Spring实战之Cache

springcachecachingexceptionuseraop


这里假定我们已经有了一些现成的类和接口，比如说

1> 一个现成的User POJO对象

2> 一个UserDao接口和UserDaoHibernateImpl实现类

3> 一个UserService接口和UserServiceImpl实现类





1. 这是使用的是Maven做的项目管理工具，在使用cache（这里使用的是ehcache）之前，需要引入以下依赖

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<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.5.8</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-jdk14</artifactId>
<version>1.5.8</version>
</dependency>
<dependency>
<groupId>net.sf.ehcache</groupId>
<artifactId>ehcache</artifactId>
<version>2.2.0</version>
</dependency>
<dependency>
<groupId>org.springmodules</groupId>
<artifactId>spring-modules-cache</artifactId>
<version>0.8</version>
</dependency>




2. ehcache配置文件ehcache.xml

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<ehcache>
<defaultCache
maxElementsInMemory="500"
eternal="true"
overflowToDisk="false"
memoryStoreEvictionPolicy="LFU"/>

<cache name="userCache"
maxElementsInMemory="500"
eternal="true"
overflowToDisk="false"
memoryStoreEvictionPolicy="LFU"/>
</ehcache>






3. spring配置文件

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:ehcache="http://www.springmodules.org/schema/ehcache"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
http://www.springmodules.org/schema/ehcache http://www.springmodules.org/schema/cache/springmodules-ehcache.xsd"
default-lazy-init="true">
<ehcache:config configLocation="classpath:test/ehcache.xml" />

<ehcache:proxy id="cachedUserService" refId="userService">
<ehcache:caching methodName="find*" cacheName="userCache"/>
<ehcache:caching methodName="list*" cacheName="userCache"/>
<ehcache:flushing methodName="add*" cacheNames="userCache" when="before" />
<ehcache:flushing methodName="update*" cacheNames="userCache" when="before" />
<ehcache:flushing methodName="delete*" cacheNames="userCache" when="before" />
</ehcache:proxy>
<bean id="userService" class="test.service.UserServiceImpl">
<property name="userDao" ref="userDao"/>
</bean>

<bean id="userDao" class="test.dao.UserDaoHibernateImpl">
<property name="sessionFactory" ref="mySessionFactory"/>
</bean>
<tx:advice id="txAdvice" transaction-manager="myTransactionManager">
<tx:attributes>
<tx:method name="get*" propagation="SUPPORTS" read-only="true"/>
<tx:method name="list*" propagation="SUPPORTS" read-only="true"/>
<tx:method name="find*" propagation="SUPPORTS" read-only="true"/>
<tx:method name="*" propagation="REQUIRED" />
</tx:attributes>
</tx:advice>
<aop:config>
<aop:pointcut id="userServiceOperation" expression="execution(* *..service.UserService.*(..))"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="userServiceOperation"/>
</aop:config>
<bean id="myTransactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="mySessionFactory"/>
</bean>

<bean id="mySessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="myDataSource"/>
<property name="mappingResources">
<list>
<value>test/user.hbm.xml</value>
</list>
</property>
<property name="hibernateProperties">
<value>hibernate.dialect=org.hibernate.dialect.HSQLDialect</value>
</property>
</bean>
<bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
<property name="url" value="jdbc:hsqldb:res:hsqldb/testdb"/>
<property name="username" value="sa"/>
<property name="password" value=""/>
</bean>
</beans>




这里有几个地方需要注意：

1> 命名空间ehcache

xmlns:ehcache="http://www.springmodules.org/schema/ehcache"

http://www.springmodules.org/schema/ehcache http://www.springmodules.org/schema/cache/springmodules-ehcache.xsd

2> 以下ehcache的配置项必须放在第一行，否则会抛出异常Unexpected exception parsing XML document from class path resource [org/garbagecan/springstudy/dao/hibernate/spring-cache.xml]; nested exception is java.lang.IllegalStateException: An implementation of CacheProviderFacade should
be registered under the name 'cacheProvider'

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<ehcache:config configLocation="classpath:test/ehcache.xml" />




3> 添加了一个cachedUserService bean，直接引用真实的service bean，这里为了测试的方便，所以没有使用使用内嵌bean的定义

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<ehcache:proxy id="cachedUserService" refId="userService">
<ehcache:caching methodName="find*" cacheName="userCache"/>
<ehcache:caching methodName="list*" cacheName="userCache"/>
<ehcache:flushing methodName="add*" cacheNames="userCache" when="before" />
<ehcache:flushing methodName="update*" cacheNames="userCache" when="before" />
<ehcache:flushing methodName="delete*" cacheNames="userCache" when="before" />
</ehcache:proxy>




4. 测试Test类

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package test;
import java.util.List;
import org.garbagecan.springstudy.dao.hibernate.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {

public static void main(String[] args) throws Exception {
ApplicationContext ctx = new ClassPathXmlApplicationContext(
"/test/spring-cache.xml");
UserService userService = (UserService) ctx.getBean("userService");
UserService cachedUserService = (UserService) ctx.getBean("cachedUserService");
for (int i = 0; i < 10; i++) {
User user = new User();
user.setId("" + System.currentTimeMillis() + i);
user.setName("name_" + System.currentTimeMillis() + i);
user.setPassword("password_" + i);
cachedUserService.add(user);
}
System.out.println(cachedUserService.list());
List<User> users = userService.list();
for (User user : users) {
user.setPassword("123456");
userService.update(user);
}
System.out.println(cachedUserService.list());
for (User user : users) {
user.setPassword("123456");
cachedUserService.update(user);
}
System.out.println(cachedUserService.list());
}
}