springboot+mybatis+ehcache实现缓存数据

一、springboot缓存简介

在 Spring Boot中，通过@EnableCaching注解自动化配置合适的缓存管理器（CacheManager），Spring Boot根据下面的顺序去侦测缓存提供者：
* Generic
* JCache (JSR-107)
* EhCache 2.x
* Hazelcast
* Infinispan
* Redis
* Guava
* Simple

关于 Spring Boot 的缓存机制：
高速缓存抽象不提供实际存储，并且依赖于由org.springframework.cache.Cache和org.springframework.cache.CacheManager接口实现的抽象。 Spring Boot根据实现自动配置合适的CacheManager，只要缓存支持通过@EnableCaching注释启用即可。

二、实例

1、application.properyies

server.port=8850

#cache 多个用逗号分开
spring.cache.cache-names=userCache
spring.cache.jcache.config=classpath:ehcache.xml

# datasource
spring.datasource.name=ehcahcetest
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3312/ehcahcetest
spring.datasource.username=root
spring.datasource.password=123456

# mybatis
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
mybatis.config-location=classpath:mybatis/mybatis-config.xml
#mybatis.type-aliases-package=

2、springboot启动类

 @SpringBootApplication
 @ComponentScan(basePackages="com.ehcache")//扫描组件
 @EnableCaching
 public class EhcacheTestApplication {

     public static void main(String[] args) {
         SpringApplication.run(EhcacheTestApplication.class, args);
     }
 }

3、加了缓存注解的service

 @Service
 public class UserService {

     @Autowired
     private UserDao userDao;

     @CacheEvict(key="'user_'+#uid", value="userCache")
     public void del(String uid) {
         // TODO Auto-generated method stub
         userDao.del(uid);
     }

     @CachePut(key="'user_'+#user.uid", value="userCache")
     public void update(User user) {
         userDao.update(user);
     }

     @Cacheable(key="'user_'+#uid",value="userCache")
     public User getUserById(String uid){
         System.err.println("缓存里没有"+uid+",所以这边没有走缓存，从数据库拿数据");
         return userDao.findById(uid);

     }

     @CacheEvict(key="'user'",value="userCache")
     public String save(User user) {
         // TODO Auto-generated method stub
         return userDao.save(user);
     }

 }

4、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">
     <diskStore path="java.io.tmpdir" />

     <!-- 配置提供者 1、peerDiscovery，提供者方式，有两种方式：自动发现(automatic)、手动配置(manual) 2、rmiUrls，手动方式时提供者的地址，多个的话用|隔开 -->
     <cacheManagerPeerProviderFactory
         class="net.sf.ehcache.distribution.RMICacheManagerPeerProviderFactory"
         properties="peerDiscovery=manual,rmiUrls=//127.0.0.1:40002/userCache" />
     <!-- <cacheManagerPeerProviderFactory
         class="net.sf.ehcache.distribution.RMICacheManagerPeerProviderFactory"
         properties="peerDiscovery=automatic, multicastGroupAddress=230.0.0.1, multicastGroupPort=4446,timeToLive=255"/>
  -->
     <!-- 配置监听器 1、hostName 主机地址 2、port 端口 3、socketTimeoutMillis socket子模块的超时时间，默认是2000ms -->
     <cacheManagerPeerListenerFactory
         class="net.sf.ehcache.distribution.RMICacheManagerPeerListenerFactory"
         properties="hostName=127.0.0.1, port=40001, socketTimeoutMillis=2000" />
     <!-- <cacheManagerPeerListenerFactory
          class="net.sf.ehcache.distribution.RMICacheManagerPeerListenerFactory"/> -->

     <defaultCache eternal="false" maxElementsInMemory="1000"
         overflowToDisk="false" diskPersistent="false" timeToIdleSeconds="0"
         timeToLiveSeconds="600" memoryStoreEvictionPolicy="LRU" />

     <cache
         name="userCache"
         maxElementsInMemory="1000"
         eternal="false"
         timeToIdleSeconds="300"
         timeToLiveSeconds="300"
         overflowToDisk="false"
         memoryStoreEvictionPolicy="LRU">

         <!-- 配置缓存事件监听器 replicateAsynchronously 操作是否异步,默认值为true. replicatePuts 添加操作是否同步到集群内的其他缓存,默认为true.
             replicateUpdates 更新操作是否同步到集群内的其他缓存,默认为true. replicateUpdatesViaCopy 更新之后的对象是否复制到集群中的其他缓存(true);
             replicateRemovals 删除操作是否同步到集群内的其他缓存,默认为true. -->
         <cacheEventListenerFactory
             class="net.sf.ehcache.distribution.RMICacheReplicatorFactory"
             properties="
                     replicateAsynchronously=true,
                     replicatePuts=true,
                     replicateUpdates=true,
                     replicateUpdatesViaCopy=true,
                     replicateRemovals=true " />

          <!-- 初始化缓存，以及自动设置 -->
         <bootstrapCacheLoaderFactory
             class="net.sf.ehcache.distribution.RMIBootstrapCacheLoaderFactory"
             properties="bootstrapAsynchronously=true" />

     </cache>

 </ehcache>

5、OperationController.java 测试类

 package com.ehcache.controller;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 import javax.servlet.http.HttpServletRequest;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.cache.annotation.CachePut;
 import org.springframework.cache.annotation.Cacheable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.RestController;

 import com.ehcache.entity.User;
 import com.ehcache.factory.CacheManagerFactory;
 import com.ehcache.factory.UserFactory;
 import com.ehcache.service.UserService;
 import com.google.gson.Gson;

 import net.sf.ehcache.Element;

 @RestController
 @RequestMapping("/o")
 public class OperationController {

     @Autowired
     private UserService userService;

     Gson gson = new Gson();

     CacheManagerFactory cmf = CacheManagerFactory.getInstance();

     @RequestMapping(value = "/test", method = RequestMethod.GET)
     public String test(HttpServletRequest request){

         // 保存一个新用户
         String uid = userService.save(UserFactory.createUser());
         User user = userService.getUserById(uid);
         user.setUsername("xiaoli");
         userService.update(user);

         // 查询该用户
         System.out.println(gson.toJson(user, User.class));
         /*System.out.println();
         // 再查询该用户
         User user = userService.getUserById(uid);
         System.out.println(gson.toJson(user, User.class));
         System.out.println();
         // 更新该用户
         userService.update(user);
         // 更新好了再查询该用户
         System.out.println(gson.toJson(userService.getUserById(uid), User.class));
         System.out.println();
         // 删除该用户
         userService.del(uid);
         System.out.println();
         // 删除好了再查询该用户
         System.out.println(gson.toJson(userService.getUserById(uid), User.class));*/

         // 再保存一个新用户
 //        String uid1 = userService.save(UserFactory.createUser());

         return uid;
     }

     @RequestMapping(value = "/test1", method = RequestMethod.GET)
     public String test1(HttpServletRequest request,String key){

         String res = "";

         Element element = cmf.getElement("userCache", "map");
         if(element == null){
             Map<String, String> map = new HashMap<String, String>();
             map.put(key, key);
             cmf.setElement("userCache", new Element("map", map));
         }else{
             Map<String, String> map = (Map<String, String>) element.getValue();
             res = map.get(key);
             if(res == null){
                 map.put(key, key);
                 // 多次测试发现，存在同名Element是，重复put的是无法复制的，因此当遇到两个节点同步不上的时候，先remove后put。
                 cmf.getCache("userCache").remove("map");
                 cmf.setElement("userCache", new Element("map", map));
                 res = "0;null";
             }
         }
         return res;
     }

 }