Hibernate的执行流程和集合的映射关系
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Hibernate的执行流程
集合映射
准被hibernate的运行环境
配置hibernate.cfg.xml主配置文件
1、Set集合
写User.java类
package com.gqx.collection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* javaBean的设计
* @author 郭庆兴
*
*/
public class User {
private int userId;
private String userName;
//一个用户对应多个地址
private Set<String> address;
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 Set<String> getAddress() {
return address;
}
public void setAddress(Set<String> address) {
this.address = address;
}
}
映射文件User.hbm.xml
<?xml version="1.0"?> <!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.gqx.collection"> <class name="User" table="t_users"> <!-- 主键字段 --> <id name="userId" column="id"> <generator class="native"/> </id> <property name="userName" ></property> <!-- set集合属性的映射,指定要映射的set集合的属性 table 集合属性要映射到的表 key 指定属性集合表（t_address)的外键字段 element 指定集合表的其他字段--> <set name="address" table="t_address"> <key column="uid"></key> <element column="address" type="string"></element> </set> </class> </hibernate-mapping>
测试类如下：
public class App {
private static SessionFactory sf;
static{
sf=new Configuration().configure().addClass(User.class).buildSessionFactory();
}
/**
* Set集合
*/
@Test
public void test() {
Session session=sf.openSession();
session.beginTransaction();
//**************保存************
Set<String> addressSet=new HashSet<String>();
addressSet.add("黄石");
addressSet.add("荆州");
User user=new User();
user.setAddress(addressSet);
user.setUserName("gqxing");
session.save(user);
session.getTransaction().commit();
session.close();
}
}
2、List集合User.java
package com.gqx.collection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* javaBean的设计
* @author 郭庆兴
*
*/
public class User {
private int userId;
private String userName;
//一个用户对应多个地址
private List<String> addressList=new ArrayList<String>();
public void setAddressList(List<String> addressList) {
this.addressList = addressList;
}
public List<String> getAddressList() {
return addressList;
}
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;
}
}
映射文件（User.hbm.xml）
<?xml version="1.0"?> <!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.gqx.collection"> <class name="User" table="t_users"> <!-- 主键字段 --> <id name="userId" column="id"> <generator class="native"/> </id> <property name="userName" ></property> <!-- List集合 list-index：指定的是集合排列的顺序（因为要保证List集合的有序） --> <list name="addressList" table="t_addressList"> <key column="uid"></key> <list-index column="idx"></list-index> <element column="address" type="string"></element> </list> </class> </hibernate-mapping>
测试类：
/**
* List集合
*/
@Test
public void testSaveList() {
Session session=sf.openSession();
session.beginTransaction();
//**************保存************
User user=new User();
user.setUserName("gqxing");
user.getAddressList().add("武汉");
user.getAddressList().add("上海");
session.save(user);
session.getTransaction().commit();
session.close();
}
3、Map集合
User.java
package com.gqx.collection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* javaBean的设计
* @author 郭庆兴
*
*/
public class User {
private int userId;
private String userName;
//一个用户对应多个地址
private Map<String, String> addressMap=new HashMap<String, String>();
public void setAddressMap(Map<String, String> addressMap) {
this.addressMap = addressMap;
}
public Map<String, String> getAddressMap() {
return addressMap;
}
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;
}
}
映射文件
<?xml version="1.0"?> <!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.gqx.collection"> <class name="User" table="t_users"> <!-- 主键字段 --> <id name="userId" column="id"> <generator class="native"/> </id> <property name="userName" ></property> <!-- map集合映射 key:指定外键字段 map-key：指定map的key element：指定map的value --> <map name="addressMap" table="t_addressMap"> <key column="uid"></key> <map-key type="string" column="shortName"></map-key> <element column="address" type="string"></element> </map> </class> </hibernate-mapping>
测试类
/**
* List集合
*/
@Test
public void testSaveMap() {
Session session=sf.openSession();
session.beginTransaction();
//**************保存************
User user=new User();
user.setUserName("gqxing");
user.getAddressMap().put("A002", "黄石");
user.getAddressMap().put("A001", "荆州");
session.save(user);
session.getTransaction().commit();
session.close();
}
集合的获取
测试类
/**
* 获取
*/
@Test
public void testGet() {
Session session=sf.openSession();
session.beginTransaction();
//获取
User user=(User)session.get(User.class, 2); //及时加载
System.out.println(user.getUserId());
System.out.println(user.getUserName());
//当查询用户，可以获取与亲关联的list集合的数据（因为有正确的映射）
//当遇到到集合数据的使用时，才向数据库发送执行的sql语句(懒加载）
System.out.println(user.getAddressList());
session.getTransaction().commit();
session.close();
}
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