spring redistemplate中setHashValueSerializer的设置

笔者曾经对redis键值使用了不同类型的序列化方法

用过默认值、JdkSerializationRedisSerializer、StringRedisSerializer还用改以下自定类型的序列化工具类（据说这个比Spring RedisTemplate的序列化、反序列化快）

import com.dyuproject.protostuff.LinkedBuffer;
import com.dyuproject.protostuff.ProtostuffIOUtil;
import com.dyuproject.protostuff.Schema;
import com.dyuproject.protostuff.runtime.RuntimeSchema;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.SerializationException;

public class ProtostuffSerializer implements RedisSerializer<Object> {

    private boolean isEmpty(byte[] data) {
        return (data == null || data.length == 0);
    }

    private final Schema<ProtoWrapper> schema;

    private final ProtoWrapper wrapper;

    private final LinkedBuffer buffer;

    public ProtostuffSerializer() {
        this.wrapper = new ProtoWrapper();
        this.schema = RuntimeSchema.getSchema(ProtoWrapper.class);
        this.buffer = LinkedBuffer.allocate(LinkedBuffer.DEFAULT_BUFFER_SIZE);
    }

    @Override
    public byte[] serialize(Object t) throws SerializationException {
        if (t == null) {
            return new byte[0];
        }
        wrapper.data = t;
        try {
            return ProtostuffIOUtil.toByteArray(wrapper, schema, buffer);
        } finally {
            buffer.clear();
        }
    }

    @Override
    public Object deserialize(byte[] bytes) throws SerializationException {
        if (isEmpty(bytes)) {
            return null;
        }

        ProtoWrapper newMessage = schema.newMessage();
        ProtostuffIOUtil.mergeFrom(bytes, newMessage, schema);
        return newMessage.data;
    }

    private static class ProtoWrapper {

        public Object data;

    }
}

遇到过以下异常：

hash操作：java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String，然后这次又换另外一个Hash的序列化类

template.setHashValueSerializer(new Jackson2JsonRedisSerializer<>(Object.class));

序列化后的缓存如下：

因为上次使用ProtostuffSerializer对Hash值进行序列化，进行以下操作报错了

HashOperations<String,String,T> hashOperations = redisTemplate.opsForHash();

        if(value instanceof Long || value instanceof Integer|| value instanceof Short||value instanceof Byte)
        {
            long longValue = ((Number) value).longValue();
            hashOperations.increment(key,field,longValue);
        }

        if(value instanceof Float ||value instanceof  Double)
        {
            double doubleValue = ((Number) value).doubleValue();
            Double returned = hashOperations.increment(key, field, -0.005);
        }
        return hashOperations;

报错如下：io.lettuce.core.RedisCommandExecutionException: ERR hash value is not a valid float

，因为经过ProtostuffSerializer序列化的hash值会变形，编程、\X0A=\X5A\X43\XC格式的数据，进行数值运算报错。

注意事项：redis端increment操作，只支持double和long，所以数据要进行相关转换。

比如笔者代码如下，就会报错：

 public <T> T getCacheHashValue(String key, String field, Class<T> targetClass) {
        HashOperations<String,String,T> hashOperations = redisTemplate.opsForHash();
        return hashOperations.get(key, field);
    }

传入

Float balance = cacheService.getCacheHashValue(cacheKey, "balance", Float.class);

报错：

Caused by: java.lang.ClassCastException: java.lang.Double cannot be cast to java.lang.Float

redisTemplate相关文章：

springboot项目中使用spring-data-Redis对map序列化时报错

使用redisTemplate存储数据,出现\xAC\xED\x00\x05t\x00

参考：

Spring-data-redis @Cacheable java.lang.ClassCastException: java.util.HashMap cannot be cast to java.lang.String