package myHibernate;
import java.io.Serializable;
import myHibernate.HibernateUtils;
import myHibernate.Student;
import org.hibernate.CacheMode;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import junit.framework.TestCase;
public class CacheLevel2Test extends TestCase {
/**
* 开启个session，分别调用load
* 先将二级缓存设为false，也就是只使用session级的缓存，即不能跨session访问缓存，
* 所以会发出两次SQL语句；
* 然后将二级缓存设为true,可以debug观察发现只发出了一次SQL语句
*/
public void testCache1() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
//第二个session
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
//用get方法，也是一样支持缓存的，所以结果是一样的
public void testCache2() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Student student = (Student)session.get(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
//第二个session
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Student student = (Student)session.get(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启个session，分别调用load,第一个调用完之后便使用evict管理二级缓存，
* evict可以将某个类的所有缓存都清除，也可以只清除某一个对象，这时候要指明
* id
* */
public void testCache3() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
SessionFactory sf = HibernateUtils.getSessionFactory();
//清除该类的所有对象
//sf.evict(Student.class);
//清除某个特定对象
sf.evict(Student.class, 1);
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* session与二级缓存的交互
* */
public void testCache4() {
Session session = null;
//第一个session
try {
session = HibernateUtils.getSession();
session.beginTransaction();
/*
* 设置CacheMode
* CacheMode.NORMAL :从二级缓存中读、写数据
* CacheMode.GET : 从二级缓存中读取数据，仅在数据更新时对二级缓存写数据
* CacheMode.PUT : 仅向二级缓存写数据，但不从二级缓存度数据
* */
System.out.println("第一个session");
session.setCacheMode(CacheMode.GET);
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
SessionFactory sf = HibernateUtils.getSessionFactory();
//第二个session，不设置CacheMode,为默认状态，即会读、写缓存
try {
session = HibernateUtils.getSession();
session.beginTransaction();
//会发出SQL语句，因为第一个session设置CacheMode.GET
System.out.println("第二个session");
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
//第三个session,不设置CacheMode
try {
session = HibernateUtils.getSession();
session.beginTransaction();
System.out.println("第三个session");
//不会发错SQL语句，因为因为第二个session没有设置CacheMode，则缓存里有数据
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
//第四个session ，将CacheMode设置为PUT，即只写不读
try {
session = HibernateUtils.getSession();
session.beginTransaction();
System.out.println("第四个session");
//会发出SQL语句，因为CacheMode设置为PUT，虽然缓存里有数据但不读取
session.setCacheMode(CacheMode.PUT);
Student student = (Student)session.load(Student.class, 1);
System.out.println("student.name=" + student.getName());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
}