谈谈spring-data-redis遇到的问题

java
java, redis, spring

[TOC]

1. key序列化问题

使用spring-data-redis中的redisTemplate存储key-value，然后使用redis-cli去查询时查询不到相应的key。使用keys *时发现redis中key的前缀多了一些字符

\xac\xed\x00\x05t\x00\x0e

问题关键

使用spring-data-redis，默认情况下使用的是org.springframework.data.redis.serializer.JdkSerializationRedisSerializer来进行序列化key

我们看看关键代码 RedisTemplate

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public void afterPropertiesSet() {

        super.afterPropertiesSet();

        boolean defaultUsed = false;

        if (defaultSerializer == null) {

            defaultSerializer = new JdkSerializationRedisSerializer(
                    classLoader != null ? classLoader : this.getClass().getClassLoader());
        }

        if (enableDefaultSerializer) {

            if (keySerializer == null) {
                keySerializer = defaultSerializer;
                defaultUsed = true;
            }
            if (valueSerializer == null) {
                valueSerializer = defaultSerializer;
                defaultUsed = true;
            }
            if (hashKeySerializer == null) {
                hashKeySerializer = defaultSerializer;
                defaultUsed = true;
            }
            if (hashValueSerializer == null) {
                hashValueSerializer = defaultSerializer;
                defaultUsed = true;
            }
        }

        if (enableDefaultSerializer && defaultUsed) {
            Assert.notNull(defaultSerializer, "default serializer null and not all serializers initialized");
        }

        if (scriptExecutor == null) {
            this.scriptExecutor = new DefaultScriptExecutor<K>(this);
        }

        initialized = true;
    }

解决问题

手动设置key的序列化方式为StringRedisSerializer

看代码

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@Bean
public RedisTemplate<String, ?> redisTemplate(RedisConnectionFactory factory) {
    RedisTemplate<String, Object> redisTemplate = new RedisTemplate();
    redisTemplate.setConnectionFactory(factory);
    RedisSerializer<String> stringRedisSerializer = new StringRedisSerializer();
    redisTemplate.setKeySerializer(stringRedisSerializer);
  	redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());
    return redisTemplate;
}

2. value 序列化问题

我们在使用无参构造GenericJackson2JsonRedisSerializer序列化对象时，序列化出来的值是这样的

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{
  "@class": "com.xxx.MenuTask",
  "taskId": "1617776640",
  "planId": "10000000",
  "createTime": [
    "java.util.Date",
    1500540438240
  ],
  "execDate": [
    "java.util.Date",
    1500480000000
  ],
  "status": 0,
  "totals": {
    "@class": "java.util.HashMap",
    "35430d2a56ae508f24a76a68e71b9f53": 1500,
    "75aa86c5a85f65687c95444655c51de9": 500,
    "ab90efa7a0079b88f224a296b211c209": 1000
  }
}

这样的json格式使用其他的json序列化时会出现无法解析的错误，如fastjson解析时会抛出异常

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com.alibaba.fastjson.JSONException: parse error
	at com.alibaba.fastjson.serializer.DateCodec.cast(DateCodec.java:206)
	at com.alibaba.fastjson.parser.deserializer.AbstractDateDeserializer.deserialze(AbstractDateDeserializer.java:142)
	at com.alibaba.fastjson.parser.deserializer.AbstractDateDeserializer.deserialze(AbstractDateDeserializer.java:19)
	at com.alibaba.fastjson.parser.deserializer.DefaultFieldDeserializer.parseField(DefaultFieldDeserializer.java:71)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.parseField(JavaBeanDeserializer.java:790)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.deserialze(JavaBeanDeserializer.java:595)

主要原因是因为Date格式不正确，应该是一个long类型的数字，而不是一个数组

问题关键

我们来分析一下源码

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public class GenericJackson2JsonRedisSerializer implements RedisSerializer<Object> {

	private final ObjectMapper mapper;

	/**
	 * Creates {@link GenericJackson2JsonRedisSerializer} and configures {@link ObjectMapper} for default typing.
	 */
	public GenericJackson2JsonRedisSerializer() {
		this((String) null);
	}

	public GenericJackson2JsonRedisSerializer(String classPropertyTypeName) {

		this(new ObjectMapper());
//------------------------ start ------------------------
		mapper.registerModule(new SimpleModule().addSerializer(new NullValueSerializer(classPropertyTypeName)));

		if (StringUtils.hasText(classPropertyTypeName)) {
			mapper.enableDefaultTypingAsProperty(DefaultTyping.NON_FINAL, classPropertyTypeName);
		} else {
			mapper.enableDefaultTyping(DefaultTyping.NON_FINAL, As.PROPERTY);
		}
//------------------------ end ------------------------
	}
	
	public GenericJackson2JsonRedisSerializer(ObjectMapper mapper) {
		Assert.notNull(mapper, "ObjectMapper must not be null!");
		this.mapper = mapper;
	}
	...
	...
}

原因所在地方 // —- start —- // —- end —-之间的那段代码 源码的63-69行，这里会将属性的类型写到json中。

解决问题

手动设置一个ObjectMapper，这样redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer(new ObjectMapper()));

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@Bean
public RedisTemplate<String, ?> redisTemplate(RedisConnectionFactory factory) {
    RedisTemplate<String, Object> redisTemplate = new RedisTemplate();
    redisTemplate.setConnectionFactory(factory);
    RedisSerializer<String> stringRedisSerializer = new StringRedisSerializer();
    redisTemplate.setKeySerializer(stringRedisSerializer);
    redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer(new ObjectMapper()));
    return redisTemplate;
}
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本文标题：谈谈spring-data-redis遇到的问题
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