NSDate和NSString之间的转换

//输入的日期字符串形如：@"1992-05-21 13:08:08"

- (NSDate *)dateFromString:(NSString *)dateString{

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setDateFormat: @"yyyy-MM-dd HH:mm:ss"]; 

NSDate *destDate= [dateFormatter dateFromString:dateString];

[dateFormatter release];

return destDate;

}

- (NSString *)stringFromDate:(NSDate *)date{

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 

//zzz表示时区，zzz可以删除，这样返回的日期字符将不包含时区信息 +0000。

[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss zzz"];

NSString *destDateString = [dateFormatter stringFromDate:date];

[dateFormatter release];

return destDateString;

}

- (IBAction)handleDidPressBtn1{

NSLog(@"%@\n", [self dateFromString:@"2011-08-09 12:02:01"]);

NSLog(@"%@\n", [self stringFromDate:[self dateFromString:@"2011-08-09 12:02:01"]]);

}

输出结果如下：

-08-09 04:02:01 +0000

-08-09 12:02:01 GMT+08:00