29hibernate_query_cache
hibernate查询缓存
查询缓存是针对普通属性结果集的缓存
对实体对象的结果集只缓存id
查询缓存的生命周期(不确定)，当前关联的表发生修改，那么查询缓存生命周期结束
查询缓存的配置和使用：
* 在hibernate.cfg.xml文件中启用查询缓存，如：
<property name="hibernate.cache.use_query_cache">true</property>
* 在程序中必须手动启用查询缓存，如：
query.setCacheable(true);
<!-- 开启二级缓存 -->
<property name="hibernate.cache.use_second_level_cache">true</property>
<!-- 指定缓存产品提供商 -->
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<!-- 启用查询缓存 -->
<property name="hibernate.cache.use_query_cache">true</property>
<class-cache class="com.bjsxt.hibernate.Student" usage="read-only"/>
=======================================================
package com.bjsxt.hibernate;
import java.io.Serializable;
import java.util.Iterator;
import java.util.List;
import org.hibernate.CacheMode;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import junit.framework.TestCase;
public class QueryCacheTest extends TestCase {
/**
* 开启查询缓存，关闭二级缓存
*
* 开启一个session，分别调用query.list
*/
public void testCache1() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
List names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
System.out.println("-------------------------------------");
query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
//没有发出查询sql，因为启用了查询缓存
names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.list
* 在两个session中，不影响查询缓存，也就是说session与查询缓存的生命周期没有关系
*/
public void testCache2() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
List names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
//不会发出查询sql，因为查询缓存的生命周期和session无关
List names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.iterate
*/
public void testCache3() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
for (Iterator iter=query.iterate();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
//查询缓存只对query.list()起作用，query.iterate不起作用，也就是query.iterate不使用
//查询缓存
for (Iterator iter=query.iterate();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 关闭查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.list查询实体对象
*/
public void testCache4() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
//会发出查询sql，因为list默认每次都会发出查询sql
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.list查询实体对象
*/
public void testCache5() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
//会发出n条查询语句，因为开启了查询缓存，关闭了二级缓存，那么查询缓存会缓存实体对象的id
//所以hibernate会根据实体对象的id去查询相应的实体，如果缓存中不存在相应的
//实体那么将发出根据实体id查询的sql语句，否则不会发出sql使用缓存中的数据
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，开启二级缓存
*
* 开启两个session，分别调用query.list查询实体对象
*/
public void testCache6() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
//不会发出查询sql，因为开启了二级缓存和查询缓存，查询缓存缓存了实体对象的id列表
//hibernate会根据实体对象的id列表到二级缓存中取得相应的数据
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
}
======================================================
==========================查询变通属性==================
Test1: 关闭查询缓存，关闭二级缓存,开启一个session，分别调用query.list
<property name="hibernate.cache.use_second_level_cache">false</property>
<property name="hibernate.cache.use_query_cache">false</property>
//query.setCacheable(true);
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
-------------------------------------
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
Test2: 开启查询缓存，关闭二级缓存,开启一个session，分别调用query.list
<property name="hibernate.cache.use_query_cache">true</property>
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
班级0的学生0
班级0的学生1
....
s_999
-------------------------------------
班级0的学生0
班级0的学生1
......
结论：查询缓存是针对普通属性结果集的缓存，它的生命周期不可控制，所以它的利用率不高
Test2:在两个session中，不影响查询缓存，也就是说session与查询缓存的生命周期没有关系
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
班级0的学生0
班级0的学生1
....
s_999
-------------------------------------
班级0的学生0
班级0的学生1
......
Test4:关闭查询缓存，关闭二级缓存, 开启两个session，分别调用query.iterate
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
-------------------------------------
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
Test5: 开启查询缓存，关闭二级缓存, 开启两个session，分别调用query.iterate
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
-------------------------------------
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
结论：查询缓存对iterate不起作用！
//查询缓存只对query.list()起作用，query.iterate不起作用，也就是query.iterate不使用查询缓存
==========================查询实体对象==================
Test6:关闭查询缓存，关闭二级缓存,开启两个session，分别调用query.list查询实体对象
Hibernate: select student0_.id as id1_, student0_.name as name1_, student0_.classesid as classesid1_ from t_student student0_
班级0的学生0
班级0的学生1
... ...
s_999
-------------------------------------
Hibernate: select student0_.id as id1_, student0_.name as name1_, student0_.classesid as classesid1_ from t_student student0_
班级0的学生0
班级0的学生1
结论：会发出查询sql，因为list默认每次都会发出查询sql
Test7:开启查询缓存，关闭二级缓存,开启两个session，分别调用query.list查询实体对象
发出N条
Hibernate select student0_.id as id1_0_, student0_.name as name1_0_, student0_.classesid as classesid1_0_ from t_student student0_ where student0_.id=?
