Hibernate中"二级缓存"配置

实体类 ：

  package cn.happy.entity;
  public class Emp {
      private Integer empNo;
       private String empName;
      public Integer getEmpNo() {
          return empNo;
      }
      public void setEmpNo(Integer empNo) {
          this.empNo = empNo;
      }
      public String getEmpName() {
          return empName;
      }
     public void setEmpName(String empName) {
         this.empName = empName;
      }
  }

工具类：

1 package cn.happy.util;
 2
 3 import org.hibernate.Session;
 4 import org.hibernate.SessionFactory;
 5 import org.hibernate.cfg.Configuration;
 6
 7 public class HibernateUtil {
 8     private static final ThreadLocal sessionTL=new ThreadLocal();
 9     private static Configuration cf;
10     private static final SessionFactory factory;
11     static{
12         try {
13             cf=new Configuration().configure();
14             factory=cf.buildSessionFactory();
15         } catch (Exception e) {
16             throw new ExceptionInInitializerError(e);
17         }
18     }
19     public static Session getSession()
20     {
21         //sessionTL的get()方法根据当前线程返回其对应的线程内部变量，
22                 //也就是我们需要的Session，多线程情况下共享数据库连接是不安全的。
23                 //ThreadLocal保证了每个线程都有自己的Session。
24         Session session = (Session)sessionTL.get();
25         //如果session为null，则打开一个新的session
26         if (session==null) {
27             //创建一个数据库连接对象session
28             session=factory.openSession();
29             //保存该数据库连接session到ThreadLocal中。
30             sessionTL.set(session);
31
32         }
33         //如果当前线程已经访问过数据库了，
34                 //则从sessionTL中get()就可以获取该线程上次获取过的数据库连接对象。
35                 return session;
36     }
37     /**
38      * 关闭Session
39      */
40     public static void closeSession()
41     {
42         Session session =(Session)sessionTL.get();
43         sessionTL.set(null);
44         session.close();
45     }
46
47 }

测试类：

 package cn.happy.test;

 import org.hibernate.Session;
 import org.hibernate.Transaction;
 import org.junit.Test;

 import cn.happy.entity.Emp;
 import cn.happy.util.HibernateUtil;

 public class STest {
     Transaction tx;
     Session session;
     Transaction tx2;
     Session session2;
      @Test
        public void testBulk(){
             session = HibernateUtil.getSession();
             tx=session.beginTransaction();
            Emp emp = (Emp)session.get(Emp.class, 1);
            System.out.println(emp);
            tx.commit();
            HibernateUtil.closeSession();
            System.out.println("===================");
            session2 = HibernateUtil.getSession();
             tx2=session2.beginTransaction();
            Emp emp2 = (Emp)session2.get(Emp.class, 1);
            System.out.println(emp2);
            tx2.commit();
            HibernateUtil.closeSession();
        }
     }

小配置：

 <?xml version='1.0' encoding='utf-8'?>
 <!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.happy.entity">
      <class name="Emp" table="Emp">
      <cache usage="read-write"/>
          <id name="empNo" type="int" column="EMPNO">
          <generator class="native">
          </generator>
         </id>
          <property name="empName" type="string" column="EMPNAME"/>
      </class>
  </hibernate-mapping>

大配置：

 <?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>
     <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>
     <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
     <property name="connection.username">zc</property>
         <property name="connection.password">zc</property>
         <!-- 输出所有 SQL 语句到控制台。 -->
         <property name="hibernate.show_sql">true</property>
         <!-- 配置Hibernate.cfg.xml开启二级缓存。 -->
           <property name="hibernate.cache.use_second_level_cache">true</property>
           <!-- 配置二级缓存的供应商 -->
         <property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>

         <!-- 在 log 和 console 中打印出更漂亮的 SQL。 -->
         <property name="hibernate.format_sql">true</property>
         <!-- 自动生成数据表，update/create -->
         <property name="hbm2ddl.auto">update</property>
         <!-- 方言 -->
         <property name="hibernate.dialect">    org.hibernate.dialect.Oracle10gDialect</property>
         <!-- 关联小配置 -->

         <mapping resource="cn/happy/entity/Emp.hbm.xml"/>
         <class-cache    usage="read-write" class="cn.happy.entity.Emp"/>
     </session-factory>
     </hibernate-configuration>

Jar包导入：

package cn.happy.entity;
　　public class Emp {

　　　　private Integer empNo;

　　　　private String empName;

　　　　public Integer getEmpNo() {return empNo;}

　　　　public void setEmpNo(Integer empNo) {this.empNo = empNo;}

　　　　public String getEmpName() {return empName;}

　　　　public void setEmpName(String empName) {this.empName = empName;}
　　}