Hibernate是一个开放源代码的对象关系映射框架，可以应用在任何使用JDBC的场合，既可以在Java的客户端程序实用，也可以在Servlet/JSP的Web应用中使用
优势：
简化开发，提高开发效率，持久层关系映射复杂情况下，hibernate开发效率相当高。
hibernate内部进行了JDBC的优化处理，以及增加缓存机制，大大提高了运行效率。
更好的移植性，Hibernate已经为我们屏蔽了数据库之间的差异
Hibernate使用 Java 反射机制 而不是字节码增强程序来实现透明性。
Hibernate的性能非常好，因为它是个轻量级框架。 映射的灵活性很出色。
Hibernate它支持各种关系数据库，从一对一到多对多的各种复杂关系。
代码结构
实体类User
public class User { ???????private int id; ???private String name; ???private Date birthday; ???private int age; ???private int total; ???????????public User() { ???????// TODO Auto-generated constructor stub ???} ???public User(String name, Date birthday, int age) { ???????super(); ???????this.name = name; ???????this.birthday = birthday; ???????this.age = age; ???} ???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 Date getBirthday() { ???????return birthday; ???} ???public void setBirthday(Date birthday) { ???????this.birthday = birthday; ???} ???public int getTotal() { ???????return total; ???} ???public void setTotal(int total) { ???????this.total = total; ???} ???public int getAge() { ???????return age; ???} ???public void setAge(int age) { ???????this.age = age; ???} ???}orm映射文件User.hbm.xml
<?xml version="1.0" encoding="UTF-8"?><!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="com.domain.User" table="user" catalog="ssh"> ??????<id name="id" column="id" type="int"> ??????????<generator class="native"></generator> ??????</id> ??????<property name="name" column="name" type="java.lang.String"></property> ??????<property name="age"> ?????????<column name="age" sql-type="int"></column> ??????</property> ??????<property name="birthday" type="date"></property> ??????<property name="total" formula="(select count(*) from user)"></property> ???</class></hibernate-mapping>
核心配置文件hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-configuration PUBLIC ???"-//Hibernate/Hibernate Configuration DTD 3.0//EN" ???"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"><hibernate-configuration> ??<session-factory> ???????<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> ???????<property name="hibernate.connection.url">jdbc:mysql:///ssh</property> ???????<property name="hibernate.connection.username">root</property> ???????<property name="hibernate.connection.password">root</property> ???????<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> ???????<property name="hibernate.show_sql">true</property> ???????<property name="hibernate.format_sql">true</property> ???????<property name="hibernate.hbm2ddl.auto">update</property> ???????<property name="javax.persistence.validation.mode">none</property>
???????//这里需要配置进来 ???????<mapping resource="com/domain/User.hbm.xml"/> ??</session-factory></hibernate-configuration>
HibernateUtils工具类
public class HibernateUtils { ???private static Configuration configuration; ???private static SessionFactory sessionFactory; ???static { ???????configuration = new Configuration().configure(); ???????sessionFactory = configuration.buildSessionFactory(); ???} ???public static Session openSession() { ???????return sessionFactory.openSession(); ???}}UserTest测试类
public class UserTest { ???????//派生属性 ???@Test ???public void total(){ ???????Session session=HibernateUtils.openSession(); ???????Transaction transaction = session.beginTransaction(); ???????User user = (User) session.get(User.class, 6); ???????System.out.println(user.getTotal()); ???????transaction.commit(); ???????session.close(); ???} ???//删除 ???@Test ???public void delete(){ ???????Session session=HibernateUtils.openSession(); ???????Transaction transaction = session.beginTransaction(); ???????User user=new User(); ???????user.setId(3); ???????session.delete(user); ???????transaction.commit(); ???????session.close(); ???}//通过ID查询 ???@Test ???public void findById(){ ???????Session session=HibernateUtils.openSession(); ???????Transaction transaction = session.beginTransaction(); ???????User user=(User) session.get(User.class, 3); ???????System.out.println(user); ???????transaction.commit(); ???????session.close(); ???}//添加 ???@Test ???public void add(){ ???????Session session = HibernateUtils.openSession(); ???????Transaction transaction = session.beginTransaction(); ???????for(int i=0;i<5;i++){ ???????????User user=new User("cai"+i,new Date(),12+i); ???????????session.save(user); ???????} ???????transaction.commit(); ???????session.close(); ???}}Hibernate快速入门
原文地址：https://www.cnblogs.com/weishao-lsv/p/8157599.html