[alibaba/fastjson]泛型解析时偶尔出现com.alibaba.fastjson.JSONObject cannot be cast to

现象：每次上线重启机器之后，定时任务处理某个业务总会出现异常java.lang.ClassCastException: com.alibaba.fastjson.JSONObject cannot be cast to com.jiedaibao.umg.consumer.third.p2proute.rsp.PrtUnBindRsp

• 分析：代码都是同一套，对出现问题机器重启之后，定时任务跑到其他机子上去后又正常了
• 原因：ParserConfig.Java，getDeserializer缓存导致

疑问1： 为什么String转成PtpRouteBaseRsp < PrtUnBindRsp > 时，ParseConfig要取Class<?>，而这个class则是rawType，却不直接取type，PtpRouteBaseRsp < PrtUnBindRsp > 。如下ParseConfig类中getDeserializer(Class<?> clazz, Type type) 方法

`

     if (type instanceof ParameterizedType) {

        Type rawType = ((ParameterizedType) type).getRawType();
        if (rawType instanceof Class<?>) {
            return getDeserializer((Class<?>) rawType, type);
        } else {
            return getDeserializer(rawType);
        }
    }

    if (type instanceof WildcardType || type instanceof TypeVariable || type instanceof ParameterizedType) {
        derializer = derializers.get(clazz);
    }`

疑问2： ParseConfig中的derializers还有作用域吗，我自己试了几个案例如下，结果： （1）当在main函数执行带泛型，不带泛型，带泛型，分别是true,true,false，说明第三个使用了第二个不带泛型的缓存。 （2）当把带泛型和不带泛型分别放在bbb和aaa方法里，则执行之后结果都是true 麻烦解释下

`

public static void main(String[] args) {

    //true
    String a ="{\"error\":{\"returnCode\":\"0\",\"returnMessage\":\"操作成功\",\"returnUserMessage\":\"操作成功\"},\"data\":{\"errCode\":\"\"},\"logid\":\"6469558a598c04a139a5111908890102\"}";
    PtpRouteBaseRsp<PrtUnBindRsp> itemResult2= JSON.parseObject(a,new TypeReference<PtpRouteBaseRsp<PrtUnBindRsp>>(){});
    System.out.println(itemResult2.getData() instanceof PrtUnBindRsp);

    //true
    String b ="{\"error\":{\"returnCode\":\"0\",\"returnMessage\":\"操作成功\",\"returnUserMessage\":\"操作成功\"},\"data\":{},\"logid\":\"6469558f598c14c4b345129804913202\"}";
    PtpRouteBaseRsp resultFromClass2 = JSON.parseObject(b, new TypeReference<PtpRouteBaseRsp>() {});
    System.out.println(resultFromClass2.getData() instanceof JSON);

    //false
    String c ="{\"error\":{\"returnCode\":\"0\",\"returnMessage\":\"操作成功\",\"returnUserMessage\":\"操作成功\"},\"data\":{\"errCode\":\"\"},\"logid\":\"6469558a598c04a139a5111908890102\"}";
    PtpRouteBaseRsp<PrtUnBindRsp> itemResult3= JSON.parseObject(c,new TypeReference<PtpRouteBaseRsp<PrtUnBindRsp>>(){});
    System.out.println(itemResult3.getData() instanceof PrtUnBindRsp);

 /*   //true
    bbb();
    //true
    aaa();
    //true
    bbb();*/

}
private static void aaa(){
    String b ="{\"error\":{\"returnCode\":\"0\",\"returnMessage\":\"操作成功\",\"returnUserMessage\":\"操作成功\"},\"data\":{},\"logid\":\"6469558f598c14c4b345129804913202\"}";
    PtpRouteBaseRsp resultFromClass2 = JSON.parseObject(b, new TypeReference<PtpRouteBaseRsp>() {});
    System.out.println(resultFromClass2.getData() instanceof JSON);
}
private static void bbb(){
    String a ="{\"error\":{\"returnCode\":\"0\",\"returnMessage\":\"操作成功\",\"returnUserMessage\":\"操作成功\"},\"data\":{\"errCode\":\"\"},\"logid\":\"6469558a598c04a139a5111908890102\"}";
    PtpRouteBaseRsp<PrtUnBindRsp> itemResult2= JSON.parseObject(a,new TypeReference<PtpRouteBaseRsp<PrtUnBindRsp>>(){});
    System.out.println(itemResult2.getData() instanceof PrtUnBindRsp);
}

`