OC -- NSCalendar的使用 与OC的反射

NSDate *date = [NSDate date];

NSLog(@"%@", date);

NSCalendar *ca = [NSCalendar currentCalendar];

NSDateComponents *res = [ca components:NSCalendarUnitYear fromDate:date];

NSLog(@"%ld", res.year);

NSDateComponents *res2 = [ca components:NSCalendarUnitMonth fromDate:date];

NSLog(@"%ld", res2.month);

NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;

NSDateComponents *res3 = [ca components:unit fromDate:date];

NSLog(@"%ld--%ld--%ld", res3.year, res3.month, res3.day);

NSLog(@"%ld:%ld:%ld", res3.hour, res3.minute, res3.second);

// 反射reflect

NSString *str = @"Person";

Class class = NSClassFromString(str);

Person *p = [[class alloc] init];

NSLog(@"%@", [p class]);

NSString *str2 = NSStringFromClass([p class]);

NSLog(@"%@", str2);

// 方法的反射

NSString *method = @"say";

SEL sel = NSSelectorFromString(method);

[p performSelector:sel];