Hibernate映射集合属性1__Set集合

Set
  HashSet 无序,不重复
  
List
  有序,可重复

Map
  HashMap 无序,不重复(以key为准)

数组

e_user          e_user_addressSet
id              userId
name            address
要说明的信息:
  a:集合表的名称(集合表)
  b:集合表中的外键(集合外键)
  c:集合表中的元素列(集合元素)

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 导入包 -->
<hibernate-mapping package="cn.itcast.e_hbm_collection">
  <!-- 类名 -->
  <class name="User" table="e_user">
    <id name="id" type="integer" column="id_">
      <generator class="native" />
    </id>
    <property name="name" type="string" column="name_" />
    <!-- addressSet属性,Set集合 -->
    <set name="addressSet" table="e_user_addressSet">
      <key column="userId"></key>
      <element type="string" column="address_"></element>
    </set>
  </class>
</hibernate-mapping>

package cn.itcast.e_hbm_collection;

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

public class User {
  private Integer id;
  private String name;
  private Set<String> addressSet = new HashSet<String>();// Set集合

  public Integer getId() {
    return id;
  }

  public void setId(Integer id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Set<String> getAddressSet() {
    return addressSet;
  }

  public void setAddressSet(Set<String> addressSet) {
    this.addressSet = addressSet;
  }

}

package cn.itcast.e_hbm_collection;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.Test;

public class App {
  private static SessionFactory sessionFactory = new Configuration()//
      .configure()//
      .addClass(User.class)//
      .buildSessionFactory();

  @Test
  public void testSave() throws Exception {
    Session session = sessionFactory.openSession();
    Transaction tx = null;
    try {
      tx = session.beginTransaction();
      // ------------------------------------
      // 操作
      // Set<String> set = new HashSet<String>();
      // set.add("骆家庄东苑");
      // set.add("文一新西路");

      // 构建对象
      User user = new User();
      user.setName("李四");
      user.getAddressSet().add("新青年厂场");
      user.getAddressSet().add("新塘路");

      // 保存
      session.save(user);
      // ------------------------------------
      tx.commit();
    } catch (RuntimeException e) {
      tx.rollback();
      throw e;
    } finally {
      session.close();
    }
  }

  @Test
  public void testGet() throws Exception {
    Session session = sessionFactory.openSession();
    Transaction tx = null;
    try {
      tx = session.beginTransaction();
      // ------------------------------------

      // 获取数据
      User user = (User) session.get(User.class, 2);

      // 显示信息
      System.out.println(user.getId());
      System.out.println(user.getName());
      for (String s : user.getAddressSet()) {
        System.out.println(s);
      }

      // ------------------------------------
      tx.commit();
    } catch (RuntimeException e) {
      tx.rollback();
      throw e;
    } finally {
      session.close();
    }
  }
}