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;
    }
    
    
}