2020-12-18

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-cache</artifactId>

<version>${boot.version}</version>

</dependency>

spring:

      #cache:

        #缓存名称

        #cache-names: guavaDemo

        #缓存最大数量500条, 缓存失效时间 6个小时

        #guava.spec: maximumSize=500,expireAfterWrite=360m

      # REDIS (RedisProperties)  

      redis :

        host : localhost # server host  

        port : 6379 # connection port  

        password : 123

        pool.max-idle : 8 # pool settings ...  

        pool.min-idle : 1

        pool.max-active : 8  

        pool.max-wait : -1  

package com.ding.data.config;


import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.concurrent.TimeUnit;


import javax.annotation.Resource;


import org.springframework.boot.ApplicationArguments;

import org.springframework.boot.ApplicationRunner;

import org.springframework.cache.CacheManager;

import org.springframework.cache.guava.GuavaCacheManager;

import org.springframework.cache.support.CompositeCacheManager;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.Primary;

import org.springframework.data.redis.cache.RedisCacheManager;

import org.springframework.data.redis.core.RedisTemplate;

import org.springframework.data.redis.serializer.StringRedisSerializer;


import com.google.common.cache.CacheBuilder;

import com.google.common.collect.Lists;


@Configuration

public class CacheConfig implements ApplicationRunner {

@Resource

private List<CacheManager> cacheManagers;


public void run(ApplicationArguments args) throws Exception {

System.out.println("CacheManager大小为=========" + cacheManagers.size());

System.out.println("=================================================");

for(CacheManager c:cacheManagers){

System.out.println(c.getCacheNames());

}

}


@Bean(name = "redisCacheManager")

public RedisCacheManager redisCacheManager(

RedisTemplate<Object, Object> redisTemplate) {

redisTemplate.setKeySerializer(new StringRedisSerializer());

RedisCacheManager redisCacheManager = new RedisCacheManager(

redisTemplate);

redisCacheManager.setCacheNames(Arrays.asList("redisDemo"));

redisCacheManager.setUsePrefix(true);

return redisCacheManager;

}


@Bean(name = "guavaCacheManager")

public GuavaCacheManager getGuavaCacheManager() {

GuavaCacheManager guavaCacheManager = new GuavaCacheManager();

guavaCacheManager.setCacheBuilder(CacheBuilder.newBuilder()

.expireAfterWrite(3600, TimeUnit.SECONDS).maximumSize(1000));

ArrayList<String> guavaCacheNames = Lists.newArrayList();

guavaCacheNames.add("guavaDemo");

guavaCacheManager.setCacheNames(guavaCacheNames);

return guavaCacheManager;

}


@Bean(name = "cacheManager")

@Primary

public CompositeCacheManager cacheManager(

RedisCacheManager redisCacheManager,

GuavaCacheManager guavaCacheManager) {

CompositeCacheManager cacheManager = new CompositeCacheManager(

redisCacheManager, guavaCacheManager);

return cacheManager;

}

}

要点4--guava缓存

package com.ding.data.cache;


import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.HashMap;

import java.util.Map;


import javax.annotation.PostConstruct;


import org.springframework.cache.annotation.CacheEvict;

import org.springframework.cache.annotation.CachePut;

import org.springframework.cache.annotation.Cacheable;

import org.springframework.stereotype.Service;


@Service

//@CacheConfig(cacheManager = "guavaCacheManager")

public class GuavaDataCache {


private Map<Long, String> dataMap = new HashMap<Long, String>();


/**

 * 初始化

 */

@PostConstruct

public void init() {

dataMap.put(1L, "张三");

dataMap.put(2L, "李四");

dataMap.put(3L, "王五");

}


/**

 * 查询

 * 如果数据没有缓存,那么从dataMap里面获取,如果缓存了,

 * 那么从guavaDemo里面获取

 * 并且将缓存的数据存入到 guavaDemo里面

 * 其中key 为 #id+dataMap

 */

@Cacheable(value="guavaDemo" ,key="#id + 'dataMap'")

public String query(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

System.out.println(sdf.format(new Date()) + " : query id is " + id);

return dataMap.get(id);

}


/**

 * 插入 或者更新

 * 插入或更新数据到dataMap中

 * 并且缓存到 guavaDemo中

 * 如果存在了那么更新缓存中的值

 * 其中key 为 #id+dataMap

 */

@CachePut(value="guavaDemo" ,key="#id + 'dataMap'")

public String put(Long id, String value) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

System.out.println(sdf.format(new Date()) + " : add data ,id is "+ id);

dataMap.put(id, value);

// data persistence

return value;

}


/**

 * 删除

 * 删除dataMap里面的数据

 * 并且删除缓存guavaDemo中的数据

 * 其中key 为 #id+dataMap

 */

@CacheEvict(value="guavaDemo" , key="#id + 'dataMap'")

public void remove(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

System.out.println(sdf.format(new Date()) + " : remove id is "+ id + " data");

dataMap.remove(id);

