@SpringBootApplication
@EnableCaching  //开启缓存
public class DemoApplication{

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

}　

@Override
@Cacheable("menu")
public Menu findById(String id) {
    Menu menu = this.getById(id);
    if (menu != null){
        System.out.println("menu.name = " + menu.getName());
    }
    return menu;
}

@Override
    @Cacheable({"menu", "menuById"})
    public Menu findById(String id) {
        Menu menu = this.getById(id);
        if (menu != null){
            System.out.println("menu.name = " + menu.getName());
        }
        return menu;
    }
 
---------
@GetMapping("/findById/{id}")
public Menu findById(@PathVariable("id")String id){
    Menu menu0 = menuService.findById("fe278df654adf23cf6687f64d1549c0a");
    Menu menu2 = menuService.findById("fb6106721f289ebf0969565fa8361c75");
    return menu0;
}

    @CachePut(value = "newJob", key = "#p0")  //按条件更新缓存
    public NewJob updata(NewJob job) {
        NewJob newJob = newJobDao.findAllById(job.getId());
        newJob.updata(job);
        return job;
    }

    @Cacheable(value = "emp",key = "#p0.id")
    public NewJob save(NewJob job) {
        newJobDao.save(job);
        return job;
    }

    //清除一条缓存，key为要清空的数据
    @CacheEvict(value="emp",key="#id")
    public void delect(int id) {
        newJobDao.deleteAllById(id);
    }

    //方法调用后清空所有缓存
    @CacheEvict(value="accountCache",allEntries=true)
    public void delectAll() {
        newJobDao.deleteAll();
    }

    //方法调用前清空所有缓存
    @CacheEvict(value="accountCache",beforeInvocation=true)
    public void delectAll() {
        newJobDao.deleteAll();
    }

@CacheConfig(cacheNames = {"myCache"})
public class BotRelationServiceImpl implements BotRelationService {
    @Override
    @Cacheable(key = "targetClass + methodName +#p0")//此处没写value
    public List<BotRelation> findAllLimit(int num) {
        return botRelationRepository.findAllLimit(num);
    }
    .....
}

//注册1个id为cacheManager,类型为ConcurrentMapCacheManager的bean
@Bean
public ConcurrentMapCacheManager cacheManager() {
    ConcurrentMapCacheManager cacheManager = new ConcurrentMapCacheManager(); //实例化ConcurrentMapCacheManager
    List<String> cacheNames = this.cacheProperties.getCacheNames(); //读取配置文件，如果配置有spring.cache.cache-names=xx,xx,则进行配置cacheNames,默认是没有配置的
    if (!cacheNames.isEmpty()) {
        cacheManager.setCacheNames(cacheNames);
    }
    return this.customizerInvoker.customize(cacheManager); //调用CacheManagerCustomizers#customize 进行个性化设置,在该方法中是遍历其持有的List
}

@SpringBootApplication
@EnableCaching// 开启缓存，需要显示的指定
public class SpringBootStudentCacheCaffeineApplication {
 
    public static void main(String[] args) {
        SpringApplication.run(SpringBootStudentCacheCaffeineApplication.class, args);
    }
}

/**
 * 必须要指定这个Bean，refreshAfterWrite=5s这个配置属性才生效
 *
 * @return
 */
@Bean
public CacheLoader<Object, Object> cacheLoader() {
 
    CacheLoader<Object, Object> cacheLoader = new CacheLoader<Object, Object>() {
 
        @Override
        public Object load(Object key) throws Exception {
            return null;
        }
 
        // 重写这个方法将oldValue值返回回去，进而刷新缓存
        @Override
        public Object reload(Object key, Object oldValue) throws Exception {
            return oldValue;
        }
    };
 
    return cacheLoader;
}

import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.concurrent.TimeUnit;

@Configuration
public class CacheConfig {

    @Bean
    public Cache caffeineCache() {
        return Caffeine.newBuilder()
                // 设置最后一次写入或访问后经过固定时间过期
                .expireAfterWrite(60, TimeUnit.SECONDS)
                // 初始的缓存空间大小
                .initialCapacity(100)
                // 缓存的最大条数
                .maximumSize(1000)
                .build();
    }

}

@Slf4j
@Service
public class UserInfoServiceImpl implements UserInfoService {

    /**
     * 模拟数据库存储数据
     */
    private HashMap userInfoMap = new HashMap<>();

    @Autowired
    Cache<String, Object> caffeineCache;

    @Override
    public void addUserInfo(UserInfo userInfo) {
        log.info("create");
        userInfoMap.put(userInfo.getId(), userInfo);
        // 加入缓存
        caffeineCache.put(String.valueOf(userInfo.getId()),userInfo);
    }

