.lkm_gender = lkm_gender; } public String getLkm_phone() { return lkm_phone; } public void setLkm_phone(String lkm_phone) { this.lkm_phone = lkm_phone; } public String getLkm_mobile() { return lkm_mobile; } public void setLkm_mobile(String lkm_mobile) { this.lkm_mobile = lkm_mobile; } 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_position() { return lkm_position; } public void setLkm_position(String lkm_position) { this.lkm_position = lkm_position; } public String getLkm_memo() { return lkm_memo; } public void setLkm_memo(String lkm_memo) { this.lkm_memo = lkm_memo; } public Customer getCustomer() { return customer; } public void setCustomer(Customer customer) { this.customer = customer; } }
xml配置:
<?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> <class name="com.hibernate.domain.Customer" table="cst_customer"> <!-- 建立OID与主键映射 --> <id name="cust_id" column="cust_id"> <generator class="native"/> </id> <!-- 建立普通属性与数据库表字段映射 --> <property name="cust_name" column="cust_name" /> <property name="cust_source" column="cust_source"/> <property name="cust_industry" column="cust_industry"/> <property name="cust_level" column="cust_level"/> <property name="cust_phone" column="cust_phone"/> <property name="cust_mobile" column="cust_mobile"/> <!-- 配置一对多的映射:放置的多的一方的集合 --> <!-- set标签 : * name :多的一方的对象集合的属性名称。 * cascade:级联 * inverse:放弃外键维护权。(一的一方放弃,解决多余sql) --> <set name="linkMans" cascade="save-update" inverse="true"> <!-- key标签 * column:多的一方的外键的名称。 --> <key column="lkm_cust_id"/> <!-- one-to-many标签 * class :多的一方的类的全路径 --> <one-to-many class="com.hibernate.domain.LinkMan"/> </set> </class> </hibernate-mapping>
<?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> <class name="com.hibernate.domain.LinkMan" table="cst_linkman"> <!-- 建立OID与主键映射 --> <id name="lkm_id" column="lkm_id"> <generator class="native"/> </id> <!-- 建立普通属性与表字段映射 --> <property name="lkm_name"/> <property name="lkm_gender"/> <property name="lkm_phone"/> <property name="lkm_mobile"/> <property name="lkm_email"/> <property name="lkm_qq"/> <property name="lkm_position"/> <property name="lkm_memo"/> <!-- 配置多对一的关系:放置的是一的一方的对象 --> <!-- many-to-one标签 * name :一的一方的对象的属性名称。 * class :一的一方的类的全路径。 * column :在多的一方的表的外键的名称。 --> <many-to-one name="customer" class="com.hibernate.domain.Customer" column="lkm_cust_id"/> </class> </hibernate-mapping>
核心配置:
<?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> <!-- 连接数据库的基本参数 --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql:///hibernate3</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <!-- 配置Hibernate的方言 --> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <!-- 可选配置================ --> <!-- 打印SQL --> <property name="hibernate.show_sql">true</property> <!-- 格式化SQL --> <property name="hibernate.format_sql">true</property> <!-- 自动创建表 --> <property name="hibernate.hbm2ddl.auto">create</property> <!-- 配置C3P0连接池 --> <property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property> <!--在连接池中可用的数据库连接的最少数目 --> <property name="c3p0.min_size">5</property> <!--在连接池中所有数据库连接的最大数目 --> <property name="c3p0.max_size">20</property> <!--设定数据库连接的过期时间,以秒为单位, 如果连接池中的某个数据库连接处于空闲状态的时间超过了timeout时间,就会从连接池中清除 --> <property name="c3p0.timeout">120</property> <!--每3000秒检查所有连接池中的空闲连接 以秒为单位--> <property name="c3p0.idle_test_period">3000</property> <!-- 设置事务隔离级别 --> <property name="hibernate.connection.isolation">4</property> <!-- 配置当前线程绑定的Session --> <property name="hibernate.current_session_context_class">thread</property> <!-- 引入映射 --> <mapping resource="com/hibernate/domain/Customer.hbm.xml"/> <mapping resource="com/hibernate/domain/LinkMan.hbm.xml"/> <!-- <mapping resource="com/itheima/hibernate/domain/User.hbm.xml"/> <mapping resource="com/itheima/hibernate/domain/Role.hbm.xml"/> --> </session-factory> </hibernate-configuration>
测试类:
