object c NSDate

//
//  main.m
//  DateDemo
//
//  Created by 千雅爸爸 on 16/10/7.
//  Copyright ? 2016年 kodulf. All rights reserved.
//#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) {@autoreleasepool {//oc 日期操作，和java几乎是一模一样，有区别的是这里的Date是直接格林尼治时间，java直接是系统的时间。NSDate *date = [NSDate date];NSLog(@"%@",date);//格林尼治时间//如何获取往前，往后的时间date = [[NSDate alloc] initWithTimeInterval:60 sinceDate:date];NSLog(@"60 秒以后的时间%@",date);//注意这里是60秒，而不是毫秒//进行时区的转换,首先获取系统的当前的时区NSTimeZone *zone = [NSTimeZone systemTimeZone];NSInteger interval = [zone secondsFromGMT];//获取时间差NSDate *localDate = [date dateByAddingTimeInterval:interval];NSLog(@"本地时间：%@",localDate);//如何对两个日期，进行日期的比较NSDate *currentDate =[NSDate date];NSDate *laterDate = [[NSDate alloc] initWithTimeInterval:60*60 sinceDate:currentDate];NSDate *earlierDate = [[NSDate alloc] initWithTimeInterval:-60 sinceDate:currentDate];if([currentDate laterDate:laterDate]){//这个方法说的是后面的是NSLog(@"currentDate: %@日期比laterDate:%@晚",currentDate,laterDate);}if([currentDate earlierDate:earlierDate]){NSLog(@"currentDate: %@日期比earlierDate:%@早",currentDate,earlierDate);}//通过compare来比较if([currentDate compare:earlierDate] ==NSOrderedDescending){NSLog(@"晚");}//nsdate 和nsstring的比较NSDate *date1 = [NSDate date];//日期格式化对象NSDateFormatter *dateFormatter= [[NSDateFormatter alloc] init];[dateFormatter setDateFormat:@"yyyy年MM月dd HH:mm:ss zzz"];//zzz表示时区，注意标准的应该是yyyy－MM－dd HH:mm:ss zzz，这里使用年，月是为了看的清楚一些。NSString *dateString = [dateFormatter stringFromDate:date1];NSLog(@"%@",dateString);dateString = @"2016年01月01 18:18:18";dateFormatter =[[NSDateFormatter alloc] init];[dateFormatter setDateFormat:@"yyyy年MM月dd HH:mm:ss"];date1 = [dateFormatter dateFromString:dateString];NSLog(@"%@",date1);}return 0;
}