springboot基础(81):设置redis序列化器

前言

序列化器有多种，默认的序列是JdkSerializationRedisSerializer ，通常性能较差，相对而言，我们会使用性能最好的Kryo序列化器来序列化。

redis如何配置Kryo序列化器

1. 导入依赖

 <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
         <!-- https://mvnrepository.com/artifact/com.esotericsoftware/kryo -->
        <dependency>
            <groupId>com.esotericsoftware</groupId>
            <artifactId>kryo</artifactId>
            <version>5.5.0</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.xerial.snappy/snappy-java -->
        <dependency>
            <groupId>org.xerial.snappy</groupId>
            <artifactId>snappy-java</artifactId>
            <version>1.1.10.5</version>
        </dependency>

2. 添加序列化器

import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;
import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.SerializationException;

import java.io.ByteArrayOutputStream;

@Slf4j
public class KryoRedisSerializer<T> implements RedisSerializer<T> {

    public static final byte[] EMPTY_BYTE_ARRAY = new byte[0];

    private static final ThreadLocal<Kryo> KYROS = ThreadLocal.withInitial(Kryo::new);

    private Class<T> clazz;

    public KryoRedisSerializer(Class<T> clazz) {
        super();
        this.clazz = clazz;
    }

    @Override
    public byte[] serialize(T t) throws SerializationException {
        if (t == null) {
            return EMPTY_BYTE_ARRAY;
        }

        Kryo kryo = KYROS.get();
        kryo.setReferences(false);
        kryo.register(clazz);

        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
             Output output = new Output(baos)) {
            kryo.writeClassAndObject(output, t);
            output.flush();
            return baos.toByteArray();
        } catch (Exception e) {
            log.error(e.getMessage(), e);
        }

        return EMPTY_BYTE_ARRAY;
    }

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

        Kryo kryo = KYROS.get();
        kryo.setReferences(false);
        kryo.register(clazz);
        try (Input input = new Input(bytes)) {
            return (T) kryo.readClassAndObject(input);
        } catch (Exception e) {
            log.error(e.getMessage(), e);
        }

        return null;
    }
}

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.SerializationUtils;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.SerializationException;
import org.xerial.snappy.Snappy;

import java.io.Serializable;

@Slf4j
public class SnappyRedisSerializer<T> implements RedisSerializer<T> {

    private RedisSerializer<T> innerSerializer;

    public SnappyRedisSerializer() {

    }

    public SnappyRedisSerializer(RedisSerializer<T> innerSerializer) {
        this.innerSerializer = innerSerializer;
    }

    @Override
    public byte[] serialize(T object) throws SerializationException {
        try {
            byte[] bytes = innerSerializer != null ? innerSerializer.serialize(object)
                    : SerializationUtils.serialize((Serializable) object);
            return Snappy.compress(bytes);
        } catch (Exception e) {
            throw new SerializationException(e.getMessage(), e);
        }
    }

    @Override
    public T deserialize(byte[] bytes) throws SerializationException {
        try {
            if (bytes == null || bytes.length <= 0) {
                return null;
            }
            byte[] bos = Snappy.uncompress(bytes);
            return (T) (innerSerializer != null ?
                    innerSerializer.deserialize(bos) : SerializationUtils.deserialize(bos));
        } catch (Exception e) {
            throw new SerializationException(e.getMessage(), e);
        }
    }
}

3. 配置序列化 即可

@Configuration
public class RedisConfig {

    @Bean(name = "redisTemplate")
    public RedisTemplate<String, Object> getRedisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<String, Object>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        redisTemplate.setKeySerializer(new StringRedisSerializer()); // key的序列化类型
        redisTemplate.setValueSerializer(new SnappyRedisSerializer<>(new KryoRedisSerializer<>(Object.class)));
        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }
}

为了查看缓存的key便利，通常将key的序列化器设置为StringRedisSerializer，而不使用其它序列化器。