今天我们来讲讲怎么在spring boot 中整合redis 实现对数据库查询结果的缓存。
首先第一步要做的就是在pom.xml文件添加spring-boot-starter-data-redis。
要整合缓存，必不可少的就是我们要继承一个父类CachingConfigurerSupport。我们先看看这个类的源码
public class CachingConfigurerSupport implements CachingConfigurer { // Spring's central cache manage SPI , @Override @Nullable public CacheManager cacheManager() { return null; } //key的生成策略 @Override @Nullable public KeyGenerator keyGenerator() { return null; } //Determine the Cache instance(s) to use for an intercepted method invocation. @Override @Nullable public CacheResolver cacheResolver() { return null; } //缓存错误处理 @Override @Nullable public CacheErrorHandler errorHandler() { return null; } }
RedisConfig类
@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport { @Bean RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory, MessageListenerAdapter listenerAdapter) { RedisMessageListenerContainer container = new RedisMessageListenerContainer(); container.setConnectionFactory(connectionFactory); container.addMessageListener(listenerAdapter, new PatternTopic("chat")); return container; } @Bean MessageListenerAdapter listenerAdapter(Receiver receiver) { return new MessageListenerAdapter(receiver, "receiveMessage"); } @Bean Receiver receiver(CountDownLatch latch) { return new Receiver(latch); } @Bean CountDownLatch latch() { return new CountDownLatch(1); } public class Receiver { private CountDownLatch latch; @Autowired public Receiver(CountDownLatch latch) { this.latch = latch; } public void receiveMessage(String message) { latch.countDown(); } } @Bean public KeyGenerator myKeyGenerator() { return 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(JSON.toJSONString(obj)); } return sb.toString(); } }; } /** * @param redisConnectionFactory * @return * @// TODO: 2018/4/27 redis fastjson序列化 */ @Bean @ConditionalOnMissingBean(name = "redisTemplate") public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) { RedisTemplate<Object, Object> template = new RedisTemplate<>(); //使用fastjson序列化 FastJsonRedisSerializer fastJsonRedisSerializer = new FastJsonRedisSerializer<>(Object.class); // 全局开启AutoType，不建议使用 // ParserConfig.getGlobalInstance().setAutoTypeSupport(true); // 建议使用这种方式，小范围指定白名单 ParserConfig.getGlobalInstance().addAccept("com.developlee.models."); // value值的序列化采用fastJsonRedisSerializer template.setValueSerializer(fastJsonRedisSerializer); template.setHashValueSerializer(fastJsonRedisSerializer); // key的序列化采用StringRedisSerializer template.setKeySerializer(new StringRedisSerializer()); template.setHashKeySerializer(new StringRedisSerializer()); template.setConnectionFactory(redisConnectionFactory); return template; } @Bean @ConditionalOnMissingBean(StringRedisTemplate.class) public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory redisConnectionFactory) { StringRedisTemplate template = new StringRedisTemplate(); template.setConnectionFactory(redisConnectionFactory); return template; } /** * @return * @// TODO: 2018/4/27 设置redis 缓存时间 5 分钟 */ @Bean public RedisCacheConfiguration redisCacheConfiguration() { FastJsonRedisSerializer<Object> fastJsonRedisSerializer = new FastJsonRedisSerializer<>(Object.class); RedisCacheConfiguration configuration = RedisCacheConfiguration.defaultCacheConfig(); configuration = configuration.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(fastJsonRedisSerializer)).entryTtl(Duration.ofMinutes(5)); return configuration; } }
这段代码中，重点关注对象是RedisTemplate 和StringRedisTemplate还有RedisMessageListenerContainer，RedisTemplate和StringRedisTemplate设置了一些序列化的参数和指定序列化的范围（主要为了防止黑客利用Redis的序列化漏洞），@ConditionalOnMissingBean注解的意思就是如果容器中没有这个类型Bean就选择当前Bean。RedisMessageListenerContainer是为Redis消息侦听器提供异步行为的容器，主要处理低层次的监听、转换和消息发送的细节。
再来看看application.xml我们的配置 , so easy~~
spring:redis:database: 0 # Redis数据库索引（默认为0）host: 192.168.0.100 # Redis服务器地址 （默认为127.0.0.1）port: 6379 # Redis服务器连接端口 （默认为6379） password: 123456 # Redis服务器连接密码（默认为空） timeout: 2000 # 连接超时时间（毫秒） cache: type: redis接下来我们就可以使用Redis缓存了,在Service层我们用注解@Cacheable来缓存查询的结果。
@Cacheable(value= "orderDetailCache", keyGenerator = "myKeyGenerator", unless = "#result eq null")public OrderDetailEntity findOrderDetail(OrderDetailEntity orderDetailEntity) { return orderDetailDao.findEntity(orderDetailEntity); }