// data remove  

}


}

要点5--redis缓存

package com.ding.data.cache;


import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.HashMap;

import java.util.Map;


import javax.annotation.PostConstruct;


import org.springframework.cache.annotation.CacheEvict;

import org.springframework.cache.annotation.CachePut;

import org.springframework.cache.annotation.Cacheable;

import org.springframework.stereotype.Service;


@Service

//@CacheConfig(cacheManager = "redisCacheManager")

public class RedisDataCache {


private Map<Long, String> dataMap = new HashMap<Long, String>();


/**

 * 初始化

 */

@PostConstruct

public void init() {

dataMap.put(1L, "111");

dataMap.put(2L, "222");

dataMap.put(3L, "333");

}


/**

 * 查询

 * 如果数据没有缓存,那么从dataMap里面获取,如果缓存了,

 * 那么从guavaDemo里面获取

 * 并且将缓存的数据存入到 guavaDemo里面

 * 其中key 为 #id+dataMap

 */

@Cacheable(value="redisDemo" ,key="#id + 'dataMap'")

public String query(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

System.out.println(sdf.format(new Date()) + " : query id is " + id);

return dataMap.get(id);

}


/**

 * 插入 或者更新

 * 插入或更新数据到dataMap中

 * 并且缓存到 guavaDemo中

 * 如果存在了那么更新缓存中的值

 * 其中key 为 #id+dataMap

 */

@CachePut(value="redisDemo" ,key="#id + 'dataMap'")

public String put(Long id, String value) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

System.out.println(sdf.format(new Date()) + " : add data ,id is "+ id);

dataMap.put(id, value);

// data persistence

return value;

}


/**

 * 删除

 * 删除dataMap里面的数据

 * 并且删除缓存guavaDemo中的数据

 * 其中key 为 #id+dataMap

 */

@CacheEvict(value="redisDemo" , key="#id + 'dataMap'")

public void remove(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

System.out.println(sdf.format(new Date()) + " : remove id is "+ id + " data");

dataMap.remove(id);

// data remove  

}


}

要点6--调用

package com.ding.data;


import java.text.SimpleDateFormat;

import java.util.Date;


import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cache.annotation.EnableCaching;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;


import com.ding.data.cache.GuavaDataCache;

import com.ding.data.cache.RedisDataCache;


/**

 * 是Spring Boot项目的核心注解,主要是开启自动配置

 */

@SpringBootApplication

// same as @Configuration @EnableAutoConfiguration @ComponentScan

@RestController

// 开启缓存

@EnableCaching

public class App {


@Autowired

private GuavaDataCache dataCache;


@Autowired

private RedisDataCache rdataCache;


public static void main(String[] args) {

SpringApplication.run(App.class, args);

}


@RequestMapping("/put")

public String put(Long id, String value) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

return sdf.format(new Date()) + " : value is "

+ dataCache.put(id, value);

}


@RequestMapping("/get")

public String query(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

return sdf.format(new Date()) + " : value is " + dataCache.query(id);

}


@RequestMapping("/remove")

public String remove(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

dataCache.remove(id);

return sdf.format(new Date()) + " : success ";

}


@RequestMapping("/putr")

public String putr(Long id, String value) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

return sdf.format(new Date()) + " : value is "

+ rdataCache.put(id, value);

}


@RequestMapping("/getr")

public String queryr(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

return sdf.format(new Date()) + " : value is " + rdataCache.query(id);

}


@RequestMapping("/remover")

public String remover(Long id) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

rdataCache.remove(id);

return sdf.format(new Date()) + " : success ";

}


}

测试1--redis中是否有写入--有的

RedisCache访问

访问

http://localhost:8080/getr?id=1

查看Redis服务器中，如下

可见

/getr?id=1

这个链接返回时将数据写入了Redis服务器中。

测试2--guava缓存的访问

访问

http://localhost:8080/get?id=1

然后调用

http://localhost:8080/put?id=1&value=777777

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查看Redis中的值，并未发生任何改变。说明redis缓存和guava缓存互不干扰，都按照设想的进行了正确的访问。为什么这么说？因为之前试过别的配置，结果发现缓存发生了混乱，而现在正常，说明现在的配置类文件和相关的配置信息都写正确了。

★要点3讲解

项目启动过程中打印

项目启动过程中打印如下。ApplicationRunner接口的具体用法可以自行百度。实现ApplicationRunner接口并不是必须的，这里就是为了启动时打印展示CacheManager。

从图中可以看到被 @Bean 注解的三个CachaManager都加进了 cacheManagers 中。

CompositeCacheManager

Spring Cache在 CacheManager 之下可以采用缓存名称(cacheNames 属性)来对缓存进行区分。Spring Cache 提供了CompositeCacheManager 来对所有的 CacheManager 进行代理。根据指定的cacheName 去遍历所有的 CacheManager，查找对应的缓存。