c++ - Boost Property Tree Json 读取包含 LPWSTR 的文件

Question

我有一些代码应该使用 WriteFile 将内容写入文件。写入文件的内容类型为LPWSTR即wchar_t *。该文件将写入ip、ssl 和compression。考虑以下代码:

#include <Windows.h>
#include <iostream>
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
int main()
{
    LPWSTR ip = NULL;
    LPWSTR ssl = NULL;
    LPWSTR comp = NULL;
    wchar_t buffer[300];
    HANDLE hFile;
    BOOL bErrorFlag;
    DWORD dwBytesToWrite = 0; //(DWORD)strlen(buffer);
    DWORD dwBytesWritten = 0;

    if(ip == NULL  || wcslen(ip) == 0 )
    {
        ip = L"127.0.0.1";
    }

    if(ssl == NULL || wcslen(ssl) == 0)
    {
        ssl = L"False";
    }

    if(comp == NULL || wcslen(comp) == 0 )
    {
        comp = L"True";
    }


    wsprintf(buffer, L"{\n\"ip\": \"%ls\",\n\"ssl\": \"%ls\",\n\"compression\":\"%ls\"\n}",ip,ssl,comp);
    //swprintf(buffer, 150, L"{\n\"ipaddress\": \"%ls\",\n\"ssl\": \"%ls\",\n\"compression\":\"%ls\"\n}",ip,ssl,comp);
    std::wcout << buffer << std::endl;
    dwBytesToWrite = (wcslen(buffer)) * sizeof(wchar_t);

    hFile = CreateFile(L"C://SomeFolder//some_config.config",                // name of the write
                       GENERIC_WRITE,          // open for writing
                       0,                      // do not share
                       NULL,                   // default security
                       CREATE_ALWAYS,             // always create new file
                       FILE_ATTRIBUTE_NORMAL,  // normal file
                       NULL);

     bErrorFlag = WriteFile( 
                    hFile,           // open file handle
                    buffer,      // start of data to write
                    dwBytesToWrite,  // number of bytes to write
                    &dwBytesWritten, // number of bytes that were written
                    NULL);            // no overlapped structure

      CloseHandle(hFile);
      boost::property_tree::ptree pt;
      try
      {
          boost::property_tree::read_json("C://SomeFolder//some_config.config", pt);
      }
      catch(std::exception &e)
      {
          std::cout << e.what();
      }
      try
      {
          std::cout << pt.get<std::string>("ip");
      }
      catch(std::exception &e)
      {
          std::cout << e.what();
      }
}

文件内容会有

{
"ip": "127.0.0.1",
"ssl": "False",
"compression":"True"
}

但是使用 read_json 失败并给出错误:

C://SomeFolder//some_config.config(1): expected object name 
No such node (ip)

代码有什么问题？为什么 read_json 不能读取写入的文件？如果我错误地使用了 WriteFile，请纠正我。谢谢。

Answer 1

你想使用wptree:

boost::property_tree::wptree pt;
boost::property_tree::read_json("C://SomeFolder//some_config.config", pt);
std::wcout << pt.get<std::wstring>(L"ip");

还要注意那里的 L"ip" 和 wstring。

旁注:如果从字符串字面量赋值，则需要 LPWSTR 指针(LPCWSTR？我猜)的 const 版本