SpringBoot --- 缓存Cache/Redis

整理不易，不喜勿喷。谢谢

SpringBoot — 整合Ldap.
SpringBoot — 整合Spring Data JPA.
SpringBoot — 整合Elasticsearch.
SpringBoot — 整合spring-data-jpa和spring-data-elasticsearch.
SpringBoot — 整合thymeleaf.
SpringBoot — 注入第三方jar包.
SpringBoot — 整合Redis.
Springboot — 整合slf4j打印日志.
Springboot — 整合定时任务，自动执行方法.
Springboot — 配置多数据源,使用JdbcTemplate以及NamedParameterJdbcTemplate.
Sprignboot — 详解pom.xml中build和profile.
SpringBoot — 监控.
SpringBoot — 缓存Cache/Redis.
SpringBoot与Zookeeper.
Git的使用.

有时间多研究一下这个包，spring-boot-autoconfigure

1.依赖

        
        
            org.springframework.boot
            spring-boot-starter-cache
        
        
        
            org.springframework.boot
            spring-boot-starter-data-redis
        

2.application.properties

spring.cache.type= ＃缓存的技术类型，可选 generic,ehcache,hazelcast,infinispan,jcache,redis,guava,simple,none
spring.cache.cache-names=user,menu
spring.cache.redis.time-to-live=600000
spring.cache.redis.key-prefix=com.cache

spring.redis.host=127.0.0.1
spring.redis.port=6379
spring.redis.password=Redis!123
spring.redis.jedis.pool.max-active=8
spring.redis.jedis.pool.max-wait=-1ms
spring.redis.jedis.pool.max-idle=500
spring.redis.jedis.pool.min-idle=0
spring.redis.lettuce.shutdown-timeout=0ms

选项	作用
Simple	基于ConcurrentHashMap实现的缓存，适合单体或者开发环境
none	关闭缓存，
redis	使用Redis作为缓存，
Generic	用户自定义缓存实现，实现org.springframework.cache.CacheManager

3.注解

@Cacheable

• value、cacheNames：两个等同的参数（cacheNames为Spring 4新增，作为value的别名），用于指定缓存存储的集合名。由于Spring 4中新增了@CacheConfig，因此在Spring 3中原本必须有的value属性，也成为非必需项了
• key：缓存对象存储在Map集合中的key值，非必需，缺省按照函数的所有参数组合作为key值，若自己配置需使用SpEL表达式，比如：@Cacheable(key = “#p0”)：使用函数第一个参数作为缓存的key值
• condition：缓存对象的条件，非必需，也需使用SpEL表达式，只有满足表达式条件的内容才会被缓存，比如：@Cacheable(key = “#p0”, condition = “#p0.length() < 3”)，表示只有当第一个参数的长度小于3的时候才会被缓存
• unless：另外一个缓存条件参数，非必需，需使用SpEL表达式。它不同于condition参数的地方在于它的判断时机，该条件是在函数被调用之后才做判断的，所以它可以通过对result进行判断。
• keyGenerator：用于指定key生成器，非必需。若需要指定一个自定义的key生成器，我们需要去实现org.springframework.cache.interceptor.KeyGenerator接口，并使用该参数来指定。需要注意的是：该参数与key是互斥的
• cacheManager：用于指定使用哪个缓存管理器，非必需。只有当有多个时才需要使用
• cacheResolver：用于指定使用那个缓存解析器，非必需。需通过org.springframework.cache.interceptor.CacheResolver接口来实现自己的缓存解析器，并用该参数指定

public class BookServiceImpl implements BookService {
　　@Cacheable("books")
    public Book findBook(ISBN isbn) {...}
    
    @Cacheable({"books", "users"})
    public Book findBook(ISBN isbn) {...} 

    @Cacheable(cacheNames="books", key="#isbn")
    public Book findBook(ISBN isbn, boolean checkWarehouse, boolean includeUsed)
    
    @Cacheable(cacheNames="books", key="#isbn.rawNumber")
    public Book findBook(ISBN isbn, boolean checkWarehouse, boolean includeUsed)
    
    @Cacheable(cacheNames="books", key="T(someType).hash(#isbn)")
    public Book findBook(ISBN isbn, boolean checkWarehouse, boolean includeUsed)

    @Cacheable(cacheNames="book", condition="#name.length() < 32") 
    public Book findBook(String name)
    
    @Cacheable(cacheNames="book", condition="#name.length() < 32", unless="#result.hardback") 
    public Book findBook(String name) 
    .....
}

@CachePut

• 主要针对方法配置，能够根据方法的请求参数对其结果进行缓存，和 @Cacheable 不同的是，它每次都会触发真实方法的调用 。简单来说就是用户更新缓存数据。但需要注意的是该注解的value 和 key 必须与要更新的缓存相同，也就是与@Cacheable 相同。

public class BookServiceImpl implements BookService {
    @CachePut(cacheNames="book", key="#isbn")
    public Book updateBook(ISBN isbn, BookDescriptor descriptor)
}

