Spring @CacheEvict Example
November 16, 2021
@CacheEvict example
1. Spring
@CacheEvict annotation is used to evict cache.
2. The
@CacheEvict is used at method level.
3. The
@Cacheable annotation sets the value in cache and on the contrary @CacheEvict evicts the cache.
4. At one method we can use
@Cacheable to cache result and at another method we can use @CacheEvict to evict cache.
5. The
@CacheEvict annotation is introduced in Spring 3.1.
The
@CacheEvict has following attributes.
1.
String[] cacheNames
2.
String[] value
cacheNames.
3.
String key
4.
String keyGenerator
KeyGenerator to use.
5.
String cacheManager
CacheManager. It is used to create default CacheResolver if none is set already.
6.
String cacheResolver
CacheResolver to use.
7.
String condition
8.
boolean allEntries
9.
boolean beforeInvocation
Using @CacheEvict
Employee.java
package com.concretepage;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
public class Employee {
@CacheEvict(value = "emp", allEntries=true)
public void setEmployee(int empId){
System.out.println("execute setEmployee method..");
}
@Cacheable("emp")
public String getEmployee(int empId){
System.out.println("execute getEmployee method..");
if(empId==1){
return "Atul";
}else{
return "Sudhir";
}
}
}
Employee class we have two methods setEmployee() and getEmployee(). We have annotated getEmployee() with @Cacheable and it will set method output in cache. The setEmployee() method is annotated with @CacheEvict and it will evict values from cache.
Find other files to run the demo application.
ehcache.xml
<?xml version="1.0" encoding="UTF-8"?> <ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://ehcache.org/ehcache.xsd"> <defaultCache eternal="true" maxElementsInMemory="100" overflowToDisk="false" /> <cache name="emp" maxElementsInMemory="10000" eternal="true" overflowToDisk="false" /> </ehcache>
<?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:context="http://www.springframework.org/schema/context"
xmlns:cache="http://www.springframework.org/schema/cache"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/cache
http://www.springframework.org/schema/cache/spring-cache.xsd">
<cache:annotation-driven />
<bean id="employee" class="com.concretepage.Employee"/>
<bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheCacheManager" p:cache-manager-ref="ehcache"/>
<bean id="ehcache" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean" p:config-location="classpath:ehcache.xml"/>
</beans>
SpringDemo.java
package com.concretepage;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class SpringDemo {
public static void main(String... args) {
AbstractApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
Employee employee=(Employee) context.getBean("employee");
//calling getEmployee method first time.
System.out.println(employee.getEmployee(1));
//calling getEmployee method second time. This time, method will not execute.
System.out.println(employee.getEmployee(1));
//calling setEmployee method to evict the cache value
employee.setEmployee(1);
//calling getEmployee method third time. This time, method will execute again.
System.out.println(employee.getEmployee(1));
}
}
getEmployee() method many times. First time getEmployee() method runs and sets result in cache named emp. Second time getEmployee() does not run because there is value in cache. Now call setEmployee() to evict the cache value. Again call getEmployee() method and this time it will run because cache value is empty. Find the output.
Output
execute getEmployee method.. Atul Atul execute setEmployee method.. execute getEmployee method.. Atul
