Java获取指定时区的时间戳

「爱情、让人受尽委屈。」 2023-02-20 06:47 120阅读 0赞

### 1. 前言 ###

本文主要讲，在`Java`中如何通过一个标准格式时间字符串（`"yyyy-MM-dd HH:mm:ss"`），来获取其对应的各个时区的时间戳信息。

### 2. 代码示例 ###

**功能代码：**  
获取时间字符串对应的指定时区的时间戳

public static long getTimeZoneTimeStr(String dateStr,String timeZone) {
            long result = 0L;
            int year;
            int month;
            int day;
            int hour;
            int minute;
            int second;
            Calendar calendarTime = Calendar.getInstance();
    
            if(timeZone != null){
                TimeZone tz = TimeZone.getTimeZone(timeZone);
                calendarTime.setTimeZone(tz);
            }
    
            if (null != dateStr && 14 == dateStr.length()) {
                year = Integer.parseInt(dateStr.substring(0, 4));
                month = Integer.parseInt(dateStr.substring(4, 6));
                day = Integer.parseInt(dateStr.substring(6, 8));
                hour = Integer.parseInt(dateStr.substring(8, 10));
                minute = Integer.parseInt(dateStr.substring(10, 12));
                second = Integer.parseInt(dateStr.substring(12, 14));
                calendarTime.set(1, year);
                calendarTime.set(2, month - 1);
                calendarTime.set(5, day);
                calendarTime.set(11, hour);
                calendarTime.set(12, minute);
                calendarTime.set(13, second);
                result = calendarTime.getTime().getTime();
            }else if (null != dateStr && 19 == dateStr.length()) {
                year = Integer.parseInt(dateStr.substring(0, 4));
                month = Integer.parseInt(dateStr.substring(5, 7));
                day = Integer.parseInt(dateStr.substring(8, 10));
                hour = Integer.parseInt(dateStr.substring(11, 13));
                minute = Integer.parseInt(dateStr.substring(14, 16));
                second = Integer.parseInt(dateStr.substring(17, 19));
                calendarTime.set(1, year);
                calendarTime.set(2, month - 1);
                calendarTime.set(5, day);
                calendarTime.set(11, hour);
                calendarTime.set(12, minute);
                calendarTime.set(13, second);
                result = calendarTime.getTime().getTime();
            }
    
            return result;
        }

**调用示例：**

public static void main(String[] args) {
            System.out.println("-------------------- 2019-09-24 00:00:00 -----------------------");
            System.out.println("local: "+getTimeZoneTimeStr("2019-09-24 00:00:00",null));
            System.out.println("Asia/Shanghai: "+getTimeZoneTimeStr("2019-09-24 00:00:00","Asia/Shanghai"));
            System.out.println("GMT+0800: "+getTimeZoneTimeStr("2019-09-24 00:00:00","GMT+0800"));
            System.out.println("GMT: "+getTimeZoneTimeStr("2019-09-24 00:00:00","GMT"));
            System.out.println("UTC: "+getTimeZoneTimeStr("2019-09-24 00:00:00","UTC"));
    
            System.out.println("-------------------- 2019-09-23 16:00:00 -----------------------");
            System.out.println("local: "+getTimeZoneTimeStr("2019-09-23 16:00:00",null));
            System.out.println("Asia/Shanghai: "+getTimeZoneTimeStr("2019-09-23 16:00:00","Asia/Shanghai"));
            System.out.println("GMT+0800: "+getTimeZoneTimeStr("2019-09-23 16:00:00","GMT+0800"));
            System.out.println("GMT: "+getTimeZoneTimeStr("2019-09-23 16:00:00","GMT"));
            System.out.println("UTC: "+getTimeZoneTimeStr("2019-09-23 16:00:00","UTC"));
        }

**程序运行结果：**

-------------------- 2019-09-24 00:00:00 -----------------------
    local: 1569254400072
    Asia/Shanghai: 1569254400115
    GMT+0800: 1569254400115
    GMT: 1569283200115
    UTC: 1569283200115
    -------------------- 2019-09-23 16:00:00 -----------------------
    local: 1569225600116
    Asia/Shanghai: 1569225600116
    GMT+0800: 1569225600116
    GMT: 1569254400116
    UTC: 1569254400116

### 3. 总结 ###

运行结果可以看出，在`Java`中`Date.getTime()`获取到的时间戳其实是`东8区`的时间`“2019-09-24 00:00:00”`（即返回的是`北京时间1970年01月1日0点0分0秒`以来的毫秒数，对应`UTC时间1970年01月1日8点0分0秒`以来的毫秒数，其数值大小等于`0时区的“2019-09-23 16:00:00”所对应的时间戳`）所对应得时间戳。