轉載：C++通過HTTP請求Get或Post方式請求Json數據
最近在工作中，由于合作商只提供uRL，我這邊需要通過HTTP請求Get或Post方式請求Json數據，然后解析JSON格式，解析json我使用的第三方庫jsoncpp，代碼如下

#pragma once #include <iostream> #include <windows.h> #include <wininet.h>using namespace std;//每次讀取的字節數 #define READ_BUFFER_SIZE 4096enum HttpInterfaceError {Hir_Success = 0, //成功Hir_InitErr, //初始化失敗Hir_ConnectErr, //連接HTTP服務器失敗Hir_SendErr, //發送請求失敗Hir_QueryErr, //查詢HTTP請求頭失敗Hir_404, //頁面不存在Hir_IllegalUrl, //無效的URLHir_CreateFileErr, //創建文件失敗Hir_DownloadErr, //下載失敗Hir_QueryIPErr, //獲取域名對應的地址失敗Hir_SocketErr, //套接字錯誤Hir_UserCancel, //用戶取消下載Hir_BufferErr, //文件太大，緩沖區不足Hir_HeaderErr, //HTTP請求頭錯誤Hir_ParamErr, //參數錯誤，空指針，空字符Hir_UnknowErr, }; enum HttpRequest {Hr_Get,Hr_Post }; class CWininetHttp { public:CWininetHttp(void);~CWininetHttp(void);public:// 通過HTTP請求：Get或Post方式獲取JSON信息 [3/14/2017/shike]const std::string RequestJsonInfo( const std::string& strUrl,HttpRequest type = Hr_Get, std::string lpHeader = "",std::string lpPostData = ""); protected:// 解析卡口Json數據 [3/14/2017/shike]void ParseJsonInfo(const std::string &strJsonInfo);// 關閉句柄 [3/14/2017/shike]void Release();// 釋放句柄 [3/14/2017/shike]void ReleaseHandle( HINTERNET& hInternet );// 解析URL地址 [3/14/2017/shike]void ParseURLWeb( std::string strUrl, std::string& strHostName, std::string& strPageName, WORD& sPort);// UTF-8轉為GBK2312 [3/14/2017/shike]char* UtfToGbk(const char* utf8);private:HINTERNET m_hSession;HINTERNET m_hConnect;HINTERNET m_hRequest;HttpInterfaceError m_error; }; /************************************************* File name : WininetHttp.cpp Description: 通過URL訪問HTTP請求方式獲取JSON Author : shike Version : 1.0 Date : 2016/10/27 Copyright (C) 2016 - All Rights Reserved *************************************************/ #include "WininetHttp.h" //#include "Common.h" #include <json/json.h> #include <fstream> #include "common/CVLog.h" #pragma comment(lib, "Wininet.lib") #include <tchar.h> using namespace std;extern CCVLog CVLog;CWininetHttp::CWininetHttp(void):m_hSession(NULL),m_hConnect(NULL),m_hRequest(NULL) { }CWininetHttp::~CWininetHttp(void) {Release(); }// 通過HTTP請求：Get或Post方式獲取JSON信息 [3/14/2017/shike] const std::string CWininetHttp::RequestJsonInfo(const std::string& lpUrl,HttpRequest type/* = Hr_Get*/,std::string strHeader/*=""*/,std::string strPostData/*=""*/) {std::string strRet = "";try{if ( lpUrl.empty()){throw Hir_ParamErr;}Release();m_hSession = InternetOpen(_T("Http-connect"), INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, NULL); //局部if ( NULL == m_hSession ){throw Hir_InitErr;}INTERNET_PORT port = INTERNET_DEFAULT_HTTP_PORT;std::string strHostName = "";std::string strPageName = "";ParseURLWeb(lpUrl, strHostName, strPageName, port);printf("lpUrl:%s,\nstrHostName:%s,\nstrPageName:%s,\nport:%d\n",lpUrl.c_str(),strHostName.c_str(),strPageName.c_str(),(int)port);m_hConnect = InternetConnectA(m_hSession, strHostName.c_str(), port, NULL, NULL, INTERNET_SERVICE_HTTP, NULL, NULL);if ( NULL == m_hConnect ){throw Hir_ConnectErr;}std::string strRequestType;if ( Hr_Get == type ){strRequestType = "GET";}else{strRequestType = "POST";}m_hRequest = HttpOpenRequestA(m_hConnect,strRequestType.c_str(), strPageName.c_str(),"HTTP/1.1", NULL, NULL, INTERNET_FLAG_RELOAD, NULL);if ( NULL == m_hRequest ){throw Hir_InitErr;}DWORD dwHeaderSize = (strHeader.empty()) ? 0 : strlen(strHeader.c_str());BOOL bRet = FALSE;if ( Hr_Get == type ){bRet = HttpSendRequestA(m_hRequest,strHeader.c_str(),dwHeaderSize,NULL, 0);}else{DWORD dwSize = (strPostData.empty()) ? 