package com.hibernate.demo1; import org.hibernate.Session; import org.hibernate.Transaction; import org.junit.Test; import com.hibernate.domain.Customer; import com.hibernate.domain.LinkMan; import com.hibernate.utils.HibernateUtils; /** * 一对多测试ilei * @author ZWT * */ public class TestDemo1 { @Test // 保存2个客户 和 3个联系人 并且建立好关系 public void demo1() { Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); // 创建两个客户 Customer customer1 = new Customer(); customer1.setCust_name("王东"); Customer customer2 = new Customer(); customer2.setCust_name("赵洪"); // 创建三个联系人 LinkMan linkMan1 = new LinkMan(); linkMan1.setLkm_name("凤姐"); LinkMan linkMan2 = new LinkMan(); linkMan2.setLkm_name("如花"); LinkMan linkMan3 = new LinkMan(); linkMan3.setLkm_name("旺财"); // 设置关系: linkMan1.setCustomer(customer1); linkMan2.setCustomer(customer1); linkMan3.setCustomer(customer2); customer1.getLinkMans().add(linkMan1); customer1.getLinkMans().add(linkMan2); customer2.getLinkMans().add(linkMan3); // 保存数据: session.save(linkMan1); session.save(linkMan2); session.save(linkMan3); session.save(customer1); session.save(customer2); tx.commit(); } @Test // 一对多关系只保存一边是否可以(配置级联可以) public void demo2(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); Customer customer = new Customer(); customer.setCust_name("赵洪"); LinkMan linkMan = new LinkMan(); linkMan.setLkm_name("如花"); customer.getLinkMans().add(linkMan); linkMan.setCustomer(customer); // 只保存一边是否可以:不可以,报一个瞬时对象异常:持久态对象关联了一个瞬时态对象。 // session.save(customer); session.save(linkMan); tx.commit(); } @Test /** * 级联保存或更新操作: * * 保存客户级联联系人,操作的主体是客户对象,需要在Customer.hbm.xml中进行配置 * * <set name="linkMans" cascade="save-update"> */ public void demo3(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); Customer customer = new Customer(); customer.setCust_name("赵洪"); LinkMan linkMan = new LinkMan(); linkMan.setLkm_name("如花"); customer.getLinkMans().add(linkMan); linkMan.setCustomer(customer); session.save(customer); tx.commit(); } @Test /** * 级联保存或更新操作: * * 保存联系人级联客户,操作的主体是联系人对象,需要在LinkMan.hbm.xml中进行配置 * * <many-to-one name="customer" cascade="save-update" class="com.itheima.hibernate.domain.Customer" column="lkm_cust_id"/> */ public void demo4(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); Customer customer = new Customer(); customer.setCust_name("李兵"); LinkMan linkMan = new LinkMan(); linkMan.setLkm_name("凤姐"); customer.getLinkMans().add(linkMan); linkMan.setCustomer(customer); session.save(linkMan); tx.commit(); } @Test /** * 测试对象的导航 * * 前提:一对多的双方都设置cascade="save-update" */ public void demo5(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); Customer customer = new Customer(); customer.setCust_name("李兵"); LinkMan linkMan1 = new LinkMan(); linkMan1.setLkm_name("凤姐"); LinkMan linkMan2 = new LinkMan(); linkMan2.setLkm_name("如花"); LinkMan linkMan3 = new LinkMan(); linkMan3.setLkm_name("芙蓉"); linkMan1.setCustomer(customer); customer.getLinkMans().add(linkMan2); customer.getLinkMans().add(linkMan3); // 双方都设置了cascade session.save(linkMan1); // 发送几条insert语句 4条 // session.save(customer); // 发送几条insert语句 3条 // session.save(linkMan2); // 发送几条insert语句 1条 tx.commit(); } @Test /** * 级联删除: * * 删除客户级联删除联系人,删除的主体是客户,需要在Customer.hbm.xml中配置 * * <set name="linkMans" cascade="delete"> */ public void demo6(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); // 没有设置级联删除,默认情况:修改了联系人的外键为NULL,再删除客户 /*Customer customer = session.get(Customer.class, 7l); session.delete(customer);*/ // 删除客户,同时删除联系人 Customer customer = session.get(Customer.class, 7l); session.delete(customer); tx.commit(); } @Test /** * 级联删除: * * 删除联系人级联删除客户,删除的主体是联系人,需要在LinkMan.hbm.xml中配置 * * <many-to-one name="customer" cascade="delete"> */ public void demo7(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); // 删除客户,同时删除联系人 LinkMan linkMan = session.get(LinkMan.class, 3l); session.delete(linkMan); tx.commit(); } @Test /** * 将2号联系人原来归1号客户,现在改为2号客户 */ public void demo8(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); // 查询2号联系人 LinkMan linkMan = session.get(LinkMan.class, 2l); // 查询2号客户 Customer customer = session.get(Customer.class, 2l); // 双向的关联 linkMan.setCustomer(customer); customer.getLinkMans().add(linkMan); tx.commit(); } @Test /** * 将区分casecade和inverse的区别 */ public void demo9(){ Session session = HibernateUtils.getCurrentSession(); Transaction tx = session.beginTransaction(); Customer customer = new Customer(); customer.setCust_name("李兵"); LinkMan linkMan = new LinkMan(); linkMan.setLkm_name("凤姐"); customer.getLinkMans().add(linkMan); //在Customer.hbm.xml中配置了cascade="save-update" 也配置了inverse=true session.save(customer); //客户会插入数据库 联系人也会入库 但是外键为空 tx.commit(); } }