Hibernate初始化创建SessionFactory，Session，关闭SessonFactory，session

1.hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="dialect">
            org.hibernate.dialect.MySQLDialect</property>        <!-- 数据库方言 -->
        <property name="connection.url">
            jdbc:mysql://localhost:3306/db_examsystem</property><!-- 数据库连接URL -->
        <property name="connection.username">root</property>    <!-- 数据库用户名 -->
        <property name="connection.password">123456</property>    <!-- 数据库用户密码 -->
        <property name="connection.driver_class">                <!-- 数据库驱动类 -->
            com.mysql.jdbc.Driver</property>
        <mapping resource="com/sanqing/po/Student.hbm.xml"/>
        <mapping resource="com/sanqing/po/Teacher.hbm.xml"/>
        <mapping resource="com/sanqing/po/Subject.hbm.xml"/>    
    </session-factory>
</hibernate-configuration>

2.hibernateSessionFactory类

package com.sanqing.hibernate;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
import org.junit.Test;

public class HibernateSessionFactory {
    private static String CONFIG_FILE_LOCATION 
                    = "/hibernate.cfg.xml";                    //指定配置文件路径
    private static final ThreadLocal<Session> threadLocal 
                    = new ThreadLocal<Session>();            //定义ThreadLocal对象
    private  static Configuration configuration 
                    = new Configuration();                    //定义Configuration对象
    private static org.hibernate.SessionFactory sessionFactory;//定义SessionFactory对象
    private static String configFile = CONFIG_FILE_LOCATION;
    static {
        try {
            configuration.configure(configFile);//读取配置文件
            sessionFactory = 
                configuration.buildSessionFactory();//根据配置文件创建SessionFactory对象
        } catch (Exception e) {
            System.err
                    .println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }
    private HibernateSessionFactory() {
    }
    public static Session getSession() throws HibernateException {
        Session session = (Session) threadLocal.get();//从ThreadLocal对象中获得Session对象
        if (session == null || !session.isOpen()) {//判断获得的Session对象是否为空或者未打开
            if (sessionFactory == null) {//如果没有创建SessionFactory对象，则首先创建
//                rebuildSessionFactory();
            }
            //如果SessionFactory对象不为空，则调用其openSession方法创建Session对象
            session = (sessionFactory != null) ? sessionFactory.openSession(): null;
            threadLocal.set(session);//在ThreadLocal对象中保存该Session对象
        }
        return session;
    }
//    public static void rebuildSessionFactory() {
//        try {
//            configuration.configure(configFile);//读取配置文件
//            sessionFactory = 
//                configuration.buildSessionFactory();//根据配置文件创建sessionFactory对象
//        } catch (Exception e) {
//            System.err
//                    .println("%%%% Error Creating SessionFactory %%%%");
//            e.printStackTrace();
//        }
//    }
    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();//从ThreadLocal对象中获得Session对象
        threadLocal.set(null);//将当前线程Session对象从ThreadLocal对象中移除
        if (session != null) {
            session.close();
        }
    }
    public static org.hibernate.SessionFactory getSessionFactory() {//取得SessionFactory对象
        return sessionFactory;
    }
    public static void setConfigFile(String configFile) {//设置新的配置文件
        HibernateSessionFactory.configFile = configFile;
        sessionFactory = null;
    }
    public static Configuration getConfiguration() {//获得Configuration对象
        return configuration;
    }
}

3.student

package com.sanqing.po;
/*
 * 学生表,保存学生编号，系统密码
 */
public class Student {
    private String studentID;
    private String password;
    private String studentName;
    private Integer result;
    private String sclass;
    public String getStudentID() {
        return studentID;
    }
    public void setStudentID(String studentID) {
        this.studentID = studentID;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getStudentName() {
        return studentName;
    }
    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }
    public Integer getResult() {
        return result;
    }
    public void setResult(Integer result) {
        this.result = result;
    }
    public String getSclass() {
        return sclass;
    }
    public void setSclass(String sclass) {
        this.sclass = sclass;
    }
}

