[Redis]_**_cannot_be_cast_to_java.lang.String_redis

先上问题：

java.lang.ClassCastException: com.ppdai.cbd.ddp.thirdparty.contract.bhxtzx.BHXTZXTask cannot be cast to java.lang.String
    at org.springframework.data.redis.serializer.StringRedisSerializer.serialize(StringRedisSerializer.java:33)
    at org.springframework.data.redis.core.AbstractOperations.rawValue(AbstractOperations.java:117)
    at org.springframework.data.redis.core.DefaultListOperations.leftPush(DefaultListOperations.java:71)
    at org.springframework.data.redis.core.DefaultBoundListOperations.leftPush(DefaultBoundListOperations.java:60)
    at com.ppdai.realtime.datachannel.pullservice.entity.RedisQueue.pushFromHead(RedisQueue.java:63)
    at com.ppdai.realtime.datachannel.pullservice.redisconfig.RedisTaskSender.sendTask(RedisTaskSender.java:35)
    at com.ppdai.realtime.datachannel.pullservice.redisconfig.RedisTaskSender$sendTask.call(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
    at com.ppdai.realtime.datachannel.pullservice.dataproviders.bohai.BohaiQueryProvider.afterGetData(BohaiQueryProvider.groovy:395)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:210)
    at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.callCurrent(PogoMetaMethodSite.java:59)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:52)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:154)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:166)

看问题原因是序列化对象的时候使用的是?StringRedisSerializer, 本来以为是因为AutoConfig 导致加载了系统默认的RedisTemplate, 而自己定义了RedisTemplate没有加载,

但是非常疑惑的一点是默认的RedisTemplate使用的是?JdkSerializationRedisSerializer（如下代码）,上面异常报的是使用redis value 使用StringRedisSerializer 导致的类型转化失败

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(this);
    }

    initialized = true;
}

private Long incr(String key, long delta){
    RedisTemplate redisTemplate = getRedisTemplate()
    ValueOperations operations = redisTemplate.opsForValue()
    redisTemplate.setKeySerializer(new StringRedisSerializer())
        redisTemplate.setValueSerializer(new StringRedisSerializer())
    return operations.increment(key, delta)
}

原来就是这里搞得鬼,将redisTemplate的ValueSerializer设置成了?StringRedisSerializer ,StringRedisSerializer参数是String类型的,所以呢就出现了类型转化错误.

附说明

redisTemplate需要序列化key,value,hashkey,hashvalue,? 提供了很多序列化工具,什么Jackson、FastJson、JDKSerialization 也可以自己定义.

redisTamplate默认这四种都使用JDKSerialization做序列化,如果没有提供定义默认都用JDK.

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