一、Hibernate入门案例剖析：

①创建实体类Student 并重写toString方法

public class Student {    private Integer sid;    private Integer age; private String name; public Integer getSid() { return sid; } public void setSid(Integer sid) { this.sid = sid; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public String toString() { return "Student [sid=" + sid + ", age=" + age + ", name=" + name + "]"; } }

② 创建学生对象 并赋值

 

③引入jar包

④ 构建大配置<hibernate.cfg.xml>

可分为以下步骤：

1.连接数据库的语句

2.sql方言

3.可省的配置(show_sql、format_sql 取值为true)

4.让程序生成底层数据表(hbm2ddl.auto) update/create。create是每次将数据表删除后，重新创建

5.关联小配置

<mapping resource="cn/happy/entity/Student.hbm.xml" />

关键代码如下：

       
           
                
                 
                 
         
          oracle.jdbc.OracleDriver
                 
                 
         
          jdbc:oracle:thin:@localhost:1521:orcl3
                 
         
          wj
                 
         
          9090
                 
                 
         
          org.hibernate.dialect.Oracle10gDialect
                 
                 
         
          true
                                 
                 
                                 
                  
         
          update
                   
                 
                 
                     
        
       

⑤ 构建小配置(Student.hbm.xml)

       
               
                
                    
           
           
           SEQ_NUM 
           
          
          
          
          
         
       

⑥ 工具类HibernateUtil、构建私有静态的Configuration、SessionFactory对象、定义返回session以及关闭session的方法

private static Configuration cf=new Configuration().configure();    private static SessionFactory sf=cf.buildSessionFactory(); //方法返回session public static Session getSession(){ return sf.openSession(); } //关闭Session public static void CloseSession(){ getSession().close(); }

⑦测试类【增删改查】 使用标记After、Before可简化代码

package cn.happy.test;import org.hibernate.Session;import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.cfg.Configuration; import org.junit.After; import org.junit.Before; import org.junit.Test; import cn.happy.entity.Student; import cn.happy.util.HibernateUtil; public class Test1 { Session session; Transaction tx; @After public void afterTest(){ tx.commit(); HibernateUtil.CloseSession(); } @Before public void initData(){ session=HibernateUtil.getSession(); tx=session.beginTransaction(); } /* * get方法查询 */ @Test public void getData(){ Student stu=(Student)session.get(Student.class, 3); System.out.println(stu); } /* * 增加 */ @Test public void addData(){ Student stu=new Student(); stu.setSid(12); stu.setAge(11); stu.setName("李小龙1"); //读取大配置文件 获取连接信息 Configuration cfg=new Configuration().configure(); //创建SessionFactory SessionFactory fa=cfg.buildSessionFactory(); //加工Session Session se=fa.openSession(); Transaction tx = se.beginTransaction(); //保存 se.save(stu); //事务提交 tx.commit(); se.close(); System.out.println("Save ok!"); } /* * 删除 */ @Test public void delData(){ Session session=HibernateUtil.getSession(); Student stu=new Student(); stu.setSid(2); Transaction tx=session.beginTransaction(); session.delete(stu); tx.commit(); HibernateUtil.CloseSession(); System.out.println("del ok!"); } /* * 修改 */ @Test public void updateData(){ Session session=HibernateUtil.getSession(); Student stu=(Student)session.load(Student.class,3); stu.setName("呵呵"); Transaction tx=session.beginTransaction(); session.update(stu); tx.commit(); HibernateUtil.CloseSession(); System.out.println("update ok!"); } }