Hibernate-------<1>初步学习

Hibernate-------<1>初步学习
javaBean------Student.java              数据库-----students表
public class Student {                      create database hib character set utf8;     
 private String studId;              use hib;
 private String studName;             create table students(
 private Integer studAge;             id varchar(8) primary key,
 private String deptId;               name varchar(40),
 public String getStudId() {          age int,
  return studId;               deptId varchar(8)  );
 }                         
 public void setStudId(String studId) {
  this.studId = studId;
 }
 public String getStudName() {
  return studName;
 }
 public void setStudName(String studName) {
  this.studName = studName;
 }
 public Integer getStudAge() {
  return studAge;
 }
 public void setStudAge(Integer studAge) {
  this.studAge = studAge;
 }
 
 public String getDeptId() {
  return deptId;
 }
 public void setDeptId(String deptId) {
  this.deptId = deptId;
 }
 
}

mapping file------Student.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="cn.hncu.demo.domain">
<!--要配置对象所在的包 -->
 <class name="Student" table="students" catalog="hib">
  <!--catalog 指定数据库-->
  <id name="studId" type="java.lang.String">
  <!-- 只有主键字段对应的属性变量才能用id，其它字段对应的属性变量都用property -->
   <column name="id" length="8"></column>
  </id>
  <property name="studName" type="java.lang.String">
   <column name="name" length="40"></column>
  </property>
  <property name="studAge" type="java.lang.Integer">
   <column name="age"></column>
  </property>
  <property name="deptId" type="java.lang.String">
   <column name="deptId" length="8"></column>
  </property>
 </class>
</hibernate-mapping>

Hibernate configuration----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>
 <!--  有关的数据库连接  Database connection settings -->
  <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
  <property name="connection.url">jdbc:mysql://127.0.0.1:3306/hib</property>
  <property name="connection.username">root</property>
  <property name="connection.password">1234</property>
 <!-- 设置Dialect -->
  <property name="dialect">
   org.hibernate.dialect.MySQLDialect
  </property>
 <!-- 把mapping file 配置进来 -->
  <mapping resource="cn/hncu/demo/domain/Student.hbm.xml"/>
 </session-factory>
</hibernate-configuration>

写一个工具类拿Session-----HibernateSessionFactory.java
public class HibernateSessionFactory {
 private static SessionFactory sessionFactory=null;
 private static ThreadLocal<Session> t=new ThreadLocal<Session>();
 
 static{
  try {
   Configuration config=new Configuration().configure();
   StandardServiceRegistry serviceRegistry=new

StandardServiceRegistryBuilder().applySettings(config.getProperties()).build();
   sessionFactory=config.buildSessionFactory(serviceRegistry);
  } catch (Throwable ex) {
   throw new ExceptionInInitializerError(ex);
  }
 }
 
 public static SessionFactory getSessionFactory() {
  return sessionFactory;
 }
 public static Session getSession(){
  Session session=t.get();
  if(session==null||session.isOpen()){
   session = (sessionFactory!=null)? sessionFactory.openSession():

null;
   t.set(session);
  }
  return session;
 } 
 public static void clear(){
  t.set(null);
 }
}
测试类------StudentManager.java
public class StudentManager {
 public static void main(String[] args) {
  Session session=HibernateSessionFactory.getSession();
  //开启事务
  session.beginTransaction();
  
  Student stud=new Student();
  stud.setStudId("S006");
  stud.setStudName("刘备");
  stud.setStudAge(23);
  stud.setDeptId("D003");
  session.save(stud);
  
  Student stud2=new Student();
  stud2.setStudId("S007");
  stud2.setStudName("刘三");
  stud2.setStudAge(26);
  stud2.setDeptId("D004");
  session.save(stud2);//
  
  session.getTransaction().commit();//事务提交；如果出异常Hibernate会帮我们

回滚的，我们不用写rollback() ；
  //session.close();Hibernate中session是不能关,也关不了
 }  
}