结论：两个session，二级缓存关闭着：
//会发出n条查询语句，因为开启了查询缓存，关闭了二级缓存，那么查询缓存会缓存实体对象的id
//所以hibernate会根据实体对象的id去查询相应的实体，如果缓存中不存在相应的实体，那么将发出根据实体id查询的sql语句，否则不会发出sql使用缓存中的数据
Test8:开启查询缓存，开启二级缓存， 开启两个session，分别调用query.list查询实体对象
Hibernate: select student0_.id as id1_, student0_.name as name1_, student0_.classesid as classesid1_ from t_student student0_
班级0的学生0
班级0的学生1
... ...
s_999
-------------------------------------
班级0的学生0
班级0的学生1
... ...
s_999
结论：//不会发出查询sql，因为开启了二级缓存和查询缓存，查询缓存缓存了实体对象的id列表
//hibernate会根据实体对象的id列表到二级缓存中取得相应的数据
查询缓存是针对普通属性结果集的缓存
对实体对象的结果集只缓存id
查询缓存的生命周期(不确定)，当前关联的表发生修改，那么查询缓存生命周期结束
查询缓存的配置和使用：
* 在hibernate.cfg.xml文件中启用查询缓存，如：
<property name="hibernate.cache.use_query_cache">true</property>
* 在程序中必须手动启用查询缓存，如：
query.setCacheable(true);
<!-- 开启二级缓存 -->
<property name="hibernate.cache.use_second_level_cache">true</property>
<!-- 指定缓存产品提供商 -->
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<!-- 启用查询缓存 -->
<property name="hibernate.cache.use_query_cache">true</property>
<class-cache class="com.bjsxt.hibernate.Student" usage="read-only"/>
=======================================================
package com.bjsxt.hibernate;
import java.io.Serializable;
import java.util.Iterator;
import java.util.List;
import org.hibernate.CacheMode;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import junit.framework.TestCase;
public class QueryCacheTest extends TestCase {
/**
* 开启查询缓存，关闭二级缓存
*
* 开启一个session，分别调用query.list
*/
public void testCache1() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
List names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
System.out.println("-------------------------------------");
query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
//没有发出查询sql，因为启用了查询缓存
names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.list
* 在两个session中，不影响查询缓存，也就是说session与查询缓存的生命周期没有关系
*/
public void testCache2() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
List names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
//不会发出查询sql，因为查询缓存的生命周期和session无关
List names = query.list();
for (Iterator iter=names.iterator();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.iterate
*/
public void testCache3() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
for (Iterator iter=query.iterate();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s.name from Student s");
//启用查询查询缓存
query.setCacheable(true);
//查询缓存只对query.list()起作用，query.iterate不起作用，也就是query.iterate不使用
//查询缓存
for (Iterator iter=query.iterate();iter.hasNext(); ) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 关闭查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.list查询实体对象
*/
public void testCache4() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
//会发出查询sql，因为list默认每次都会发出查询sql
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，关闭二级缓存
*
* 开启两个session，分别调用query.list查询实体对象
*/
public void testCache5() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
//会发出n条查询语句，因为开启了查询缓存，关闭了二级缓存，那么查询缓存会缓存实体对象的id
//所以hibernate会根据实体对象的id去查询相应的实体，如果缓存中不存在相应的
//实体那么将发出根据实体id查询的sql语句，否则不会发出sql使用缓存中的数据
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 开启查询缓存，开启二级缓存
*
* 开启两个session，分别调用query.list查询实体对象
*/
public void testCache6() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
System.out.println("-------------------------------------");
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Query query = session.createQuery("select s from Student s");
//启用查询查询缓存
query.setCacheable(true);
//不会发出查询sql，因为开启了二级缓存和查询缓存，查询缓存缓存了实体对象的id列表
//hibernate会根据实体对象的id列表到二级缓存中取得相应的数据
List students = query.list();
for (Iterator iter=students.iterator();iter.hasNext(); ) {
Student student = (Student)iter.next();
System.out.println(student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
}
======================================================
==========================查询变通属性==================
Test1: 关闭查询缓存，关闭二级缓存,开启一个session，分别调用query.list
<property name="hibernate.cache.use_second_level_cache">false</property>
<property name="hibernate.cache.use_query_cache">false</property>
//query.setCacheable(true);
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
-------------------------------------
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
Test2: 开启查询缓存，关闭二级缓存,开启一个session，分别调用query.list
<property name="hibernate.cache.use_query_cache">true</property>
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
班级0的学生0
班级0的学生1
....
s_999
-------------------------------------
班级0的学生0
班级0的学生1
......
