【C++】手搓读写properties文件源码
- 参考文章
思路
properties文件实际上就是键值对的一种形式，用等号连接键和值。c++中和键值对最贴切的就是STL中的map了。所以我使用map作为properties的实际内存存储，同时为了方便使用，另外多一个set类型的字段记录所有的key。大致流程为：
1、逐行扫描文件内容；
2、过滤注释（#后面的为注释）；
3、根据等号切割key和value；
4、保存key和value到map中；
需求：
1、当key没有值时：可以设定个默认值
2、读取文件时只有KEY没哟默认值会报错，添加一个默认值给该KEY
3、修改KEY的值时并保存到文件中
properties.h 头文件
/********************************************************************************* @file : properties.h* @author : CircleDBA* @mail : weiyuanquan@kingbase.com.cn* @blog : circle-dba.blog.csdn.net* @date : 24-5-8*******************************************************************************/#ifndef KINGBASEMANAGERTOOLS_PROPERTIES_H
#define KINGBASEMANAGERTOOLS_PROPERTIES_H#include <iostream>
#include <fstream>
#include <map>
#include <string>
#include <algorithm>
#include <sstream>
#include <vector>
#include <set>
#include <filesystem>using namespace std;namespace Circle {class properties {private:string config_path;map<string, string>* props = nullptr;set<string>* keys = nullptr;void trim(string& s);vector<string> split(const string& str, char pattern);public:properties();virtual ~properties();void file(boost::filesystem::path path);bool is_exists();bool load(std::string defaultValue);bool load(){load("None");};set<string>* getKeys() const;map<string, string>* getProps() const;string getValue(const string& key,const string& defaultValue);bool setValue(const string& key,const string& Value);};} // Circle#endif //KINGBASEMANAGERTOOLS_PROPERTIES_Hproperties.cpp 文件
/********************************************************************************* @file : properties.cpp* @author : CircleDBA* @mail : weiyuanquan@kingbase.com.cn* @blog : circle-dba.blog.csdn.net* @date : 24-5-8*******************************************************************************/#include "properties.h"namespace fs = std::filesystem;Circle::properties::properties() {this->props = new map<string, string>();this->keys = new set<string>();
}Circle::properties::~properties() {delete props;delete keys;}
//设置配置文件路径
void Circle::properties::file(std::string path){this->config_path = path;
}
//判断配置文件是否存在
bool Circle::properties::is_exists(){return fs::exists(this->config_path);
}void Circle::properties::trim(string& s)
{if (!s.empty()){s.erase(0, s.find_first_not_of(" "));s.erase(s.find_last_not_of(" ") + 1);}}vector<string> Circle::properties::split(const string& str, char pattern)
{vector<string> res;stringstream input(str);string temp;while (getline(input, temp, pattern)){res.push_back(temp);}return res;
}bool Circle::properties::load(std::string defaultValue = "None"){std::ifstream file(this->config_path);std::string line;while (getline(file, line)) {trim(line);//去空行if (line.empty() || line == "\r" || line[0] == '#'){continue;}//处理等号后为空的配置vector<string> res = split(line, '=');if (res.size() < 2){res[1] = defaultValue;}int t = res[1].find("#");if (t != string::npos) {res[1].erase(t);}for_each(res.begin(), res.end(), [=](string& s)mutable {trim(s);});props->insert(make_pair(res[0], res[1]));keys->insert(res[0]);}file.close();
}set<string>* Circle::properties::getKeys() const {return keys;
}map<string, string>* Circle::properties::getProps() const {return this->props;
}string Circle::properties::getValue(const string& key,const string& defaultValue) {if (props->find(key) == props->end()){return defaultValue;}string value =this->props->at(key);return value;
}bool Circle::properties::setValue(const string& key,const string& Value) {if (props->find(key) == props->end()){this->props->insert(make_pair(key, Value));}else{props->at(key) = Value;}std::ofstream outFile(this->config_path);for (const auto& pair : *props) {outFile << pair.first << " = " << pair.second << std::endl;}return true;
}
example.properties 示例代码
key1 = value1
key3 = value3
key5 = aaa
log.key4 = value4运行例子：
#include "properties.h"
main(){std::string configPaht = "example.properties"Circle::properties properties;properties.file(configPaht);//判断配置文件是否存在if(properties.is_exists()){//读取配置文件写入props，keysproperties.load();//读取键值，如果不存在就返回默认值defaultValueproperties.getValue("key5","defaultValue");//设置键值并写入文件properties.setValue("key5","aaa");}
}
参考文章
C++读取Properties的工具类
