hibernate基本概念及初始配置

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hibernate.cfg.xml

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<?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>
<property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql:///hibernate</property><!-- ///表示连接本机的数据库localhost://3306 -->
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">1234</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property><!-- 数据库方言 -->

<property name="hibernate.hbm2ddl.auto">update</property><!-- 让hibernate自动生成ddl -->
<property name="hibernate.show_sql">true</property>
<mapping resource="blog/hibernate/domain/User.hbm.xml"/>
</session-factory>

</hibernate-configuration>

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User.java

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package blog.hibernate.domain;

import java.util.Date;

public class User {
private int id;
private String name;
private Date birthday;

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;
}

}

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User.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 package="blog.hibernate.domain">
<class name="User" table="USERS">
<id name="id" column="USER_ID">
<generator class="native"></generator>
</id>
<property name="name" column="USER_NAME" type="string"></property>
<property name="birthday" column="BIRTHDAY" type="timestamp"></property>
</class>
</hibernate-mapping>

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HibernateUtil.java

**********************

package blog.hibernate;

import java.util.Date;
import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Restrictions;

import blog.hibernate.domain.User;

public final class HibernateUtil {

private static SessionFactory sessionFactory;
private HibernateUtil(){}

static{
Configuration cfg = new Configuration();
sessionFactory =  cfg.configure("hibernate.cfg.xml").buildSessionFactory();
}

public static SessionFactory getSessionFactory(){
return sessionFactory;
}

public static Session getSession(){
return sessionFactory.openSession();
}

public static Object get(Class clazz,int Id) throws Exception {
Session session = null;
Object object = null;
try {
session = getSession();
object = session.get(clazz, Id);
//object = session.load(class, userId);
return object;
} catch (HibernateException e) {
e.printStackTrace();
throw e;
}finally{
session.close();
}
}

public static void add(Object object) throws Exception {
Session session = null;
Transaction tx = null;
try {
session = getSession();
tx = session.beginTransaction();// 相当于tx =session.getTransaction();tx.begin();
session.save(object);
tx.commit();
} catch (HibernateException e) {
if (tx != null) {
tx.rollback();
}
throw e;
} finally {
if (session != null) {
session.close();
}
}
}

public static void update(Object object) throws Exception {
Session session = null;
Transaction tx = null;
try {
session = getSession();
tx = session.beginTransaction();// 相当于tx =session.getTransaction();tx.begin();
session.update(object);
tx.commit();
} catch (HibernateException e) {
if (tx != null) {
tx.rollback();
}
throw e;
} finally {
if (session != null) {
session.close();
}
}
}

public static void delete(Object object) throws Exception {
Session session = null;
Transaction tx = null;
try {
session = getSession();
tx = session.beginTransaction();// 相当于tx =session.getTransaction();tx.begin();
session.delete(object);
tx.commit();
} catch (HibernateException e) {
if (tx != null) {
tx.rollback();
}
throw e;
} finally {
if (session != null) {
session.close();
}
}
}

/**
* 用HQL实现
* @param username
* @return User
*/
public static User get(String username){
Session session = null;
try {
session = getSession();
//1、String hql = "from User as user where user.name = ?";//User 为类 而不是表名
String hql = "from User as user where user.name =:name";
Query query = session.createQuery(hql);
//1、query.setString(0, username);
query.setString("name", username);
User user = (User)query.uniqueResult();

List<User> users = query.list();

/*//用于分页，可以针对不同的数据库
query.setFirstResult(0);
query.setMaxResults(10);*/
return user;
} catch (HibernateException e) {
throw e;
} finally {
if (session != null) {
session.close();
}
}
}

/**
* 用Criteria接口实现
* @param username
* @return List<User>
*/
@SuppressWarnings("unchecked")
public static List<User> query(){
Session session = null;
try {
session = getSession();
Criteria criteria = session.createCriteria(User.class);
//criteria.add(Restrictions.eq("name",username));
criteria.add(Restrictions.lt("birthday", new Date()));

List<User> users = criteria.list();
/*//分页
criteria.setFirstResult(0);
criteria.setMaxResults(10);*/
return users;
} catch (HibernateException e) {
throw e;
} finally {
if (session != null) {
session.close();
}
}
}
}

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Base.java

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package blog.hibernate;

import java.util.Date;

import blog.hibernate.domain.User;

public class Base {

/**
* @param args
*/
public static void main(String[] args) {
List<User> users = HibernateUtil.query();
for (User user : users) {
System.out.println(user.getName());
System.out.println(users.size());
System.out.println("*****************************");
}
}

}