    @Override
    public UserInfo getByName(Integer id) {
        // 先从缓存读取
        caffeineCache.getIfPresent(id);
        UserInfo userInfo = (UserInfo) caffeineCache.asMap().get(String.valueOf(id));
        if (userInfo != null){
            return userInfo;
        }
        // 如果缓存中不存在，则从库中查找
        log.info("get");
        userInfo = userInfoMap.get(id);
        // 如果用户信息不为空，则加入缓存
        if (userInfo != null){
            caffeineCache.put(String.valueOf(userInfo.getId()),userInfo);
        }
        return userInfo;
    }

    @Override
    public UserInfo updateUserInfo(UserInfo userInfo) {
        log.info("update");
        if (!userInfoMap.containsKey(userInfo.getId())) {
            return null;
        }
        // 取旧的值
        UserInfo oldUserInfo = userInfoMap.get(userInfo.getId());
        // 替换内容
        if (!StringUtils.isEmpty(oldUserInfo.getAge())) {
            oldUserInfo.setAge(userInfo.getAge());
        }
        if (!StringUtils.isEmpty(oldUserInfo.getName())) {
            oldUserInfo.setName(userInfo.getName());
        }
        if (!StringUtils.isEmpty(oldUserInfo.getSex())) {
            oldUserInfo.setSex(userInfo.getSex());
        }
        // 将新的对象存储，更新旧对象信息
        userInfoMap.put(oldUserInfo.getId(), oldUserInfo);
        // 替换缓存中的值
        caffeineCache.put(String.valueOf(oldUserInfo.getId()),oldUserInfo);
        return oldUserInfo;
    }

    @Override
    public void deleteById(Integer id) {
        log.info("delete");
        userInfoMap.remove(id);
        // 从缓存中删除
        caffeineCache.asMap().remove(String.valueOf(id));
    }

}

@Configuration
public class CacheConfig {

    /**
     * 配置缓存管理器
     *
     * @return 缓存管理器
     */
    @Bean("caffeineCacheManager")
    public CacheManager cacheManager() {
        CaffeineCacheManager cacheManager = new CaffeineCacheManager();
        cacheManager.setCaffeine(Caffeine.newBuilder()
                // 设置最后一次写入或访问后经过固定时间过期
                .expireAfterAccess(60, TimeUnit.SECONDS)
                // 初始的缓存空间大小
                .initialCapacity(100)
                // 缓存的最大条数
                .maximumSize(1000));
        return cacheManager;
    }

}

@Slf4j
@Service
@CacheConfig(cacheNames = "caffeineCacheManager")
public class UserInfoServiceImpl implements UserInfoService {

    /**
     * 模拟数据库存储数据
     */
    private HashMap userInfoMap = new HashMap<>();

    @Override
    @CachePut(key = "#userInfo.id")
    public void addUserInfo(UserInfo userInfo) {
        log.info("create");
        userInfoMap.put(userInfo.getId(), userInfo);
    }

    @Override
    @Cacheable(key = "#id")
    public UserInfo getByName(Integer id) {
        log.info("get");
        return userInfoMap.get(id);
    }

    @Override
    @CachePut(key = "#userInfo.id")
    public UserInfo updateUserInfo(UserInfo userInfo) {
        log.info("update");
        if (!userInfoMap.containsKey(userInfo.getId())) {
            return null;
        }
        // 取旧的值
        UserInfo oldUserInfo = userInfoMap.get(userInfo.getId());
        // 替换内容
        if (!StringUtils.isEmpty(oldUserInfo.getAge())) {
            oldUserInfo.setAge(userInfo.getAge());
        }
        if (!StringUtils.isEmpty(oldUserInfo.getName())) {
            oldUserInfo.setName(userInfo.getName());
        }
        if (!StringUtils.isEmpty(oldUserInfo.getSex())) {
            oldUserInfo.setSex(userInfo.getSex());
        }
        // 将新的对象存储，更新旧对象信息
        userInfoMap.put(oldUserInfo.getId(), oldUserInfo);
        // 返回新对象信息
        return oldUserInfo;
    }

    @Override
    @CacheEvict(key = "#id")
    public void deleteById(Integer id) {
        log.info("delete");
        userInfoMap.remove(id);
    }

} 

@Configuration  
@EnableCaching
public class CacheConfig {  
  
    @Bean  
    public CacheManager cacheManager() {  
        return new EhCacheCacheManager(ehCacheCacheManager().getObject());  
    }  
  
    @Bean  
    public EhCacheManagerFactoryBean ehCacheCacheManager() {  
        EhCacheManagerFactoryBean cmfb = new EhCacheManagerFactoryBean();  
        cmfb.setConfigLocation(new ClassPathResource("ehcache.xml"));  
        cmfb.setShared(true);  
        return cmfb;  
    }  
  
