解决Windows下json.hpp中文乱码问题
文中使用的是 json 库,整个库的代码由一个单独的头文件json.hpp组成,用普通的C++11编写的。它没有库,没有子项目,没有依赖关系,没有复杂的构建系统,使用起来很方便。
先引用头文件和命名空间:
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <Windows.h>
#include "json.hpp"
using namespace std;
using namespace nlohmann;
json.hpp默认使用UTF8编码,在有中文情况下直接读取string会乱码,需要提供UTF8和string互相转换的函数:
std::string UTF8_To_string(const std::string& str)
{
int nwLen = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), -1, NULL, 0);
wchar_t* pwBuf = new wchar_t[nwLen + 1];//加1用于截断字符串
memset(pwBuf, 0, nwLen * 2 + 2);
MultiByteToWideChar(CP_UTF8, 0, str.c_str(), str.length(), pwBuf, nwLen);
int nLen = WideCharToMultiByte(CP_ACP, 0, pwBuf, -1, NULL, NULL, NULL, NULL);
char* pBuf = new char[nLen + 1];
memset(pBuf, 0, nLen + 1);
WideCharToMultiByte(CP_ACP, 0, pwBuf, nwLen, pBuf, nLen, NULL, NULL);
std::string retStr = pBuf;
delete[]pBuf;
delete[]pwBuf;
pBuf = NULL;
pwBuf = NULL;
return retStr;
}
std::string string_To_UTF8(const std::string& str)
{
int nwLen = ::MultiByteToWideChar(CP_ACP, 0, str.c_str(), -1, NULL, 0);
wchar_t* pwBuf = new wchar_t[nwLen + 1];//加1用于截断字符串
ZeroMemory(pwBuf, nwLen * 2 + 2);
::MultiByteToWideChar(CP_ACP, 0, str.c_str(), str.length(), pwBuf, nwLen);
int nLen = ::WideCharToMultiByte(CP_UTF8, 0, pwBuf, -1, NULL, NULL, NULL, NULL);
char* pBuf = new char[nLen + 1];
ZeroMemory(pBuf, nLen + 1);
::WideCharToMultiByte(CP_UTF8, 0, pwBuf, nwLen, pBuf, nLen, NULL, NULL);
std::string retStr(pBuf);
delete[]pwBuf;
delete[]pBuf;
pwBuf = NULL;
pBuf = NULL;
return retStr;
}
先定义一个file.json文件如下:
{
"pi": 3.141,
"happy": true,
"name": "Niels中文",
"nothing": null,
"answer": {
"everything": 42
},
"list": [1, 0, 2],
"object": {
"currency": "USD",
"value": 42.99
}
}
修改其中的name字段并保存,代码如下:
int main()
{
// read a JSON file
std::ifstream iStream("file.json");
json jsonObj;
iStream >> jsonObj;
string strName = jsonObj["name"];
string str = UTF8_To_string(strName);
str = str + "测试";
jsonObj["name"] = string_To_UTF8(str);
// write prettified JSON to another file
std::ofstream oStream("pretty.json");
oStream << std::setw(4) << jsonObj << std::endl;
return 0;
}
最后生成的pretty.json如下:
{
"answer": {
"everything": 42
},
"happy": true,
"list": [
1,
0,
2
],
"name": "Niels中文测试",
"nothing": null,
"object": {
"currency": "USD",
"value": 42.99
},
"pi": 3.141
}