Spring Boot下配置Redis缓存

记录配置过程

题图：made by Keynote

一、添加Redis支持

在build.gradle文件的dependencies模块下添加

compile("org.springframework.boot:spring-boot-starter-redis")

二、配置Redis

想要使得redis可用，我们首先需要为缓存配置一个CacheManager、创建连接用的ConnectionFactory以及与Redis交互用的template（Spring的特点^_^）。当然，如果需要自定义主键，还要配置一个KeyGenerator，否则默认使用参数名作为主键。

下面示例代码中RedisProperties类用来读取配置信息，RedisConfiguration用来对redis进行配置。

@Configuration
@EnableCaching
public class RedisConfiguration extends CachingConfigurerSupport {
    @Autowired
    private RedisProperties redisProperties;

    @Bean
    public KeyGenerator keyGenerator() {
        return new KeyGenerator() {
            @Override
            public Object generate(Object target, Method method, Object... params) {
                if (params.length == 0) {
                    return Constants.CACHE_KEY_PREFIX + method.getName();
                }
                if (params.length == 1) {
                    Object param = params[0];
                    if (param != null && !param.getClass().isArray()) {
                        return Constants.CACHE_KEY_PREFIX + method.getName() + "_" + param;
                    }
                }
                return Constants.CACHE_KEY_PREFIX + method.getName() + " [" + StringUtils.arrayToCommaDelimitedString(params) + "]";
            }
        };
    }

    @Bean
    public CacheManager cacheManager(RedisTemplate redisTemplate) {
        RedisCacheManager redisCacheManager = new RedisCacheManager(redisTemplate);
        redisCacheManager.setDefaultExpiration(redisProperties.getExpire());
        return redisCacheManager;
    }

    @Bean(name = "redisTemplate")
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(factory);

        redisTemplate.setValueSerializer(new RedisSerializer<Object>() {
            @Override
            public byte[] serialize(Object object) throws SerializationException {
                if (object == null) {
                    return new byte[0];
                }
                if (!(object instanceof Serializable)) {
                    throw new IllegalArgumentException("RedisSerializer.serialize requires a Serializable payload "
                            + "but received an object of type [" + object.getClass().getName() + "]");
                }
                return SerializationUtils.serialize((Serializable) object);
            }

            @Override
            public Object deserialize(byte[] bytes) throws SerializationException {
                if (bytes == null || bytes.length == 0) {
                    return null;
                }
                return SerializationUtils.deserialize(bytes);
            }
        });

        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }

    @Bean
    public JedisConnectionFactory redisConnectionFactory() {
        JedisConnectionFactory redisConnectionFactory = new JedisConnectionFactory();

        // Defaults
        redisConnectionFactory.setHostName(redisProperties.getHost());
        redisConnectionFactory.setPort(redisProperties.getPort());
        redisConnectionFactory.setDatabase(redisProperties.getIndex());
        redisConnectionFactory.setPassword(redisProperties.getPassword());
        return redisConnectionFactory;
    }
}

@Component
@ConfigurationProperties(prefix = "redis")
public class RedisProperties {

    private String host;
    private int port;
    private String password;
    private int expire;
    private int index;

    public String getHost() {
        return host;
    }

    public void setHost(String host) {
        this.host = host;
    }

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public int getExpire() {
        return expire;
    }

    public void setExpire(int expire) {
        this.expire = expire;
    }

    public int getIndex() {
        return index;
    }

    public void setIndex(int index) {
        this.index = index;
    }

}

三、Redis服务器配置

在application.yml文件中进行配置

redis:
    host: 127.0.0.1
    port: 6379
    password: xxxxxxx
    expire: 120
    index: 11

四、应用

1.@Cacheable

通过以上配置，spring会自动检测到redis的缓存配置。
在需要缓存结果的方法上添加@Cacheable注解，即可实现自动使用redis进行缓存。

2.redisTemplate

某些情况下，@Cacheable注解有可能不适用，也可以直接获取redisTemplate来直接操作redis缓存。
与JDBCTemplate等Template相同，RedisTemplate也对redis的相关操作进行很好的封装，使用起来十分方便。
因为redisTemplate已经注册为Spring管理的Bean，所以可以通过getBean()方法直接获取。

五、参考文章

Caching Data in Spring Using Redis