@CacheEvict配置于函数上，通常用在删除方法上，用来从缓存中移除相应数据。

• allEntries：非必需，默认为false。当为true时，会移除所有数据。如：@CachEvict(value=”testcache”,allEntries=true)
• beforeInvocation：非必需，默认为false，会在调用方法之后移除数据。当为true时，会在调用方法之前移除数据。 如：@CachEvict(value=”testcache”，beforeInvocation=true)

public class BookServiceImpl implements BookService {
    @CacheEvict(cacheNames="books") 
    public void loadBooks(InputStream batch)
    
    //对cacheNames进行批量删除
    @CacheEvict(cacheNames="books", allEntries=true) 
    public void loadBooks(InputStream batch) 
}

@Caching 可以混合各种注解

public class BookServiceImpl implements BookService {
    @Caching(evict = { @CacheEvict("primary"), @CacheEvict(cacheNames="secondary", key="#p0") })
    public Book importBooks(String deposit, Date date) 
}

@CacheConfig统一配置本类的缓存注解的属性，在类上面统一定义缓存的名字，方法上面就不用标注了，当标记在一个类上时则表示该类所有的方法都是支持缓存的

@CacheConfig("books")
public class BookServiceImpl implements BookService {
        @Cacheable
        public Book findBook(ISBN isbn) {...}
    }  
}

4.代码

1.开启缓存

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

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

2.查看源码

package org.springframework.boot.autoconfigure.cache;

import java.util.LinkedHashSet;
import java.util.List;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.cache.CacheProperties.Redis;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration;
import org.springframework.cache.CacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ResourceLoader;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheManager.RedisCacheManagerBuilder;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext.SerializationPair;

/**
 * Redis cache configuration.
 *
 * @author Stephane Nicoll
 * @author Mark Paluch
 * @author Ryon Day
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(RedisConnectionFactory.class)
@AutoConfigureAfter(RedisAutoConfiguration.class)
@ConditionalOnBean(RedisConnectionFactory.class)
@ConditionalOnMissingBean(CacheManager.class)
@Conditional(CacheCondition.class)
class RedisCacheConfiguration {

	@Bean
	RedisCacheManager cacheManager(CacheProperties cacheProperties, CacheManagerCustomizers cacheManagerCustomizers,
			ObjectProvider<org.springframework.data.redis.cache.RedisCacheConfiguration> redisCacheConfiguration,
			ObjectProvider<RedisCacheManagerBuilderCustomizer> redisCacheManagerBuilderCustomizers,
			RedisConnectionFactory redisConnectionFactory, ResourceLoader resourceLoader) {
		RedisCacheManagerBuilder builder = RedisCacheManager.builder(redisConnectionFactory).cacheDefaults(
				determineConfiguration(cacheProperties, redisCacheConfiguration, resourceLoader.getClassLoader()));
		List<String> cacheNames = cacheProperties.getCacheNames();
		if (!cacheNames.isEmpty()) {
			builder.initialCacheNames(new LinkedHashSet<>(cacheNames));
		}
		if (cacheProperties.getRedis().isEnableStatistics()) {
			builder.enableStatistics();
		}
		redisCacheManagerBuilderCustomizers.orderedStream().forEach((customizer) -> customizer.customize(builder));
		return cacheManagerCustomizers.customize(builder.build());
	}

	private org.springframework.data.redis.cache.RedisCacheConfiguration determineConfiguration(
			CacheProperties cacheProperties,
			ObjectProvider<org.springframework.data.redis.cache.RedisCacheConfiguration> redisCacheConfiguration,
			ClassLoader classLoader) {
		return redisCacheConfiguration.getIfAvailable(() -> createConfiguration(cacheProperties, classLoader));
	}

	private org.springframework.data.redis.cache.RedisCacheConfiguration createConfiguration(
			CacheProperties cacheProperties, ClassLoader classLoader) {
		Redis redisProperties = cacheProperties.getRedis();
		org.springframework.data.redis.cache.RedisCacheConfiguration config = org.springframework.data.redis.cache.RedisCacheConfiguration
				.defaultCacheConfig();
		config = config.serializeValuesWith(
				SerializationPair.fromSerializer(new JdkSerializationRedisSerializer(classLoader)));
		if (redisProperties.getTimeToLive() != null) {
			config = config.entryTtl(redisProperties.getTimeToLive());
		}
		if (redisProperties.getKeyPrefix() != null) {
			config = config.prefixCacheNameWith(redisProperties.getKeyPrefix());
		}
		if (!redisProperties.isCacheNullValues()) {
			config = config.disableCachingNullValues();
		}
		if (!redisProperties.isUseKeyPrefix()) {
			config = config.disableKeyPrefix();
		}
		return config;
	}

}