linux 上编写一个Log库

因为上课的缘故，老师让我们用c++编一个log库，有以下要求

A、日志的输出格式为：[2013-04-17 12:23:17] [DEBUG] file no find

B、日志文件在超过1K大小后，自动新建一个日志文件。

C、当日志文件超过10个后，自动从第一个日志文件重新记录。

java用惯了，c++就是麻烦啊。闲来无事发到网上吧，说不定谁会有用呢

先是得到时间的头文件

/* * getTime.h * *  Created on: 2013-4-25 *      Author: sun */#if !defined(IOSTREAM_INCLUDED)#include <iostream>#endif#if !defined(TIME_H_INCLUDED)#include <time.h>#endif#if !defined(STRING_INCLUDED)#include <string>#endif#if !defined(SSTREAM_INCLUDED)#include <sstream>#endifusing namespace std;string getTime() {time_t timep;struct tm *p_tm;timep = time(NULL);p_tm = localtime(&timep); /*获取本地时区时间*/string str;ostringstream os;os<<'['<<p_tm->tm_year+1900<<'-'<<p_tm->tm_mon+1<<'-'<<p_tm->tm_mday<<' '<<p_tm->tm_hour<<':'<<p_tm->tm_min<<':'<<p_tm->tm_sec<<']';return os.str();}

这是主要的MyLog类，因为没有牵涉到具体的程序，所以还不是很完整，不过上面的要求是达到了的

/* * Log.h * *  Created on: 2013-4-25 *      Author: sun */#if !defined(GETTIME_H_INCLUDED)#include "getTime.h"#endif#if !defined(FSTREAM_INCLUDED)#include <fstream>#endifusing namespace std;class MyLog {private:string filepath;int disp_level;int lognumber;bool clear;public:void writeLog(int level, string str);MyLog(int disp_level, string filepath, int lognumber);};MyLog::MyLog(int disp_level, string filepath, int lognumber) {this->disp_level = disp_level;this->filepath = filepath;this->lognumber = lognumber;this->clear = false;}void MyLog::writeLog(int level, string str) {//判断，若level小鱼disp_level，则不予输出if (level < disp_level) {return;}//生成输出日志的stringostringstream os;os<<getTime()<<" [DEBUG] "<<str;string ostr = os.str();fstream ioFile;string temp = filepath;//判断，若clear＝false，则照常打开日志文件，从末尾开始添加，若clear＝true，则清空文件，从头开始添加if(!clear) {ioFile.open(temp.append(1,'0'+lognumber).c_str(),ios::out|ios::app);}else {ioFile.open(temp.append(1,'0'+lognumber).c_str(),ios::out|ios::trunc);clear = false;}//判断，如果文件读取失败则报错！if(!ioFile) {cout<<"open error!"<<endl;return;}//读取文件指针的位置,从而得到文件大小streampos ps = ioFile.tellg();cout << "File size: " << ps << endl;//判断如果文件大小大于1024即1K，那么就将log编号加1，如果大于9则回到0，且每次变化后都使clear＝trueif(ps > 1024) {lognumber++;if (lognumber > 9) {lognumber = 0;}clear = true;//重新调用writeLog函数，且将原来的fstream关闭writeLog(level, str);ioFile.close();return;}//将日志写入日志文件ioFile<<ostr<<endl;ioFile.close();cout<<"write \""<<ostr<<"\" to \""<<temp<<"\""<<endl;}

最后写个主函数测试一下

/* * main.cpp * *  Created on: 2013-4-25 *      Author: sun */#include "MyLog.h"using namespace std;int main(void) {MyLog* mylog = new MyLog(1,"/home/sun/log",0);int i;for(i=0;i<11;i++) {mylog->writeLog(1,"my log!");}delete(mylog);return 0;}

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