C++编写Config类读取配置文件
老外写的一段代码，在Server中编写这个类读取配置文件比较实用
config.txt的文件内容：
ipAddress=10.10.90.125
port=3001
username=mark
password=2d2df5a
编译运行输出:
port:3001
ipAddress:10.10.90.125
username:mark
password:2d2df5a
这个类还有很多其他的方法，可以调用试试。
//Config.h
#pragma once
#include
#include
// Config.cpp
#include "Config.h"
using namespace std;
Config::Config( string filename, string delimiter,
string comment )
: m_Delimiter(delimiter), m_Comment(comment)
{
// Construct a Config, getting keys and values from given file
std::ifstream in( filename.c_str() );
if( !in ) throw File_not_found( filename );
in >> (*this);
}
Config::Config()
: m_Delimiter( string(1,'=') ), m_Comment( string(1,'#') )
{
// Construct a Config without a file; empty
}
bool Config::KeyExists( const string& key ) const
{
// Indicate whether key is found
mapci p = m_Contents.find( key );
return ( p != m_Contents.end() );
}
/* static */
void Config::Trim( string& inout_s )
{
// Remove leading and trailing whitespace
static const char whitespace[] = " \n\t\v\r\f";
inout_s.erase( 0, inout_s.find_first_not_of(whitespace) );
inout_s.erase( inout_s.find_last_not_of(whitespace) + 1U );
}
std::ostream& operator<<( std::ostream& os, const Config& cf )
{
// Save a Config to os
for( Config::mapci p = cf.m_Contents.begin();
p != cf.m_Contents.end();
++p )
{
os << p->first << " " << cf.m_Delimiter << " ";
os << p->second << std::endl;
}
return os;
}
void Config::Remove( const string& key )
{
// Remove key and its value
m_Contents.erase( m_Contents.find( key ) );
return;
}
std::istream& operator>>( std::istream& is, Config& cf )
{
// Load a Config from is
// Read in keys and values, keeping internal whitespace
typedef string::size_type pos;
const string& delim = cf.m_Delimiter; // separator
const string& comm = cf.m_Comment; // comment
const pos skip = delim.length(); // length of separator
string nextline = ""; // might need to read ahead to see where value ends
while( is || nextline.length() > 0 )
{
// Read an entire line at a time
string line;
if( nextline.length() > 0 )
{
line = nextline; // we read ahead; use it now
nextline = "";
}
else
{
std::getline( is, line );
}
// Ignore comments
line = line.substr( 0, line.find(comm) );
// Parse the line if it contains a delimiter
pos delimPos = line.find( delim );
if( delimPos < string::npos )
{
// Extract the key
string key = line.substr( 0, delimPos );
line.replace( 0, delimPos+skip, "" );
// See if value continues on the next line
// Stop at blank line, next line with a key, end of stream,
// or end of file sentry
bool terminate = false;
while( !terminate && is )
{
std::getline( is, nextline );
terminate = true;
string nlcopy = nextline;
Config::Trim(nlcopy);
if( nlcopy == "" ) continue;
nextline = nextline.substr( 0, nextline.find(comm) );
if( nextline.find(delim) != string::npos )
continue;
nlcopy = nextline;
Config::Trim(nlcopy);
if( nlcopy != "" ) line += "\n";
line += nextline;
terminate = false;
}
// Store key and value
Config::Trim(key);
Config::Trim(line);
cf.m_Contents[key] = line; // overwrites if key is repeated
}
}
return is;
}
bool Config::FileExist(std::string filename)
{
bool exist= false;
std::ifstream in( filename.c_str() );
if( in )
exist = true;
return exist;
}
void Config::ReadFile( string filename, string delimiter,
string comment )
{
m_Delimiter = delimiter;
m_Comment = comment;
std::ifstream in( filename.c_str() );
if( !in ) throw File_not_found( filename );
in >> (*this);
}
//main.cpp
#include "Config.h"
int main()
{
int port;
std::string ipAddress;
std::string username;
std::string password;
const char ConfigFile[]= "config.txt";
Config configSettings(ConfigFile);
port = configSettings.Read("port", 0);
ipAddress = configSettings.Read("ipAddress", ipAddress);
username = configSettings.Read("username", username);
password = configSettings.Read("password", password);
std::cout<<"port:"< std::cout<<"ipAddress:"< std::cout<<"username:"< std::cout<<"password:"<
return 0;
}
config.txt的文件内容：
ipAddress=10.10.90.125
port=3001
username=mark
password=2d2df5a
编译运行输出:
port:3001
ipAddress:10.10.90.125
username:mark
password:2d2df5a
这个类还有很多其他的方法，可以调用试试。