将UTC日期格式转换为本地nsdate

Question

我从我的服务器获取UTC时区的字符串日期,我需要将其转换为本地时区.

我的代码:

let utcTime = "2015-04-01T11:42:00.269Z"    
let dateFormatter = NSDateFormatter()
dateFormatter.timeZone = NSTimeZone(name: "UTC")
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
let date = dateFormatter.dateFromString(utcTime)
println("utc: \(utcTime), date: \(date)")

这个印刷品 -

utc:2015-04-01T11:42:00.269Z,日期:可选(2015-04-01 11:42:00 +0000)

如果我删除

dateFormatter.timeZone = NSTimeZone(name: "UTC") 

它打印

utc:2015-04-01T11:42:00.269Z,日期:可选(2015-04-01 08:42:00 +0000)

我的当地时区是UTC +3,在第一个选项中,我在第二个选项中得到UTC,我得到了UTC -3

我应该得到

utc:2015-04-01T11:42:00.269Z,日期:可选(2015-04-01 14:42:00 +0000)

那么如何将UTC日期格式转换为本地时间？

Answer 1

以下内容在Objective-C中为我工作:

// create dateFormatter with UTC time format
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss"]; 
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
NSDate *date = [dateFormatter dateFromString:@"2015-04-01T11:42:00"]; // create date from string

// change to a readable time format and change to local time zone
[dateFormatter setDateFormat:@"EEE, MMM d, yyyy - h:mm a"];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
NSString *timestamp = [dateFormatter stringFromDate:date];

我保留这两个网站,以便转换不同的时间格式:http: //www.w3.org/TR/NOTE-datetime

http://benscheirman.com/2010/06/dealing-with-dates-time-zones-in-objective-c/

在Swift中它将是:

// create dateFormatter with UTC time format
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
dateFormatter.timeZone = NSTimeZone(name: "UTC")
let date = dateFormatter.dateFromString("2015-04-01T11:42:00")// create   date from string

// change to a readable time format and change to local time zone
dateFormatter.dateFormat = "EEE, MMM d, yyyy - h:mm a"
dateFormatter.timeZone = NSTimeZone.localTimeZone()
let timeStamp = dateFormatter.stringFromDate(date!)

Answer 2

试试这个Swift扩展

Swift 4:UTC /GMT⟺本地(当前/系统)

extension Date {

    // Convert local time to UTC (or GMT)
    func toGlobalTime() -> Date {
        let timezone = TimeZone.current
        let seconds = -TimeInterval(timezone.secondsFromGMT(for: self))
        return Date(timeInterval: seconds, since: self)
    }

    // Convert UTC (or GMT) to local time
    func toLocalTime() -> Date {
        let timezone = TimeZone.current
        let seconds = TimeInterval(timezone.secondsFromGMT(for: self))
        return Date(timeInterval: seconds, since: self)
    }

}


// Try it
let utcDate = Date().toGlobalTime()
let localDate = utcDate.toLocalTime()

print("utcDate - \(utcDate)")        //Print UTC Date
print("localDate - \(localDate)")     //Print Local Date

Answer 3

swift版本的c_rath答案:

// create dateFormatter with UTC time format
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
dateFormatter.timeZone = NSTimeZone(name: "UTC")
let date = dateFormatter.dateFromString("2015-04-01T11:42:00")

// change to a readable time format and change to local time zone
dateFormatter.dateFormat = "EEE, MMM d, yyyy - h:mm a"
dateFormatter.timeZone = NSTimeZone.localTimeZone() 
let timeStamp = dateFormatter.stringFromDate(date!)

Answer 4

我不得不从 c_rath 解决方案中删除 z 和毫秒。在 swift 4 中工作。

extension String {
    func fromUTCToLocalDateTime() -> String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
        dateFormatter.timeZone = TimeZone(abbreviation: "UTC")
        var formattedString = self.replacingOccurrences(of: "Z", with: "")
        if let lowerBound = formattedString.range(of: ".")?.lowerBound {
            formattedString = "\(formattedString[..<lowerBound])"
        }

        guard let date = dateFormatter.date(from: formattedString) else {
            return self
        }

        dateFormatter.dateFormat = "EEE, MMM d, yyyy - h:mm a"
        dateFormatter.timeZone = TimeZone.current
        return dateFormatter.string(from: date)
    }
}

Answer 5

在Swift 3中,这很好用:

// create dateFormatter with UTC time format
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
dateFormatter.timeZone = TimeZone(abbreviation: "UTC")
let date = dateFormatter.date(from: "2015-04-01T11:42:00")// create date from string

// change to a readable time format and change to local time zone
dateFormatter.dateFormat = "EEE, MMM d, yyyy - h:mm a"
dateFormatter.timeZone = TimeZone.current
let timeStamp = dateFormatter.string(from: date!)

Answer 6

扩展其他人提到的内容，这是NSDateSwift 中的一个方便的扩展

import Foundation

extension NSDate {
    func ToLocalStringWithFormat(dateFormat: String) -> String {
        // change to a readable time format and change to local time zone
        let dateFormatter = NSDateFormatter()
        dateFormatter.dateFormat = dateFormat
        dateFormatter.timeZone = NSTimeZone.localTimeZone()
        let timeStamp = dateFormatter.stringFromDate(self)

        return timeStamp
    }
}