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;
     }
 }