利用jsoncpp来做json的解析。
1.jsoncpp下载
从 下载jsoncpp。makefiles目录下面有VS的工程。
2.写到string
string test_write(){ Json::Value root; // 表示整个 json 对象 root["platenumber"] = Json::Value("value_string"); root["platetype"] = Json::Value(0); root["snopshotplaceid"] = Json::Value("12345678"); root["snopshottime"] = Json::Value("20171222"); root["platenumber"] = Json::Value("123456"); root["imgpath"] = Json::Value("D:/TEST.JPG"); root["extFlag"] = Json::Value("EXTFLAG"); root["taskid"] = Json::Value("TASKID"); Json::ValueType type = root.type(); // 获得 root 的类型，此处为 objectValue 类型。 Json::StyledWriter styled_writer; string strJson = GBKToUTF8(styled_writer.write(root)); const char* chData = strJson.c_str(); cout << strJson << endl; return strJson;} 其中多字节下，GBK转UTF8
string GBKToUTF8(const std::string& strGBK){ string strOutUTF8 = ""; WCHAR * str1; int n = MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, NULL, 0); str1 = new WCHAR[n]; MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, str1, n); n = WideCharToMultiByte(CP_UTF8, 0, str1, -1, NULL, 0, NULL, NULL); char * str2 = new char[n]; WideCharToMultiByte(CP_UTF8, 0, str1, -1, str2, n, NULL, NULL); strOutUTF8 = str2; delete[]str1; str1 = NULL; delete[]str2; str2 = NULL; return strOutUTF8;}
2.从string解析json
void test_read(string str){ string str_json = Utf8ToGbk(str.c_str()); Json::Reader reader; Json::Value root; if (reader.parse(str_json, root)) // reader将Json字符串解析到root，root将包含Json里所有子元素 { std::cout << "========================[Dispatch]========================" << std::endl; std::string plate_number = root["platenumber"].asString(); int plate_type = root["platetype"].asInt(); std::string snopshot_place_id = root["snopshotplaceid"].asString(); std::string snopshot_time = root["snopshottime"].asString(); std::string image_path = root["imgpath"].asString(); std::string extFlag = root["extFlag"].asString(); std::string taskid = root["taskid"].asString(); cout << "plate_number :" << plate_number << endl; cout << "plate_type :" << plate_type << endl; cout << "snopshot_place_id :" << snopshot_place_id << endl; cout << "snopshot_time :" << snopshot_time << endl; cout << "image_path :" << image_path << endl; cout << "extFlag :" << extFlag << endl; cout << "taskid :" << taskid << endl; cout << endl; }} 其中，多字节下UTF8转GBK
std::string Utf8ToGbk(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;}
3.完整示例
// mytest.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include#include #include "..\\..\\include\\json\\writer.h" //json解析#include "..\\..\\include\\json\\reader.h" //json解析#ifdef _DEBUG#pragma comment(lib, "..\\..\\build\\vs71\\debug\\lib_json\\json_vc71_libmtd.lib")#else#pragma comment(lib, "..\\..\\build\\vs71\\release\\lib_json\\json_vc71_libmt.lib")#endifusing namespace std;string GBKToUTF8(const std::string& strGBK){ string strOutUTF8 = ""; WCHAR * str1; int n = MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, NULL, 0); str1 = new WCHAR[n]; MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, str1, n); n = WideCharToMultiByte(CP_UTF8, 0, str1, -1, NULL, 0, NULL, NULL); char * str2 = new char[n]; WideCharToMultiByte(CP_UTF8, 0, str1, -1, str2, n, NULL, NULL); strOutUTF8 = str2; delete[]str1; str1 = NULL; delete[]str2; str2 = NULL; return strOutUTF8;}std::string Utf8ToGbk(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;}string test_write(){ Json::Value root; // 表示整个 json 对象 root["platenumber"] = Json::Value("value_string"); root["platetype"] = Json::Value(0); root["snopshotplaceid"] = Json::Value("12345678"); root["snopshottime"] = Json::Value("20171222"); root["platenumber"] = Json::Value("123456"); root["imgpath"] = Json::Value("D:/TEST.JPG"); root["extFlag"] = Json::Value("EXTFLAG"); root["taskid"] = Json::Value("TASKID"); Json::ValueType type = root.type(); // 获得 root 的类型，此处为 objectValue 类型。 Json::StyledWriter styled_writer; string strJson = GBKToUTF8(styled_writer.write(root)); const char* chData = strJson.c_str(); cout << strJson << endl; return strJson;}void test_read(string str){ string str_json = Utf8ToGbk(str.c_str()); Json::Reader reader; Json::Value root; if (reader.parse(str_json, root)) // reader将Json字符串解析到root，root将包含Json里所有子元素 { std::cout << "========================[Dispatch]========================" << std::endl; std::string plate_number = root["platenumber"].asString(); int plate_type = root["platetype"].asInt(); std::string snopshot_place_id = root["snopshotplaceid"].asString(); std::string snopshot_time = root["snopshottime"].asString(); std::string image_path = root["imgpath"].asString(); std::string extFlag = root["extFlag"].asString(); std::string taskid = root["taskid"].asString(); cout << "plate_number :" << plate_number << endl; cout << "plate_type :" << plate_type << endl; cout << "snopshot_place_id :" << snopshot_place_id << endl; cout << "snopshot_time :" << snopshot_time << endl; cout << "image_path :" << image_path << endl; cout << "extFlag :" << extFlag << endl; cout << "taskid :" << taskid << endl; cout << endl; }}int _tmain(int argc, _TCHAR* argv[]){ string strJson = test_write(); test_read(strJson); system("pause"); return 0;}
运行结果：
完整工程代码：
测试代码在makefiles目录下的mytest，工程基于VS2013