在SpringBoot中添加Redis及配置方法

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在实际的开发中，会有这样的场景。有一个微服务需要提供一个查询的服务，但是需要查询的数据库表的数据量十分庞大，查询所需要的时间很长。此时就可以考虑在项目中加入缓存。

引入依赖

在maven项目中引入如下依赖。并且需要在本地安装redis。

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-redis</artifactId>
  <version>2.0.5.RELEASE</version>
</dependency>

配置redis

在SpringBoot的配置文件中添加如下代码。

redis:
  host: 127.0.0.1
  port: 6379
  timeout: 5000
  database: 0
  jedis:
   pool:
    max-idle: 8
    max-wait:
    min-idle: 0

添加redis配置文件

新建名为RedisConfig的配置类。

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheWriter;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;

import java.time.Duration;

/**
 * RedisConfig
 *
 * @author detectiveHLH
 * @date 2018-10-11 14:39
 **/
@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {
  @Bean
  @Override
  public KeyGenerator keyGenerator() {
    return (target, method, params) -> {
      StringBuilder sb = new StringBuilder();
      sb.append(target.getClass().getName());
      sb.append(method.getName());
      for (Object obj : params) {
        sb.append(obj.toString());
      }
      return sb.toString();
    };
  }

  @Bean
  public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory) {
    ObjectMapper om = new ObjectMapper();
    om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
    om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
    //redis序列化
    Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
    jackson2JsonRedisSerializer.setObjectMapper(om);

    StringRedisTemplate template = new StringRedisTemplate(factory);
    template.setValueSerializer(jackson2JsonRedisSerializer);
    template.afterPropertiesSet();
    return template;
  }

  /**
   * 自定义CacheManager
   */
  @Bean
  public CacheManager cacheManager(RedisTemplate redisTemplate) {
    //全局redis缓存过期时间
    RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofDays(1));
    RedisCacheWriter redisCacheWriter = RedisCacheWriter.nonLockingRedisCacheWriter(redisTemplate.getConnectionFactory());
    return new RedisCacheManager(redisCacheWriter, redisCacheConfiguration);
  }
}

添加缓存配置

在项目的service层中的实现类中，添加@Cacheable注解。

import java.util.HashMap;

/**
 * UserLoginServiceImpl
 *
 * @author detectiveHLH
 * @date 2018-10-10 17:20
 **/
@Service
public class UserLoginServiceImpl implements UserLoginService {
  @Autowired
  private UserLoginMapper userLoginMapper;

  @Override
  @Cacheable(value = "usercache")
  public HashMap getByUserName(String userName) {
    System.out.println("此时没有走缓存");
    return userLoginMapper.getByUserName(userName);
  }
}

然后调用一次该接口。就可以在redis中看到如下的key。