今天配置Hibernate配置了好久，各种改错。说实话，我并没有感觉到使用Hibernate的方便之处，至少比Django麻烦的多。
下面总结一下今天对Hibernate的使用。
1、下载Hibernate
到这里http://hibernate.org/orm/releases/下载，我使用的是java 8，所有下载了5.2。下载后解压，将required文件下的jar文件加入的工程中去。
2、配置文件之hibernate.cfg.xml
<?xml version="1.0" encoding="utf-8"?><!DOCTYPE hibernate-configuration SYSTEM "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"><hibernate-configuration><session-factory> ???<property name="hibernate.dialect"> ???????org.hibernate.dialect.MySQLDialect ???</property> ???<property name="hibernate.connection.driver_class"> ???????com.mysql.jdbc.Driver ???</property> ???<!-- Assume test is the database name --> ???<property name="hibernate.connection.url"> ???????jdbc:mysql://localhost/pgv2 ???</property> ???<property name="hibernate.connection.username">root</property> ???<property name="hibernate.connection.password">1234</property> ???<!-- show_sql: 操作数据库时,会 向控制台打印sql语句 --> ???<property name="show_sql">true</property> ???<!-- format_sql: 打印sql语句前,会将sql语句先格式化 --> ???<property name="format_sql">true</property> ???<!-- 是否自动创建数据库表 他主要有一下几个值： validate:当sessionFactory创建时，自动验证或者schema定义导入数据库。 ????????create:每次启动都drop掉原来的schema，创建新的。 create-drop:当sessionFactory明确关闭时，drop掉schema。 ????????update(常用):如果没有schema就创建，有就更新。 --> ???<property name="hbm2ddl.auto">update</property> ???<!-- List of XML mapping files --> ???<property name="dialect"></property> ???<mapping resource="User.hbm.xml" /> ???<mapping resource="onlineUser.hbm.xml" /></session-factory></hibernate-configuration>
这里我加了一些注释，有些一眼就可以明白的东西就没有注释了（还是没有随手注释的习惯）。一般常用的配置这样就可以了。
我想说的是这个文件的存放位置，所有的hibernate的配置文件的存放位置，默认都在src下，我查了一些怎么修改也没有找到。真是让强迫症的我难受的很。。
这样就配置好了hibernate的数据库连接。
3、实体类
实体类要写入数据库的属性必须有setter和getter，必须有构造方法。如果是mysql数据库，必须有一个id作为主键，一般变量名也直接设置为id
看我的User类：
package com.PGV2.javaBean;public class User { ???private int id; ???private String userName; ???private String userPwd; ???private String role; ???private int login; ???public User( String userName, String userPwd, String role, int login) { ???????this.userName = userName; ???????this.userPwd = userPwd; ???????this.role = role; ???????this.login = login; ???} ???public User() { ???????// TODO Auto-generated constructor stub ???} ???public int getId() { ???????return id; ???} ???public void setId(int id) { ???????this.id = id; ???} ???public String getUserName() { ???????return userName; ???} ???public void setUserName(String userName) { ???????this.userName = userName; ???} ???public String getUserPwd() { ???????return userPwd; ???} ???public void setUserPwd(String userPwd) { ???????this.userPwd = userPwd; ???} ???public String getRole() { ???????return role; ???} ???public void setRole(String role) { ???????this.role = role; ???} ???public int isLogin() { ???????return login; ???} ???public void setLogin(int login) { ???????this.login = login; ???} ???????}要注意的是，id是自增的，不用写在构造方法里。
4、实体类配置文件 User.hbm.xml
<?xml version="1.0" encoding="utf-8"?><!DOCTYPE hibernate-mapping PUBLIC ?"-//Hibernate/Hibernate Mapping DTD//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping> ??<class name="com.PGV2.javaBean.User" table="user"> ?????<meta attribute="class-description"> ????????This class contains the User detail. ??????</meta> ?????<id name="id" type="int" column="id"> ????????<generator class="native"/> ?????</id> ?????<property name="userName" column="username" type="string"/> ?????<property name="userPwd" column="userpwd" type="string"/> ?????<property name="role" column="role" type="string"/> ?????<property name="login" column="login" type="int"/> ??</class></hibernate-mapping>
5、DAO操作
我把DAO操作直接封装在一个类中，这样用的时候示例化这个类就行。没有接口类，时间有限。。
我的manageUser.java
package com.PGV2.DAO;import java.util.List;import javax.management.Query;import java.util.Date;import java.util.Iterator;import org.hibernate.Criteria;import org.hibernate.HibernateException;import org.hibernate.Session;import org.hibernate.Transaction;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;import org.hibernate.criterion.Restrictions;import com.PGV2.javaBean.User;import com.PGV2.test.Employee;public class manageUser { ???private static SessionFactory factory; ???public manageUser() { ???????// TODO Auto-generated constructor stub ???????try { ???????????factory = new Configuration().configure().buildSessionFactory(); ???????} catch (Throwable ex) { ???????????System.err.println("Failed to create sessionFactory object." + ex); ???????????throw new ExceptionInInitializerError(ex); ???????} ???} ???/* ????* 增加一个用户 ????*/ ???public Integer addUser(User tmpUser) { ???????Session session = factory.openSession(); ???????Transaction tx = null; ???????Integer userID = null; ???????try { ???????????tx = session.beginTransaction(); ???????????User newUser = tmpUser; ???????????userID = (Integer) session.save(newUser); ???????????tx.commit(); ???????