JSONCPP解析时比较麻烦，要判这判那的，于是直接简单封装了一个helper，如果要想面向对象可以直接改成类的静态成员。

jsoncpp_helper.h

#pragma once

#if( defined(WIN32) || defined(WIN64) )
#include "jsoncpp/include/json/json.h"
#else
#include "jsoncpp/json/json.h"
#endif

#include <string>

bool _TrimJsonValueString(Json::Value &Root,const char* pszNodeName,std::string& strOut);
bool _TrimJsonValueInt(Json::Value &Root,int& nOut,bool bFromString = false);
bool _TrimJsonValueUint(Json::Value &Root,unsigned int& nOut,bool bFromString = false);
bool _TrimJsonValueInt64(Json::Value &Root,int64_t& nOut);
bool _TrimJsonValueUint64(Json::Value &Root,uint64_t& nOut);

#include "jsoncpp_helper.h"


bool _TrimJsonValueString(Json::Value &Root,std::string& strOut)
{
	if (Root.isMember(pszNodeName) && !Root[pszNodeName].isNull() && Root[pszNodeName].isString())
	{
		strOut = Root[pszNodeName].asString();
		return true;
	}

	return false;
}

bool _TrimJsonValueInt(Json::Value &Root,bool bFromString)
{
	if (bFromString)
	{
		std::string strTmp;
		if (!_TrimJsonValueString(Root,pszNodeName,strTmp)) return false;
		nOut = atoi(strTmp.c_str());
		return true;
	}

	if (Root.isMember(pszNodeName) && !Root[pszNodeName].isNull() && Root[pszNodeName].isInt())
	{
		nOut = Root[pszNodeName].asInt();
		return true;
	}

	return false;
}

bool _TrimJsonValueUint(Json::Value &Root,strTmp)) return false;
		nOut = atoi(strTmp.c_str());
		return true;
	}

	if (Root.isMember(pszNodeName) && !Root[pszNodeName].isNull() && Root[pszNodeName].isInt())
	{
		nOut = Root[pszNodeName].asInt();
		return true;
	}

	return false;
}

bool _TrimJsonValueInt64(Json::Value &Root,int64_t& nOut)
{
	std::string strTmp;
	if (!_TrimJsonValueString(Root,strTmp)) return false;
	nOut = atoll(strTmp.c_str());
	return true;
}

bool _TrimJsonValueUint64(Json::Value &Root,uint64_t& nOut)
{
	std::string strTmp;
	if (!_TrimJsonValueString(Root,strTmp)) return false;
	nOut = atoll(strTmp.c_str());
	return true;
}