0 : strlen(strPostData.c_str());bRet = HttpSendRequestA(m_hRequest,strHeader.c_str(),dwHeaderSize,(LPVOID)strPostData.c_str(), dwSize);}if ( !bRet ){throw Hir_SendErr;}char szBuffer[READ_BUFFER_SIZE + 1] = {0};DWORD dwReadSize = READ_BUFFER_SIZE;if ( !HttpQueryInfoA(m_hRequest, HTTP_QUERY_RAW_HEADERS, szBuffer, &dwReadSize, NULL) ){throw Hir_QueryErr;}if ( NULL != strstr(szBuffer, "404") ){throw Hir_404;}while( true ){bRet = InternetReadFile(m_hRequest, szBuffer, READ_BUFFER_SIZE, &dwReadSize);if ( !bRet || (0 == dwReadSize) ){break;}szBuffer[dwReadSize]='\0';strRet.append(szBuffer);}}catch(HttpInterfaceError error){m_error = error;}return std::move(strRet); }// 解析Json數據 [11/8/2016/shike] void CWininetHttp::ParseJsonInfo(const std::string &strJsonInfo) {Json::Reader reader; //解析json用Json::ReaderJson::Value value; //可以代表任意類型if (!reader.parse(strJsonInfo, value)) { CVLog.LogMessage(LOG_LEVEL_ERROR,"[CXLDbDataMgr::GetVideoGisData] Video Gis parse data error...");}if (!value["result"].isNull()) {int nSize = value["result"].size();for(int nPos = 0; nPos < nSize; ++nPos) //對數據數組進行遍歷{//PGCARDDEVDATA stru ;//stru.strCardName = value["result"][nPos]["tollgateName"].asString();//stru.strCardCode = value["result"][nPos]["tollgateCode"].asString();//std::string strCDNum = value["result"][nPos]["laneNumber"].asString(); //增加:車道總數//stru.nLaneNum = atoi(strCDNum.c_str());//std::string strLaneDir = value["result"][nPos]["laneDir"].asString(); //增加:車道方向,進行規則轉換//stru.strLaneDir = TransformLaneDir(strLaneDir);//stru.dWgs84_x = value["result"][nPos]["wgs84_x"].asDouble();//stru.dWgs84_y = value["result"][nPos]["wgs84_y"].asDouble();//stru.dMars_x = value["result"][nPos]["mars_x"].asDouble();//stru.dMars_y = value["result"][nPos]["mars_y"].asDouble();//lstCardDevData.emplace_back(stru);}} }// 解析URL地址 [3/14/2017/shike] void CWininetHttp::ParseURLWeb( std::string strUrl, std::string& strHostName, std::string& strPageName, WORD& sPort) {sPort = 80;string strTemp(strUrl);std::size_t nPos = strTemp.find("http://");if (nPos != std::string::npos){strTemp = strTemp.substr(nPos + 7, strTemp.size() - nPos - 7);}nPos = strTemp.find('/');if ( nPos == std::string::npos ) //沒有找到{strHostName = strTemp;}else{strHostName = strTemp.substr(0, nPos);}std::size_t nPos1 = strHostName.find(':');if ( nPos1 != std::string::npos ){std::string strPort = strTemp.substr(nPos1 + 1, strHostName.size() - nPos1 - 1);strHostName = strHostName.substr(0, nPos1);sPort = (WORD)atoi(strPort.c_str());}if ( nPos == std::string::npos ){return ;}strPageName = strTemp.substr(nPos, strTemp.size() - nPos); }// 關閉句柄 [3/14/2017/shike] void CWininetHttp::Release() {ReleaseHandle(m_hRequest); ReleaseHandle(m_hConnect); ReleaseHandle(m_hSession); }// 釋放句柄 [3/14/2017/shike] void CWininetHttp::ReleaseHandle( HINTERNET& hInternet ) {if (hInternet) { InternetCloseHandle(hInternet); hInternet = NULL; } }// UTF-8轉為GBK2312 [3/14/2017/shike] char* CWininetHttp::UtfToGbk(const char* utf8) {int len = MultiByteToWideChar(CP_UTF8, 0, utf8, -1, NULL, 0);wchar_t* wstr = new wchar_t[len+1];memset(wstr, 0, len+1);MultiByteToWideChar(CP_UTF8, 0, utf8, -1, wstr, len);len = WideCharToMultiByte(CP_ACP, 0, wstr, -1, NULL, 0, NULL, NULL);char* str = new char[len+1];memset(str, 0, len+1);WideCharToMultiByte(CP_ACP, 0, wstr, -1, str, len, NULL, NULL);if(wstr) delete[] wstr;return str; }

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