Hibernate学习-6-集合映射保存和集合数据获取案例

package com.cxspace.collection;

import java.util.*;

/**
* Created by cxspace on 16-7-24.
*/
public class User {

private int userId;

private String userName;

//存储的对象无序
private Set<String> address;

private List<String> addressList = new ArrayList<String>();

private Map<String , String> addressMap = new HashMap<String, String>();

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;
}

public List<String> getAddressList() {
return addressList;
}

public void setAddressList(List<String> addressList) {
this.addressList = addressList;
}

public Map<String, String> getAddressMap() {
return addressMap;
}

public void setAddressMap(Map<String, String> addressMap) {
this.addressMap = addressMap;
}
}

<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<!-- 通常，一个session-factory节点代表一个数据库 -->
<session-factory>

<!-- 1. 数据库连接配置 -->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql:///learnstruts</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">33269456.cx</property>
<!--
数据库方法配置， hibernate在运行的时候，会根据不同的方言生成符合当前数据库语法的sql
-->
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>

<!-- 2. 其他相关配置 -->
<!-- 2.1 显示hibernate在运行时候执行的sql语句 -->
<property name="hibernate.show_sql">true</property>
<!-- 2.2 格式化sql
<property name="hibernate.format_sql">true</property>  -->
<!-- 2.3 自动建表  -->
<property name="hibernate.hbm2ddl.auto">update</property>

<!-- 3. 加载所有映射
<mapping resource="cn/itcast/a_hello/Employee.hbm.xml"/>
-->

</session-factory>
</hibernate-configuration>

<?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.cxspace.collection">

<class name="User" table="t_user">
<id name="userId" column="id">
<generator class="native"></generator>
</id>
<property name="userName"></property>

<!--
set集合属性映射
name 指定要映射的set集合的属性
table 集合属性要映射到的表
key 指定集合表的外键字段
element 指定集合表的其他字段

type 元素类型，一定要指定
-->

<set name="address" table="t_address">
<key column="uid"></key>
<element column="address" type="java.lang.String"></element>
</set>

<!--
list集合映射
list-index 指定的时排序列的名称（要保证list集合有序）
-->

<list name="addressList" table="t_addressList">
<key column="uid"></key>
<list-index column="idx"></list-index>
<element column="address" type="java.lang.String"></element>
</list>

<!--
map集合映射
key 指定的外键字段uid
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 column="shortName" type="java.lang.String"></map-key>
<element column="address" type="java.lang.String"></element>
</map>

</class>

</hibernate-mapping>

package com.cxspace.collection;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

import java.util.HashSet;
import java.util.Set;

/**
* Created by cxspace on 16-7-24.
*/
public class Test {

private static SessionFactory sf;

static {

sf  = new Configuration()
.configure()
.addClass(User.class)
.buildSessionFactory();
}

public void testSaveSet() throws Exception{

Session session = sf.openSession();
session.beginTransaction();

Set<String> addressSet = new HashSet<String>();
addressSet.add("北京");
addressSet.add("深圳");

User user = new User();

user.setUserName("cx");
user.setAddress(addressSet);

session.save(user);

session.getTransaction().commit();
session.close();

}

public void testSaveList() throws Exception{

Session session = sf.openSession();
session.beginTransaction();

User user = new User();

user.setUserName("sike");

user.getAddressList().add("上海");
user.getAddressList().add("杭州");

session.save(user);

session.getTransaction().commit();
session.close();

}

@org.junit.Test
public void testSaveMap() throws Exception{

Session session = sf.openSession();
session.beginTransaction();

User user = new User();
user.setUserName("kill");

user.getAddressMap().put("a0001","广州");
user.getAddressMap().put("a0002","南昌");

session.save(user);

session.save(user);

session.getTransaction().commit();
session.close();
}
}

public void testGet() throws Exception{

Session session = sf.openSession();

session.beginTransaction();

User user = (User) session.get(User.class , 3);  //及时加载

System.out.println(user.getUserId());

System.out.println(user.getUserName());

/*
当查询用户，同时可以获取用户关联的list集合的数据（因为有正确的映射）

当使用到集合数据的使用，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();

}