结论：查询缓存是针对普通属性结果集的缓存，它的生命周期不可控制，所以它的利用率不高
Test2:在两个session中，不影响查询缓存，也就是说session与查询缓存的生命周期没有关系
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
班级0的学生0
班级0的学生1
....
s_999
-------------------------------------
班级0的学生0
班级0的学生1
......
Test4:关闭查询缓存，关闭二级缓存, 开启两个session，分别调用query.iterate
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
-------------------------------------
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
Test5: 开启查询缓存，关闭二级缓存, 开启两个session，分别调用query.iterate
测试结果：
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
-------------------------------------
Hibernate: select student0_.name as col_0_0_ from t_student student0_
....
s_999
结论：查询缓存对iterate不起作用！
//查询缓存只对query.list()起作用，query.iterate不起作用，也就是query.iterate不使用查询缓存
==========================查询实体对象==================
Test6:关闭查询缓存，关闭二级缓存,开启两个session，分别调用query.list查询实体对象
Hibernate: select student0_.id as id1_, student0_.name as name1_, student0_.classesid as classesid1_ from t_student student0_
班级0的学生0
班级0的学生1
... ...
s_999
-------------------------------------
Hibernate: select student0_.id as id1_, student0_.name as name1_, student0_.classesid as classesid1_ from t_student student0_
班级0的学生0
班级0的学生1
结论：会发出查询sql，因为list默认每次都会发出查询sql
Test7:开启查询缓存，关闭二级缓存,开启两个session，分别调用query.list查询实体对象
发出N条
Hibernate select student0_.id as id1_0_, student0_.name as name1_0_, student0_.classesid as classesid1_0_ from t_student student0_ where student0_.id=?
结论：两个session，二级缓存关闭着：
//会发出n条查询语句，因为开启了查询缓存，关闭了二级缓存，那么查询缓存会缓存实体对象的id
//所以hibernate会根据实体对象的id去查询相应的实体，如果缓存中不存在相应的实体，那么将发出根据实体id查询的sql语句，否则不会发出sql使用缓存中的数据
Test8:开启查询缓存，开启二级缓存， 开启两个session，分别调用query.list查询实体对象
Hibernate: select student0_.id as id1_, student0_.name as name1_, student0_.classesid as classesid1_ from t_student student0_
班级0的学生0
班级0的学生1
... ...
s_999
-------------------------------------
班级0的学生0
班级0的学生1
... ...
s_999
结论：//不会发出查询sql，因为开启了二级缓存和查询缓存，查询缓存缓存了实体对象的id列表
//hibernate会根据实体对象的id列表到二级缓存中取得相应的数据
========================================hibernate.cfg.xml===========================================================
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.url">jdbc:mysql://localhost/hibernate_cache</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.show_sql">true</property>
<!-- 开启二级缓存 -->
<property name="hibernate.cache.use_second_level_cache">true</property>
<!-- 指定缓存产品提供商 -->
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<!-- 启用查询缓存 -->
<property name="hibernate.cache.use_query_cache">true</property>
<mapping resource="com/bjsxt/hibernate/Classes.hbm.xml"/>
<mapping resource="com/bjsxt/hibernate/Student.hbm.xml"/>
<class-cache class="com.bjsxt.hibernate.Student" usage="read-only"/>
</session-factory>
</hibernate-configuration>
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.url">jdbc:mysql://localhost/hibernate_cache</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.show_sql">true</property>
<!-- 开启二级缓存 -->
<property name="hibernate.cache.use_second_level_cache">true</property>
<!-- 指定缓存产品提供商 -->
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<!-- 启用查询缓存 -->
<property name="hibernate.cache.use_query_cache">true</property>
<mapping resource="com/bjsxt/hibernate/Classes.hbm.xml"/>
<mapping resource="com/bjsxt/hibernate/Student.hbm.xml"/>
<class-cache class="com.bjsxt.hibernate.Student" usage="read-only"/>
</session-factory>
</hibernate-configuration>
