c++讀取配置文件工具

//
// Created by root on 2020/5/29.
//

#ifndef READCONFIG_RRCONFIG_H
#define READCONFIG_RRCONFIG_H
#include <string>
#include <map>
namespace zkst
{
    class RrConfig
    {
    public:
        RrConfig()
        {
        }
        ~RrConfig()
        {
        }
        bool ReadConfig(const std::string & filename);
        std::string ReadString(const char* section, const char* item, const char* default_value);
        int ReadInt(const char* section, const char* item, const int& default_value);
        float ReadFloat(const char* section, const char* item, const float& default_value);
    private:
        bool IsSpace(char c);
        bool IsCommentChar(char c);
        void Trim(std::string & str);
        bool AnalyseLine(const std::string & line, std::string& section, std::string & key, std::string & value);

    private:
        //std::map<std::string, std::string> settings_;
        std::map<std::string, std::map<std::string, std::string> >settings_;
    };
}

#endif //READCONFIG_RRCONFIG_H

//
// Created by root on 2020/5/29.
//

#include "RrConfig.h"
#include <fstream>
#include <stdlib.h>

namespace zkst
{

    bool RrConfig::IsSpace(char c)
    {
        if (' ' == c || '\t' == c)
            return true;
        return false;
    }

    bool RrConfig::IsCommentChar(char c)
    {
        switch (c) {
            case '#':
                return true;
            default:
                return false;
        }
    }

    void RrConfig::Trim(std::string & str)
    {
        if (str.empty())
        {
            return;
        }
        int i, start_pos, end_pos;
        for (i = 0; i < str.size(); ++i) {
            if (!IsSpace(str[i])) {
                break;
            }
        }
        if (i == str.size())
        {
            str = "";
            return;
        }
        start_pos = i;
        for (i = str.size() - 1; i >= 0; --i) {
            if (!IsSpace(str[i])) {
                break;
            }
        }
        end_pos = i;
        str = str.substr(start_pos, end_pos - start_pos + 1);
    }

    bool RrConfig::AnalyseLine(const std::string & line, std::string& section, std::string & key, std::string & value)
    {
        if (line.empty())
            return false;
        int start_pos = 0, end_pos = line.size() - 1, pos, s_startpos, s_endpos;
        if ((pos = line.find("#")) != -1)
        {
            if (0 == pos)
            {
                return false;
            }
            end_pos = pos - 1;
        }
        if (((s_startpos = line.find("[")) != -1) && ((s_endpos = line.find("]"))) != -1)
        {
            section = line.substr(s_startpos+1, s_endpos -1);
            return true;
        }
        std::string new_line = line.substr(start_pos, start_pos + 1 - end_pos);
        if ((pos = new_line.find('=')) == -1)
            return false;
        key = new_line.substr(0, pos);
        value = new_line.substr(pos + 1, end_pos + 1 - (pos + 1));
        Trim(key);
        if (key.empty()) {
            return false;
        }
        Trim(value);
        if ((pos = value.find("\r")) > 0)
        {
            value.replace(pos, 1, "");
        }
        if ((pos = value.find("\n")) > 0)
        {
            value.replace(pos, 1, "");
        }
        return true;
    }

    bool RrConfig::ReadConfig(const std::string & filename)
    {
        settings_.clear();
        std::ifstream infile(filename.c_str());
        if (!infile) {
            return false;
        }
        std::string line, key, value, section;
        std::map<std::string, std::string> k_v;
        std::map<std::string, std::map<std::string, std::string> >::iterator it;
        while (getline(infile, line))
        {
            if (AnalyseLine(line, section, key, value))
            {
                it = settings_.find(section);
                if (it != settings_.end())
                {
                    k_v[key] = value;
                    it->second = k_v;
                }
                else
                {
                    k_v.clear();
                    settings_.insert(std::make_pair(section, k_v));
                }
            }
            key.clear();
            value.clear();
        }
        infile.close();
        return true;
    }

    std::string RrConfig::ReadString(const char* section, const char* item, const char* default_value)
    {
        std::string tmp_s(section);
        std::string tmp_i(item);
        std::string def(default_value);
        std::map<std::string, std::string> k_v;
        std::map<std::string, std::string>::iterator it_item;
        std::map<std::string, std::map<std::string, std::string> >::iterator it;
        it = settings_.find(tmp_s);
        if (it == settings_.end())
        {
            return def;
        }
        k_v = it->second;
        it_item = k_v.find(tmp_i);
        if (it_item == k_v.end())
        {
            return def;
        }
        return it_item->second;
    }

    int RrConfig::ReadInt(const char* section, const char* item, const int& default_value)
    {
        std::string tmp_s(section);
        std::string tmp_i(item);
        std::map<std::string, std::string> k_v;
        std::map<std::string, std::string>::iterator it_item;
        std::map<std::string, std::map<std::string, std::string> >::iterator it;
        it = settings_.find(tmp_s);
        if (it == settings_.end())
        {
            return default_value;
        }
        k_v = it->second;
        it_item = k_v.find(tmp_i);
        if (it_item == k_v.end())
        {
            return default_value;
        }
        return atoi(it_item->second.c_str());
    }

    float RrConfig::ReadFloat(const char* section, const char* item, const float& default_value)
    {
        std::string tmp_s(section);
        std::string tmp_i(item);
        std::map<std::string, std::string> k_v;
        std::map<std::string, std::string>::iterator it_item;
        std::map<std::string, std::map<std::string, std::string> >::iterator it;
        it = settings_.find(tmp_s);
        if (it == settings_.end())
        {
            return default_value;
        }
        k_v = it->second;
        it_item = k_v.find(tmp_i);
        if (it_item == k_v.end())
        {
            return default_value;
        }
        return atof(it_item->second.c_str());
    }
}

測試

#include <iostream>
#include "RrConfig.h"

int main() {

    zkst::RrConfig config;
    config.ReadConfig("../config.ini");
    std::string HostName = config.ReadString("MYSQL", "HostName", "");
    int Port = config.ReadInt("MYSQL", "Port", 0);
    std::string UserName = config.ReadString("MYSQL", "UserName", "");
    std::string KafKa_HostName = config.ReadString("KafKa", "HostName", "");

    std::cout << "HostName=" << HostName << std::endl;
    std::cout << "Port=" << Port << std::endl;
    std::cout << "UserName=" << UserName << std::endl;
    std::cout << "KafKa_HostName=" << KafKa_HostName << std::endl;

    return 0;
}

配置文件
[MYSQL]
HostName=127.0.0.1
Port=3306
UserName=root
[KafKa]
HostName=192.168.3.26

備註：如果你在運行時找不到這個文件可以先寫成絕對路徑