Hibernate静态单例模式查询-优快云博客

本文链接：https://blog.youkuaiyun.com/ChanceYing/article/details/117912651

这篇博客展示了如何配置Hibernate实体类，包括User_old类的属性和getter/setter方法，以及对应的XML映射文件。文章还给出了Hibernate配置文件的更新部分，用于引入实体类的映射资源。最后，通过一个测试函数演示了如何利用Hibernate进行数据库查询并打印结果。

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文章目录

实体类
hibernate配置文件
测试函数

实体类

实体类及其对应的xml文件

package entity;

public class User_old {
    private int id;
    private String name;
    private int age;
    private int gender;
    private IdCard group;

    public IdCard getGroup() {
        return group;
    }

    public void setGroup(IdCard idCard) {
        this.group = idCard;
    }

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public void setGender(int gender) {
        this.gender = gender;
    }

    public int getGender() {
        return gender;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", gender=" + gender +
                '}';
    }
    public User_old(String name, int age, int gender){
        this.name = name;
        this.age = age;
        this.gender = gender;
    }
    public User_old(String name, int age){
        this.name = name;
        this.age = age;
    }
    public User_old(){

    }
}

    /*
    public User(String name){
        this.name = name;
        this.age = 0;
    }
    public User(String name, int age){
        this.name = name;
        this.age = age;
    }
    public User(){
    }*/

<?xml version="1.0"?>
<!--
  ~ Hibernate, Relational Persistence for Idiomatic Java
  ~
  ~ License: GNU Lesser General Public License (LGPL), version 2.1 or later.
  ~ See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
  -->
<!DOCTYPE hibernate-mapping PUBLIC
	"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
	"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="entity.User_old" table="t_user">
        <id name="id" column="id">
            <generator class="native"/>
        </id>
        <property name="name" column="name" />
        <property name="age" column="age"/>
        <property name="gender" column="gender"/>
    </class>
</hibernate-mapping>

数据库添加少量数据
在这里插入图片描述

hibernate配置文件

在原有配置文件中加入

<mapping resource="entity/user_old.hbm.xml"/>

测试函数

    @Test
    public void HibernateUtil(){
        Configuration cfg = null;
        SessionFactory sf = null;
        Session session = null;
        Transaction ts = null;
        try {
            cfg = new Configuration().configure();
            sf = cfg.buildSessionFactory();
            session = sf.openSession();
            ts = session.beginTransaction();
            Query<User_old> Query = session.createQuery("from User_old ");
            List<User_old> us =Query.list();
            for (User_old u:us){
                System.out.println(u.toString());
            }
            ts.commit();
        }catch (HibernateException e){
            e.printStackTrace();
            if(ts != null){
                ts.rollback();
            }
        }finally {
            session.close();  // 持久->游离
            sf.close();
        }
    }