場景：要獲取某個Json資料，但不知道Json資料的key。如：{"item_key1":"item_value1","item_key2":"item_value2","item_key3":"item_value3"}
解決：關鍵是如何獲取到key，有了key，就可以獲取到value了。可用通過getMemberNames函式獲取key，之後通過key獲取value

string strJson = "{"item_key1":"item_value1","item_key2":"item_value2","item_key3":"item_value3"}";
Json::Value valRoot;  
 

Json::Reader reader;  

        if (!reader.parse(strJson, valRoot))  
        {  
            return JSON_PARSE_ERR;  
        }  

        Json::Value::Members members;  
        members = valRoot.getMemberNames();   // 獲取所有key的值
        for (Json::Value::Members::iterator iterMember = members.begin
 
(); iterMember != members.end(); iterMember++)   // 遍歷每個key
        {  
            std::string strKey = *iterMember;  
            if (valRoot[strKey.c_str()].isString())  
            {  
                std::string strVal = valRoot[strKey.c_str()].asString();  
                std::cout<<strKey.c
 
_str()<<":"<<strVal.c_str()<<std::endl;  
            }  
            else if (valRoot[strKey.c_str()].isInt())  
            {  
                int iVal = valRoot[strKey.c_str()].asInt();  
                std::cout<<strKey.c_str()<<":"<<iVal<<std::endl;  
            }  
            else if (valRoot[strKey.c_str()].isDouble())  
            {  
                double dVal = valRoot[strKey.c_str()].asDouble();  
                std::cout<<strKey.c_str()<<":"<<dVal<<std::endl;  
            }  
            else  
            {  
                std::string strVal = valRoot[strKey.c_str()].toStyledString();  
                std::cout<<strKey.c_str()<<":"<<strVal.c_str()<<std::endl;  
            }  
        }