Spring缓存简单介绍（Spring Cache）

对spring Cache做了个了解，性能非常强悍。而且使用非常简答。下面有各个部分完整的代码。处理缓存的主要逻辑再ServiceImpl中！！

先看下不使用spring Cache查询10次所发出的语句

第1次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第2次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第3次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第4次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第5次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第6次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第7次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第8次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第9次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第10次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?

再看下使用spring Cache后查询10次所发出的语句

第1次查询Hibernate: select student0_.Id as Id0_, student0_.name as name0_, student0_.addr as addr0_ from student student0_ where student0_.Id=?第2次查询第3次查询第4次查询第5次查询第6次查询第7次查询第8次查询第9次查询第10次查询

可见效率提高不少。

首先要把spring常见的几个包导入到项目中

spring 3.1 以上，都支持 spring cache。其中 spring-context-*.jar 包含了 cache 需要的类。

Dao:

package com.ibm.bmcc.qixin.redis.dao;import javax.annotation.Resource;import org.apache.commons.lang.StringUtils;import org.hibernate.Query;import org.hibernate.SessionFactory;import org.springframework.orm.hibernate3.support.HibernateDaoSupport;import org.springframework.stereotype.Repository;import com.ibm.bmcc.qixin.redis.model.Student;/** * 缓存测试   dao * @author zhoudong * */@Repositorypublic class StudentDao extends HibernateDaoSupport{@Resource(name = "sessionFactory")// 注入 按名称装配public void setSuperSessionFactory(SessionFactory sessionFactory) {super.setSessionFactory(sessionFactory);}/** * 获取Student实体，String Cache测试 * @param id * @return */public Student getStudent(String id){String hql = "from Student where id = ?";return (Student) getHibernateTemplate().find(hql, id).get(0);}/** * 缓存更新 * @param student */public void updateStudent(Student student) {StringBuilder hql = new StringBuilder("update Student set");if(StringUtils.isNotBlank(student.getName())){hql.append(" name='");hql.append(student.getName()).append("'");}if(StringUtils.isNotBlank(student.getAddr())){hql.append(", addr = ");hql.append(student.getAddr());}hql.append("where id = '").append(student.getId()).append("'");Query query = getSession().createQuery(hql.toString());query.executeUpdate();}}

Service:

package com.ibm.bmcc.qixin.redis.service;import org.springframework.stereotype.Service;import com.ibm.bmcc.qixin.redis.model.Student;/** * redis测试 * @author zhoudong * */@Servicepublic interface StudentService {/** * 缓存测试 * @param id * @return */public Student getStudent(String id);/** * 更新缓存测试 * @param student * @return */public void updateStudent(Student student);/** * 清空缓存 */public void reload();}

ServiceImpl:

package com.ibm.bmcc.qixin.redis.service.impl;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.cache.annotation.CacheEvict;import org.springframework.cache.annotation.Cacheable;import org.springframework.stereotype.Service;import com.ibm.bmcc.qixin.redis.dao.StudentDao;import com.ibm.bmcc.qixin.redis.model.Student;import com.ibm.bmcc.qixin.redis.service.StudentService;@Servicepublic class StudentServiceImpl implements StudentService{@Resourceprivate StudentDao studentDao;@Cacheable(value="redisCache")// 使用了一个缓存名叫 redisCache public Student getStudent(String id) {return studentDao.getStudent(id);}@CacheEvict(value="redisCache",key="#student.getName()")//更新缓存public void updateStudent(Student student) {studentDao.updateStudent(student);}@CacheEvict(value="redisCache",allEntries=true)//清空缓存public void reload() {}}

# 号代表这是一个 SpEL 表达式，此表达式可以遍历方法的参数对象，具体语法可以参考 Spring 的相关文档手册。

value是必须参数，类似于存在哪个缓存，key是可选参数，默认是空，

action:

package com.ibm.bmcc.qixin.redis.view;import java.util.HashMap;import java.util.Map;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.servlet.ModelAndView;import com.ibm.bmcc.qixin.redis.model.Student;import com.ibm.bmcc.qixin.redis.service.StudentService;/** * cache 测试action * @author zhoudong * */@Controllerpublic class RedisAction {@Autowiredprivate StudentService studentService;/** * 缓存测试 * @return */@RequestMapping("redisCache")public @ResponseBody Map<String, String> redisCache(){Student student = null;for(int i=0; i<10; i++){System.out.println("第" + (i + 1) + "次查询");student = studentService.getStudent("qwqw");}Map<String,String> mav = new HashMap<String, String>();mav.put("name", student.getName());mav.put("addr", student.getAddr());return mav;}/** * 更新缓存 * @return */@RequestMapping("updateCache")public @ResponseBody Map<String, String> updateCache(){Student student = null;Student students = new Student();students.setName("mmm");students.setId("qwqw");studentService.updateStudent(students);student = studentService.getStudent("qwqw");Map<String,String> mav = new HashMap<String, String>();mav.put("name", student.getName());mav.put("addr", student.getAddr());return mav;}/** * 清空缓存 * @return */@RequestMapping("reload")public @ResponseBody Map<String, String> reload(){studentService.reload(); //清空缓存后再请求10次Student student = null;for(int i=0; i<10; i++){System.out.println("第" + (i + 1) + "次查询");student = studentService.getStudent("qwqw");}Map<String,String> mav = new HashMap<String, String>();mav.put("name", student.getName());mav.put("addr", student.getAddr());return mav;}}

既然是spring Cache 配置文件肯定是少不了的。。

<?xml version="1.0" encoding="UTF-8"?><beans     xmlns="http://www.springframework.org/schema/beans"    xmlns:aop="http://www.springframework.org/schema/aop"    xmlns:context="http://www.springframework.org/schema/context"    xmlns:mvc="http://www.springframework.org/schema/mvc"    xmlns:tx="http://www.springframework.org/schema/tx"    xmlns:cache="http://www.springframework.org/schema/cache"    xmlns:p="http://www.springframework.org/schema/p"    xsi:schemaLocation="        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd         http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd         http://www.springframework.org/schema/cache         http://www.springframework.org/schema/cache/spring-cache.xsd"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><!-- cache  start --><cache:annotation-driven /><!-- 缓存必须用的，启用缓存 --><bean id="studentService" class="com.ibm.bmcc.qixin.redis.service.impl.StudentServiceImpl"/>      <!-- generic cache manager -->    <bean id="cacheManager"    class="org.springframework.cache.support.SimpleCacheManager">     <property name="caches">        <set>          <bean            class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean"           p:name="default" />                  <bean            class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean"           p:name="redisCache" />        </set>      </property>    </bean> <!-- cache end --></beans>

<cache:annotation-driven />启动缓存 必配参数

刚开始了解，初步了解了下简单的，明天会做下更复杂的，请关注下一篇博客。

最终目的是为了spring Cache 和redis结合使用。