objective c - NSDateFormatter输出不正确

Question

为什么以下代码在转换后输出错误的Date？

NSString *customDate = @"23-06-1993";
NSLog(@"Custom Date: %@", customDate);
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"dd-MM-yyyy"];
NSDate *birthDayDate = [formatter dateFromString:customDate];
NSLog(@"After Conversion: %@", birthDayDate);

输出：

Custom Date: 20-12-1993
After Conversion: 1993-12-19 16:00:00 +0000

提前致谢。

Answer 1

除非您明确设置，否则

NSDateFormatter会使用您当前的时区（GMT + 8）。您应该将格式化程序的时区设置为UTC（换句话说，GMT）以正确格式化日期。

NSLog(@"Current timezone: %@", [NSTimeZone defaultTimeZone]);

NSString *customDate = @"23-06-1993";
NSLog(@"Custom Date: %@", customDate);

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"dd-MM-yyyy"];
[formatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];

NSDate *utcDate = [formatter dateFromString:customDate];
NSLog(@"After Conversion: %@", utcDate);

---

Custom Date: 23-06-1993
After Conversion: 1993-06-23 00:00:00 +0000