4.student.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping 
            PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="com.sanqing.po.Student" table="tb_student"><!-- 每个class对应一个持久化对象 -->
        <id name="studentID" type="string"><!-- id元素用来定义主键标识,并指定主键生成策略 -->
            <generator class="assigned"></generator>
        </id>
        <property name="password" type="string"></property><!-- 映射password属性 -->
        <property name="studentName" type="string"></property><!-- 映射studentName属性 -->
        <property name="result" type="int"></property><!-- 映射result属性 -->
        <property name="sclass" type="string"></property><!-- 映射sclass属性 -->
    </class>    
</hibernate-mapping>

5.studentDao

package com.sanqing.dao;

import java.util.List;

import com.sanqing.po.Student;

public interface StudentDAO {
    public Student findByStudentID(String studentID);//查询方法，根据学生ID查询
    public void updateStudent(Student student);//更新学生信息
    public List<Student> findByStudentName(String studentName);//根据学生姓名查找学生
    public List<Student> findByStudentClass(String sclass);//根据班级查找学生
}

6.studentDaoImpl

package com.sanqing.dao;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

import com.sanqing.hibernate.HibernateSessionFactory;
import com.sanqing.po.Student;
import com.sanqing.po.Subject;

public class StudentDAOImpl implements StudentDAO{
    public Student findByStudentID(String studentID) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Student student = (Student) session.get(Student.class, studentID);
        HibernateSessionFactory.closeSession();//关闭Session对象
        return student;
    }

    public void updateStudent(Student student) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Transaction  transaction = null;//声明一个事务对象
        try{
            transaction = session.beginTransaction();//开启事务
            session.update(student);//更新学生信息
            transaction.commit();//提交事务
        }catch(Exception ex) {
            ex.printStackTrace();
            transaction.rollback();//事务回滚
        }
        HibernateSessionFactory.closeSession();//关闭Session对象
    }

    public List<Student> findByStudentName(String studentName) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Query query = session.createQuery("from Student as stu where stu.studentName = ?");
        query.setString(0, studentName);
        List list = query.list();                    //查询结果保存到list中
        HibernateSessionFactory.closeSession();        //关闭Session对象
        return list;
    }

    public List<Student> findByStudentClass(String sclass) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Query query = session.createQuery("from Student as stu where stu.sclass = ?");
        query.setString(0, sclass);
        List list = query.list();                    //查询结果保存到list中
        HibernateSessionFactory.closeSession();        //关闭Session对象
        return list;
    }
}

package com.sanqing.dao;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

import com.sanqing.hibernate.HibernateSessionFactory;
import com.sanqing.po.Student;
import com.sanqing.po.Subject;

public class StudentDAOImpl implements StudentDAO{
    public Student findByStudentID(String studentID) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Student student = (Student) session.get(Student.class, studentID);
        HibernateSessionFactory.closeSession();//关闭Session对象
        return student;
    }

    public void updateStudent(Student student) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Transaction  transaction = null;//声明一个事务对象
        try{
            transaction = session.beginTransaction();//开启事务
            session.update(student);//更新学生信息
            transaction.commit();//提交事务
        }catch(Exception ex) {
            ex.printStackTrace();
            transaction.rollback();//事务回滚
        }
        HibernateSessionFactory.closeSession();//关闭Session对象
    }

    public List<Student> findByStudentName(String studentName) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Query query = session.createQuery("from Student as stu where stu.studentName = ?");
        query.setString(0, studentName);
        List list = query.list();                    //查询结果保存到list中
        HibernateSessionFactory.closeSession();        //关闭Session对象
        return list;
    }

    public List<Student> findByStudentClass(String sclass) {
        Session session = HibernateSessionFactory.getSession();//获得Session对象
        Query query = session.createQuery("from Student as stu where stu.sclass = ?");
        query.setString(0, sclass);
        List list = query.list();                    //查询结果保存到list中
        HibernateSessionFactory.closeSession();        //关闭Session对象
        return list;
    }
}