[OC Foundation框架 - 15] NSDate

日期处理类

1. 定义
2. 时间间隔计算
3. 时间比较，返回其一
4. 时间格式化

 void dateCreate()
 {
     //date return current time
     NSDate *date = [NSDate date];
     NSLog(@"%@", date);

     //+ 10 sec
     date = [NSDate dateWithTimeIntervalSinceNow:];
     NSLog(@"%@", date);

     //1970-1-1 00:00:00 + 10 sec
     date = [NSDate dateWithTimeIntervalSince1970:];
     NSLog(@"%@", date);

     //Random future time?
     date = [NSDate distantFuture];
     NSLog(@"%@", date);

     date = [NSDate distantPast];
     NSLog(@"%@", date);
 }

 void dateUse()
 {
     NSDate *date = [NSDate date];
     //NSTimeInterval is double
     NSTimeInterval i = [date timeIntervalSince1970];
     NSLog(@"%f", i);
 }

 void dateFormat()
 {
     NSDate *date = [NSDate date];
     NSDateFormatter *f = [[NSDateFormatter alloc] init];
     f.dateFormat = @"yyyy-MMM-dd HH:mm:ss";
     NSString *s = [f stringFromDate:date];
     NSLog(@"1:%@", s);

     NSDate *d2 = [f dateFromString:@"2014-7月-29 22:12:12"];
     NSLog(@"2:%@",d2);
 }

 

字符串、日期格式转换：

         // 17.将2013年05月05日转换为2013-05-05
         NSMutableString *str17 = @"2013年05月05日";
         NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
         dateFormatter1.dateFormat = @"yyyy年MM月dd日";
         NSDate *date1 = [dateFormatter1 dateFromString:str17];
         NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc] init];
         dateFormatter2.dateFormat = @"yyyy-MM-dd";
         NSString *str17_2 = [dateFormatter2 stringFromDate:date1];
         NSLog(@"题目17, 转换后的日期是%@", str17_2);