springboot集成Redis

springboot集成Redis

前言

Redis是目前使用的非常广泛的内存数据库，相比memcached，它支持更加丰富的数据类型。本来简要介绍在springboot中使用redis的方法。

如何使用？

1、引入spring-boot-starter-redis

<!-- redis -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

2、在application.properties增加Redis的配置

# 使用的数据库（0-15），默认为0
spring.redis.database=0  
# Redis服务器地址
spring.redis.host=127.0.0.1
# Redis服务器连接端口
spring.redis.port=6379  
# Redis服务器连接密码（默认为空）
spring.redis.password=  

3、使用

@Autowired
private StringRedisTemplate stringRedisTemplate;

@RequestMapping(value = "/redis/{key}/{value}",method = RequestMethod.GET)
@ResponseBody
public String redisTest(@PathVariable String key,@PathVariable String value) {
    String redisValue = stringRedisTemplate.opsForValue().get(key);
    if (StringUtils.isEmpty(redisValue)) {
        stringRedisTemplate.opsForValue().set(key,value);
        return "操作成功！";
    }

    if (!redisValue.equals(value)) {
        stringRedisTemplate.opsForValue().set(key,value);
        return "操作成功！";
    }

    return String.format("redis中已存在[key=%s,value=%s]的数据！",key,value);
}

随便写的一个例子。

4、Sentinel模式配置
上面的是单机的一个配置，如果是主从，参考：

#redis配置
spring.redis.database=0
spring.redis.password=system
spring.redis.pool.max-idle=10
spring.redis.pool.min-idle=0
spring.redis.pool.max-active=10
spring.redis.pool.max-wait=-1
spring.redis.sentinel.master=mymaster
spring.redis.sentinel.nodes=192.168.74.135:26379,192.168.74.136:26379

5、redis的全部配置：

# REDIS (RedisProperties)
spring.redis.cluster.max-redirects= # Maximum number of redirects to follow when executing commands across the cluster.
spring.redis.cluster.nodes= # Comma-separated list of "host:port" pairs to bootstrap from.
spring.redis.database=0 # Database index used by the connection factory.
spring.redis.url= # Connection URL, will override host, port and password (user will be ignored), e.g. redis://user:password@example.com:6379
spring.redis.host=localhost # Redis server host.
spring.redis.password= # Login password of the redis server.
spring.redis.ssl=false # Enable SSL support.
spring.redis.pool.max-active=8 # Max number of connections that can be allocated by the pool at a given time. Use a negative value for no limit.
spring.redis.pool.max-idle=8 # Max number of "idle" connections in the pool. Use a negative value to indicate an unlimited number of idle connections.
spring.redis.pool.max-wait=-1 # Maximum amount of time (in milliseconds) a connection allocation should block before throwing an exception when the pool is exhausted. Use a negative value to block indefinitely.
spring.redis.pool.min-idle=0 # Target for the minimum number of idle connections to maintain in the pool. This setting only has an effect if it is positive.
spring.redis.port=6379 # Redis server port.
spring.redis.sentinel.master= # Name of Redis server.
spring.redis.sentinel.nodes= # Comma-separated list of host:port pairs.
spring.redis.timeout=0 # Connection timeout in milliseconds.

6、使用redis自动缓存数据
可以把一些经常查询的数据放到redis缓存起来，不用每次都查询数据库。
上面是手动缓存到redis，这里介绍一下如何自动数据缓存到redis。

a.增加一个redis的配置类：

@Configuration
@EnableCaching
public class RedisConfig{

    @Bean
    public KeyGenerator redisKeyGenerator(){
        return new KeyGenerator() {
            @Override
            public Object generate(Object target, Method method, Object... 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 CacheManager cacheManager(
            @SuppressWarnings("rawtypes") RedisTemplate redisTemplate) {
        return new RedisCacheManager(redisTemplate);
    }

    @Bean
    public RedisTemplate<String, String> redisTemplate(
            RedisConnectionFactory factory) {
        StringRedisTemplate template = new StringRedisTemplate(factory);
        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);
        template.setValueSerializer(jackson2JsonRedisSerializer);
        template.afterPropertiesSet();
        return template;
    }
}

b.在需要缓存的service方法上加上注解：

@Cacheable(value = "userCache")
public TUser findById(String id) {
    return this.userRepository.findOne(id);
}

这样，就只有redis没有相应的Key的时候才会查询数据库。

我们看下redis：

图中，redis的key就是你的参数。