Calendar TimeZone SimpleDateFormat

时间 2019-11-13

标签 calendar timezone simpledateformat 繁體版

原文原文链接

关于Calendar类的使用可参考：Java Calendar类的使用总结html

获取日历(Calendar)：java.util.Calendar#getInstance()java

获取时区TimeZone：orm

TimeZone.getTimeZone("GMT+00:00"); 或：TimeZone.getTimeZone("UTC");
TimeZone.getTimeZone("GMT+08:00"); 或：TimeZone.getTimeZone("CTT"); 或：TimeZone.getTimeZone("Asia/Shanghai");

ZoneID可参考：java.time.ZoneId#SHORT_IDShtm

default TimeZone设定：blog

一、java.util.TimeZone#setDefault(TimeZone zone)get

二、VM options：-Duser.timezone=UTC源码

语言环境Locale：java.util.Locale#SIMPLIFIED_CHINESE（中国大陆）io

Calendar calendar = Calendar.getInstance();
Calendar calendar = Calendar.getInstance("UTC");
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT+08:00"));
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("Asia/Shanghai"));
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("CTT"));
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("CTT"), Locale.SIMPLIFIED_CHINESE);

calendar.set(Calendar.YEAR, 2099);
calendar.get(Calendar.HOUR_OF_DAY); //能够获取传入TimeZone对应的时间
calendar.getTime(); //获取的依然是defaultTimeZone对应的时间

java.util.Calendar#getTime 源码：
public final Date getTime() {
    return new Date(getTimeInMillis());
}
所以，经过calendar.getTime()获取的依然是defaultTimeZone对应的时间

SimpleDateFormat转变时区：form

DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
format.setTimeZone(TimeZone.getTimeZone("CTT"));
format.format(new Date());
format.format(calendar.getTime());