import java.io.Serializable;

import org.hibernate.Session;

import junit.framework.TestCase;

public class CacheLevel1Test extends TestCase {

/**

* 在同一个session中发出两次load查询

*/

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());

//不会发出sql，因为load使用缓存

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);

}

}

/**

* 在同一个session中发出两次get查询

*/

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());

//不会发出sql，因为get使用缓存

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);

}

}

/**

* 在同一个session中发出两次iterate查询实体对象

*/

public void testCache3() {

Session session = null;

try {

session = HibernateUtils.getSession();

session.beginTransaction();

Student student = (Student)session.createQuery("from Student s where s.id=1").iterate().next();

System.out.println("student.name=" + student.getName());

//会发出查询id的sql，不会发出查询实体对象的sql，因为iterate使用缓存

student = (Student)session.createQuery("from Student s where s.id=1").iterate().next();

System.out.println("student.name=" + student.getName());

session.getTransaction().commit();

}catch(Exception e) {

e.printStackTrace();

session.getTransaction().rollback();

}finally {

HibernateUtils.closeSession(session);

}

}

/**

* 在同一个session中发出两次iterate查询实体对象

*/

public void testCache4() {

Session session = null;

try {

session = HibernateUtils.getSession();

session.beginTransaction();

//查询属性而不是实体，故不会在一级缓存中写入数据

String name = (String)session.createQuery("select s.name from Student s where s.id=1").iterate().next();

System.out.println("student.name=" + name);

//iterate查询普通属性，一级缓存不会缓存，所以发出sql

//一级缓存是缓存实体对象的

name = (String)session.createQuery("select s.name from Student s where s.id=1").iterate().next();

System.out.println("student.name=" + name);

session.getTransaction().commit();

}catch(Exception e) {

e.printStackTrace();

session.getTransaction().rollback();

}finally {

HibernateUtils.closeSession(session);

}

}

/**

* 开启两个session中发出load查询

*/

public void testCache5() {

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);

}

try {

session = HibernateUtils.getSession();

session.beginTransaction();

//会发出查询语句，session间不能共享一级缓存的数据

//因为它会伴随session的生命周期存在和消亡

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);

}

}

/**

* 在同一个session中先save，在发出load查询save过的数据

*/

public void testCache6() {

Session session = null;

try {

session = HibernateUtils.getSession();

session.beginTransaction();

Student stu = new Student();

stu.setName("王五");

Serializable id = session.save(stu);

//不会发出sql，因为save是使用缓存的

Student student = (Student)session.load(Student.class, id);

System.out.println("student.name=" + student.getName());

session.getTransaction().commit();

}catch(Exception e) {

e.printStackTrace();

session.getTransaction().rollback();

}finally {

HibernateUtils.closeSession(session);

}

}

/**

* 向数据库中批量加入1000条数据

*/

public void testCache7() {

Session session = null;

try {

session = HibernateUtils.getSession();

session.beginTransaction();

for (int i=0; i<1000; i++) {

Student student = new Student();

student.setName("s_" + i);

session.save(student);

//每20条数据就强制session将数据持久化

//同时清除缓存，避免大量数据造成内存溢出

if ( i % 20 == 0) {

session.flush();

session.clear();

}

}

session.getTransaction().commit();

}catch(Exception e) {

e.printStackTrace();

session.getTransaction().rollback();

}finally {

HibernateUtils.closeSession(session);

}

}

}