Hibernate内存储器排序

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

Hibernate内存储器排序

热点推荐