Hibernate 使用注释

Posted 2021-01-11 xxcxxc

Hibernate 使用注释

Hibernate使用注释有个好处就是我们不需要建立.hbm.xml文件，直接在实体类中添加注解就可以完成往数据库中进行数据操作

配置文件：hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>

    <session-factory>
        <!-- Database connection settings -->
      <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
      <property name="connection.url">jdbc:mysql://localhost:3306/student?serverTimezone=UTC</property>
      <property name="connection.username">root</property>
      <property name="connection.password">123456</property>

      <!-- JDBC connection pool (use the built-in) -->
      <!-- <property name="connection.pool_size">1</property> -->

      <!-- SQL dialect 方言 MySQLDialect不同数据库不一样-->
      <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

      <!-- Enable Hibernate‘s automatic session context management -->
      <!-- <property name="current_session_context_class">thread</property> -->

      <!-- Disable the second-level cache -->
      <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

      <!-- Echo all executed SQL to stdout  生产的sql打印出来-->
      <property name="show_sql">true</property>
      <!-- <mapping resource="com/xxc/model/Student.hbm.xml"></mapping> -->
      <mapping class="com.xxc.model.Teacher"></mapping>
    </session-factory>

</hibernate-configuration>

实体类Teacher.java

package com.xxc.model;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="teacher")
public class Teacher {
    private int id;
    private String name;
    private String title;
    @Id
    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 String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    
}

 

操作类TeacherTest.java

 在这里，我们使用StandardServiceRegistryBuilder类和MetadataSources类从持久化类获取映射的信息。

package hibernateTest;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

import com.xxc.model.Teacher;

public class TeacherTest {

    public static void main(String[] args) {
        Teacher t = new Teacher();
        t.setId(1);
        t.setName("xxc");
        t.setTitle("高级");
        final StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build();
        SessionFactory sf = new MetadataSources(registry).buildMetadata().buildSessionFactory();
        Session session = sf.openSession();
        //开始事务    
        session.beginTransaction();
        session.save(t);
        //结束事务
        session.getTransaction().commit();
        session.close();
        sf.close();
    }
}