} catch (HibernateException e) { ???????????if (tx != null) ???????????????tx.rollback(); ???????????e.printStackTrace(); ???????} finally { ???????????session.close(); ???????} ???????return userID; ???} ???/* ????* 列出所有的用户 ????*/ ???public List listUsers() { ???????Session session = factory.openSession(); ???????Transaction tx = null; ???????List users = null; ???????try { ???????????tx = session.beginTransaction(); ???????????users = session.createQuery("FROM User").list(); ???????????for (Iterator iterator = users.iterator(); iterator.hasNext();) { ???????????????User tmpUser = (User) iterator.next(); ???????????????System.out.println(tmpUser.getUserName()); ???????????} ???????????tx.commit(); ???????} catch (HibernateException e) { ???????????if (tx != null) ???????????????tx.rollback(); ???????????e.printStackTrace(); ???????} finally { ???????????session.close(); ???????} ???????return users; ???} ???/* ????* 更新密码 ????*/ ???public void updateUserPwd(Integer userID, String pwd) { ???????Session session = factory.openSession(); ???????Transaction tx = null; ???????try { ???????????tx = session.beginTransaction(); ???????????User tmpUsere = (User) session.get(User.class, userID); ???????????tmpUsere.setUserPwd(pwd); ???????????; ???????????session.update(tmpUsere); ???????????tx.commit(); ???????} catch (HibernateException e) { ???????????if (tx != null) ???????????????tx.rollback(); ???????????e.printStackTrace(); ???????} finally { ???????????session.close(); ???????} ???} ???/* ????* 更新用户在线状态 ????*/ ???public void updateUser(User tmpUser){ ???????Session session = factory.openSession(); ???????Transaction tx = null; ???????try { ???????????tx = session.beginTransaction(); ???????????//User tmpUsere = (User) session.get(User.class, tmpUser.getId()); ???????????session.update(tmpUser); ???????????tx.commit(); ???????} catch (HibernateException e) { ???????????if (tx != null) ???????????????tx.rollback(); ???????????e.printStackTrace(); ???????} finally { ???????????session.close(); ???????} ???} ???/* ????* 删除一个用户 ????*/ ???public void deleteEmployee(Integer userID) { ???????Session session = factory.openSession(); ???????Transaction tx = null; ???????try { ???????????tx = session.beginTransaction(); ???????????User tmpUser = (User) session.get(User.class, userID); ???????????session.delete(tmpUser); ???????????tx.commit(); ???????} catch (HibernateException e) { ???????????if (tx != null) ???????????????tx.rollback(); ???????????e.printStackTrace(); ???????} finally { ???????????session.close(); ???????} ???} ???public User getUserById(Integer userID) { ???????Session session = factory.openSession(); ???????Transaction tx = null; ???????User tmpUser = null; ???????try { ???????????tx = session.beginTransaction(); ???????????tmpUser = (User) session.get(User.class, userID); ???????????tx.commit(); ???????} catch (HibernateException e) { ???????????if (tx != null) ???????????????tx.rollback(); ???????????e.printStackTrace(); ???????} finally { ???????????session.close(); ???????} ???????return tmpUser; ???} ???public User getUserByValid(String userName, String userPwd) { ???????Session session = factory.openSession(); ???????Transaction tx = null; ???????User tmpUser = null; ???????try { ???????????tx = session.beginTransaction(); ???????????org.hibernate.query.Query query = ????????????????????session.createQuery("from User u where u.userName = :name ?and u.userPwd = :pwd") ???????????????????????.setParameter("name", userName).setParameter("pwd", userPwd); ???????????List res = query.list(); ???????????if(res!=null||res.size()!=0){ ???????????????Iterator it = res.iterator(); ???????????????tmpUser = (User) it.next(); ???????????} ???????????tx.commit(); ???????} catch (Exception e) { ???????????// TODO Auto-generated catch block ???????????e.printStackTrace(); ???????}finally { ???????????session.close(); ???????} ???????return tmpUser; ???}}这里要特别说明有两个对应：
实体类配置文件的变量名要和实体类的变量名一致。
比如说我的User.java 里有变量：userName,我的User.hbm.xml里
<property name="userName" column="username" type="string"/>，这个对应的 name就应该是userName，至于大小写是否敏感，还没有验证。最后一致。然后column的值跟
????
数据库的列名一致。我一般不建立表格，让其自己生成，不容易出错。
第二个对应是这里：
org.hibernate.query.Query query = ????????????????????session.createQuery("from User u where u.userName = :name ?and u.userPwd = :pwd") ???????????????????????.setParameter("name", userName).setParameter("pwd", userPwd);这是我的manageUser中的一句话，使用hql查询数据库是否存在用户名和密码为我传入的两个值的记录。
这里的hql 语句中，from User，这个User对应的User.java这个类，当然u.userName和u.userPwd对应的就是User类的两个类成员变量。
Hibernate使用
原文地址：https://www.cnblogs.com/superxuezhazha/p/9136491.html