Hibernate内存储器排序

2012-08-09

Hibernate内存排序内存排序内存排序和数据库排序唯一的不同就是在配置文件中使用sort属性而不是order-by属

Hibernate内存排序

内存排序
内存排序和数据库排序唯一的不同就是在配置文件中使用sort属性而不是order-by属性
他有三个属性值(unsorted,natural),其中natural指的是按照自然的升序排序，第三个
属性值是我们自己定义的排序规则类，该规则类通过实现Comparator接口，并且实现
该接口中的Compare方法,在该方法中定义排序规则即可。然后将该自定义的排序规则
的类名作为sort的属性值即可.

具体参考:

Team.java

package com.fgh.hibernate;import java.util.Set;public class Team {private String id;private String teamName;private Set<Student> students;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getTeamName() {return teamName;}public void setTeamName(String teamName) {this.teamName = teamName;}public Set<Student> getStudents() {return students;}public void setStudents(Set<Student> students) {this.students = students;}}
Student.java

package com.fgh.hibernate;/** * 一对一双向关联 * * @author fgh * */public class Student {private String id;private String name;private String idCard;private int age;private Team team;public Team getTeam() {return team;}public void setTeam(Team team) {this.team = team;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getIdCard() {return idCard;}public void setIdCard(String idCard) {this.idCard = idCard;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}
Team.hbm.xml

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping><class name="com.fgh.hibernate.Student" table="student"><id name="id" column="id" type="string"><generator column="name" type="string"></property><property name="idCard" column="idcard" type="string"></property><property name="age" column="age" type="integer"></property><many-to-one name="team" name="code">package com.fgh.hibernate;import java.util.Comparator;/** * 自定义排序规则类 * * @author fgh * */public class MyComparator implements Comparator<Student> {public int compare(Student s1, Student s2) {//如果两个对象相同，不排序if (s1 == s2) {return 0;}int result = s1.getIdCard().compareToIgnoreCase(s2.getIdCard());//如果cardId不同，按照cardId排序if (result != 0) {//如果降序 return -result;return result;}//如果cardId相同，按照name排序//如果降序返回负值return s1.getName().compareToIgnoreCase(s2.getName());}}
测试类：

HIbernateTest.java

package com.fgh.hibernate;import java.util.HashSet;import java.util.Iterator;import java.util.Set;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;public class HibernateTest {private static SessionFactory sessionFactory;static {try {sessionFactory = new Configuration().configure().buildSessionFactory();} catch (Exception e) {e.printStackTrace();}}public static void main(String[] args) {// 先执行插入操作有了数据才可以查询哦// ------------begin--------------Team team = new Team();team.setTeamName("team1");team.setStudents(new HashSet<Student>());Student student = new Student();student.setName("zhangsan");student.setIdCard("aa");student.setAge(20);Student student1 = new Student();student1.setName("lisi");student1.setIdCard("aa");student1.setAge(21);Student student2 = new Student();student2.setName("wangwu");student2.setIdCard("ba");student2.setAge(22);Student student3 = new Student();student3.setName("xiaoqiang");student3.setIdCard("bb");student3.setAge(23);Student student4 = new Student();student4.setName("xiaohong");student4.setIdCard("dc");student4.setAge(24);team.getStudents().add(student);team.getStudents().add(student1);team.getStudents().add(student2);team.getStudents().add(student3);team.getStudents().add(student4);student.setTeam(team);student1.setTeam(team);student2.setTeam(team);student3.setTeam(team);student4.setTeam(team);// -------------end------------Session session = sessionFactory.openSession();Transaction tx = null;try {tx = session.beginTransaction();// 查询----bein--------Team team2 = (Team) session.get(Team.class,"8a8ae4d934b2bfa10134b2bfa4a30001");Set<Student> set = team2.getStudents();for (Iterator<Student> iterator = set.iterator(); iterator.hasNext();) {System.out.println(iterator.next().getName());}// --------------end----------// 保存// session.save(team);tx.commit();} catch (Exception e) {e.printStackTrace();if (null != tx) {tx.rollback();}} finally {session.close();}}}打印sql：

Hibernate: select team0_.id as id1_0_, team0_.teamName as teamName1_0_ from team team0_ where team0_.id=?Hibernate: select students0_.team_id as team5_1_, students0_.id as id1_, students0_.id as id0_0_, students0_.name as name0_0_, students0_.idcard as idcard0_0_, students0_.age as age0_0_, students0_.team_id as team5_0_0_ from student students0_ where students0_.team_id=?lisizhangsanwangwuxiaoqiangxiaohong
哦也，完成

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Hibernate内存储器排序