}

@Bean
public RedisTemplate<String, Object> redisTemplate(LettuceConnectionFactory connectionFactory) {
    // 配置redisTemplate
    RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
    redisTemplate.setConnectionFactory(connectionFactory);
    redisTemplate.setKeySerializer(new StringRedisSerializer());//key序列化
    redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());//value序列化
    redisTemplate.afterPropertiesSet();
    return redisTemplate;
}

 /**
     * 通过RedisCacheManager配置过期时间
     *
     * @param redisConnectionFactory
     * @return
     */
    @Bean
    public RedisCacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
        RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofHours(1)); // 设置缓存有效期一小时
        return RedisCacheManager
                .builder(RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory))
                .cacheDefaults(redisCacheConfiguration).build();
    }

/**
 * 自定义缓存配置文件，继承 CachingConfigurerSupport
 * Created by huanl on 2017/8/22.
 */
@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport{
    public RedisConfig() {
        super();
    }

    /**
     * 指定使用哪一种缓存
     * @param redisTemplate
     * @return
     */
    @Bean
    public CacheManager cacheManager(RedisTemplate<?,?> redisTemplate) {
        RedisCacheManager rcm = new RedisCacheManager(redisTemplate);
        return rcm;
    }

    /**
     * 指定默认的key生成方式
     * @return
     */
    @Override
    public KeyGenerator keyGenerator() {
       KeyGenerator keyGenerator = new KeyGenerator() {
           @Override
           public Object generate(Object o, Method method, Object... objects) {
               StringBuilder sb = new StringBuilder();
               sb.append(o.getClass().getName());
               sb.append(method.getName());
               for (Object obj : objects) {
                   sb.append(obj.toString());
               }
               return sb.toString();
           }
       };
       return keyGenerator;
    }

    @Override
    public CacheResolver cacheResolver() {
        return super.cacheResolver();
    }

    @Override
    public CacheErrorHandler errorHandler() {
        return super.errorHandler();
    }

    /**
     * redis 序列化策略 ，通常情况下key值采用String序列化策略
     * StringRedisTemplate默认采用的是String的序列化策略，保存的key和value都是采用此策略序列化保存的。StringRedisSerializer
     * RedisTemplate默认采用的是JDK的序列化策略，保存的key和value都是采用此策略序列化保存的。JdkSerializationRedisSerializer
     * @param factory
     * @return
     */
    @Bean
    public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory factory){
        RedisTemplate<Object, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(factory);

//        // 使用Jackson2JsonRedisSerialize 替换默认序列化
//        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
//        ObjectMapper om = new ObjectMapper();
//        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
//        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
//        jackson2JsonRedisSerializer.setObjectMapper(om);
//
//
//        //设置value的序列化方式
//        redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
//        //设置key的序列化方式
//        redisTemplate.setKeySerializer(new StringRedisSerializer());
//        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
//        redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);

        //使用fastJson作为默认的序列化方式
        GenericFastJsonRedisSerializer genericFastJsonRedisSerializer = new GenericFastJsonRedisSerializer();
        redisTemplate.setDefaultSerializer(genericFastJsonRedisSerializer);
        redisTemplate.setValueSerializer(genericFastJsonRedisSerializer);
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(genericFastJsonRedisSerializer);
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.afterPropertiesSet();

        return redisTemplate;

    }

    /**
     * 转换返回的object为json
     * @return
     */
    @Bean
    public HttpMessageConverters fastJsonHttpMessageConverters(){
        // 1、需要先定义一个converter 转换器
        FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
        // 2、添加fastJson 的配置信息，比如：是否要格式化返回的json数据
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
        // 3、在convert 中添加配置信息
        fastConverter.setFastJsonConfig(fastJsonConfig);
        // 4、将convert 添加到converters当中
        HttpMessageConverter<?> converter = fastConverter;
        return new HttpMessageConverters(converter);
    }


}

@Autowired
private StringRedisTemplate stringRedisTemplate;//操作key-value都是字符串

@Autowired
private RedisTemplate redisTemplate;//操作key-value都是对象

@Autowired
private RedisCacheManager redisCacheManager;
/**
 *  Redis常见的五大数据类型：
 *  stringRedisTemplate.opsForValue();[String(字符串)]
 *  stringRedisTemplate.opsForList();[List(列表)]
 *  stringRedisTemplate.opsForSet();[Set(集合)]
 *  stringRedisTemplate.opsForHash();[Hash(散列)]
 *  stringRedisTemplate.opsForZSet();[ZSet(有序集合)]
 */
public void test(){
    stringRedisTemplate.opsForValue().append("msg","hello");
    Cache emp = redisCacheManager.getCache("emp");
    emp.put("111", "222");
}