C++读取配置文件代码

lehoon 07-06 3436

前言：

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介绍

在一般项目中经常会用到配置文件配置一些系统参数，比如网关的端口号、memcache、redis等配置参数，数据库的ip地址、端口号、用户名密码等。在java中有properties文件读取类。 c++中有ini的读取实现，注册表的读取实现，普通文件读取等实现，我们项目中使用的类似ini配置文件，支持分区配置参数。

配置文件如下：

实现

代码实现如下：

configure.h

#ifndef GW_CONFIGURE_H_#define GW_CONFIGURE_H_#include <string>#include <map>#include <stdint.h>#include "base/basic_types.h"namespace gateway {class Configure { public:	Configure();	~Configure();		int Init(const std::string& file);	std::string GetValueAsString(const std::string& group,								 const std::string& key,								 const std::string& default_value) const;	uint32_t GetValueAsUint32(const std::string& group,							const std::string& key,							uint32_t default_value) const;	double GetValueAsDouble(const std::string& group,							const std::string& key,							double default_value) const;	bool GetValueAsBool(const std::string& group,						  const std::string& key,						  bool  default_value) const; private:	 private:	std::map<std::string, std::map<std::string, std::string> > items_;	DISALLOW_COPY_AND_ASSIGN(Configure);};} // namespace gateway#endif // GW_CONFIGURE_H_

configure.h代码

configure.cpp代码如下：

#include <stdio.h>#include <stdlib.h>#include <iostream>#include "gateway/configure.h"namespace gateway {class ConfigFile {public:	ConfigFile();	~ConfigFile();	int Init(const char* file);	int ParseFile(std::map<std::string, std::map<std::string, std::string> >& group_items);private:	int GetLine(std::string& line);	int GetKeyAndValue(const std::string& line, std::string& key, std::string& value);	void Trim(std::string& str);private:	FILE* pf_;	enum {		kErrorRow    = 0,		kEmptyRow,		kGroupRow,		kValueRow,	};	DISALLOW_COPY_AND_ASSIGN(ConfigFile);};ConfigFile::ConfigFile() : pf_(NULL) {}ConfigFile::~ConfigFile() {	if (pf_ != NULL) {		fclose(pf_);	}}int ConfigFile::Init(const char* file) {	pf_ = fopen(file, "r");	if (pf_ == NULL) return RESULT_ERROR;	return RESULT_OK;}void ConfigFile::Trim(std::string& str) {	size_t size = str.size();	if (size == 0) return ;	size_t begin = 0;	while (begin < size && str[begin] == ' ') begin++;	size_t end = size - 1;	while (end > begin && str[end] == ' ') end--;	if (end >= begin) {		str = str.substr(begin, end + 1 - begin);	} else {		str = "";	}}int ConfigFile::GetLine(std::string& line) {	const int kLen = 512;	char buf[kLen] = {0};	if (fgets(buf, kLen, pf_) != NULL) {		line = buf;		Trim(line);		if (line.length() < 2) return kEmptyRow;		if (line[0] == '#') return kEmptyRow;				std::string s = line.substr(line.length() - 2);		if (s == "\n\r") {			line = line.substr(0, line.length() - 2);		}		s = line.substr(line.length() - 1);		if (s == "\r" || s == "\n") {			line = line.substr(0, line.length() - 1);		}		if (line.length() == 0) return kEmptyRow;		if ((line[0] == '[') && (line[line.length() - 1] == ']')) {			line = line.substr(1, line.length() - 2);			return kGroupRow;		}		return kValueRow;	}	//包括	return kErrorRow;}int ConfigFile::GetKeyAndValue(const std::string& line, std::string& key, std::string& value) {	int pos = line.find_first_of("=");	if (pos < 0) return RESULT_ERROR;	key = line.substr(0, pos);	Trim(key);	value = line.substr(pos + 1);	Trim(value);	return RESULT_OK;}int ConfigFile::ParseFile(std::map<std::string, std::map<std::string, std::string> >& group_items) {	fseek(pf_, 0, SEEK_SET);	int type = kErrorRow;	std::string line;		std::string group;	std::string key;	std::string value;	while ((type = GetLine(line)) != kErrorRow) {		//处理行		if (type == kGroupRow) {			group = line;			group_items[group] = std::map<std::string, std::string>();		} else if (type == kValueRow){			//找到key and value			if (GetKeyAndValue(line, key, value) == RESULT_OK) {				group_items[group][key] = value;			}		}	}	return RESULT_OK;}//=============================Configure::Configure() {}	Configure::~Configure() {}	int Configure::Init(const std::string& file) {	ConfigFile config;	int result = config.Init(file.c_str());	if (result != RESULT_OK) return result;	//解析具体配置文件:	result = config.ParseFile(items_);	return result;}std::string Configure::GetValueAsString(const std::string& group,																				const std::string& key,																				const std::string& default_value) const {	std::string result = default_value;	std::map<std::string, std::map<std::string, std::string> >::const_iterator g_it = items_.find(group);	if (g_it != items_.end()) {		std::map<std::string, std::string>::const_iterator it = g_it->second.find(key);		if (it != g_it->second.end()) {			result = it->second;		}	}	return result;}	uint32_t Configure::GetValueAsUint32(const std::string& group,																	 const std::string& key,																	 uint32_t default_value) const {	uint32_t result = default_value;	std::map<std::string, std::map<std::string, std::string> >::const_iterator g_it = items_.find(group);	if (g_it != items_.end()) {		std::map<std::string, std::string>::const_iterator it = g_it->second.find(key);		if (it != g_it->second.end()) {			result = atoi(it->second.c_str());		}	}	return result;}	double Configure::GetValueAsDouble(const std::string& group,																	 const std::string& key,																	 double default_value) const {	double result = default_value;	std::map<std::string, std::map<std::string, std::string> >::const_iterator g_it = items_.find(group);	if (g_it != items_.end()) {		std::map<std::string, std::string>::const_iterator it = g_it->second.find(key);		if (it != g_it->second.end()) {			result = atof(it->second.c_str());		}	}	return result;}	bool Configure::GetValueAsBool(const std::string& group,															 const std::string& key,															 bool  default_value) const {	bool result = default_value;	std::map<std::string, std::map<std::string, std::string> >::const_iterator g_it = items_.find(group);	if (g_it != items_.end()) {		std::map<std::string, std::string>::const_iterator it = g_it->second.find(key);		if (it != g_it->second.end()) {			result = (it->second == "1");		}	}	return result;}} // namespace gateway

案例

使用样例如下：

int gw_set_opt(gateway::Gateway::Options& options, const std::string& file) {	gateway::Configure config;	if (config.Init(file) != RESULT_OK) {		return RESULT_ERROR;	}	options.unit_io_nevents = config.GetValueAsUint32("unit", "io_nevents", options.unit_io_nevents);	options.unit_reactor_timeout = config.GetValueAsUint32("unit", "reactor_timeout", options.unit_reactor_timeout); 	options.unit_timer_nevents = 0;	options.unit_conn_timeout = config.GetValueAsUint32("unit", "conn_timeout", options.unit_conn_timeout);	options.unit_listen_addr = config.GetValueAsString("unit", "listen_addr", options.unit_listen_addr);

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