C++学习之路： 时间戳 封装成类

 1 #ifndef TIMESTAMP_H
 2 #define TIMESTAMP_H 
 3 
 4 #include <string>
 5 #ifndef __STDC_FORMAT_MACROS
 6 #define __STDC_FORMAT_MACROS
 7 #endif /* __STDC_FORMAT_MACROS */
 8 #include <inttypes.h>
 9 
10 class Timestamp
11 {
12 public:
13     Timestamp();
14     Timestamp(int64_t value);
15 
16     bool isValid() const
17     { return value_ > 0; }
18 
19     std::string toString() const;
20     std::string toFormatString() const;  
21 
22     static Timestamp now();           //获取时间戳
23 
24 private:
25     int64_t value_; //微秒级别的时间戳
26 };
27 
28 
29 #endif  /*TIMESTAMP_H*/

 1 #include "Timestamp.h"
 2 #include <time.h>
 3 #include <sys/time.h>
 4 #include <stdio.h>
 5 #include <string.h>
 6 using namespace std;
 7 
 8 
 9 Timestamp::Timestamp()
10     :value_(0)
11 {
12 
13 }
14 
15 Timestamp::Timestamp(int64_t value)
16     :value_(value)
17 {
18 
19 }
20 
21 string Timestamp::toString() const
22 {
23     //1411373695.488096
24     int64_t sec = value_ / (1000 * 1000);
25     int64_t usec = value_ % (1000 * 1000);
26     // %06lld
27     char text[32] = {0};
28     snprintf(text, sizeof text, "%lld.%06lld", sec, usec);
29 
30     return string(text);
31 }
32 
33 string Timestamp::toFormatString() const
34 {
35     //20140922 08:14:55.488096
36     time_t sec = value_ / (1000 * 1000);
37     int64_t usec = value_ % (1000 * 1000);
38     struct tm st;
39     //gmtime_r(&sec, &st);
40     localtime_r(&sec, &st);         //localtime只是把时间戳转换为我们所熟知的 2014.7.40 xx：xx：xx 的格式 并不获取时间
41 
42     char text[100] = {0};
43     snprintf(text, sizeof text, "%04d%02d%02d %02d:%02d:%02d.%06lld", st.tm_year + 1900, st.tm_mon + 1, st.tm_mday, st.tm_hour, st.tm_min
44         , st.tm_sec, usec);
45     return string(text);
46 }
47 
48 Timestamp Timestamp::now()
49 {
50     struct timeval tv;
51     memset(&tv, 0, sizeof tv);
52     gettimeofday(&tv, NULL);           //获取时间戳偏移量
53 
54     int64_t val = 0;
55     val += static_cast<int64_t>(tv.tv_sec) * 1000 * 1000;
56     val += tv.tv_usec;
57 
58     return Timestamp(val);
59 }

 1 #include "Timestamp.h"
 2 #include <iostream>
 3 using namespace std;
 4 
 5 int main(int argc, char const *argv[])
 6 {
 7     Timestamp now = Timestamp::now();
 8 
 9     cout << now.toString() << endl;
10     cout << now.toFormatString() << endl;
11     return 0;
12 }