Java 得到UTC标准时间

SimpleDateFormat foo = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

System.out.println("foo:"+foo.format(new Date()));

Calendar gc = GregorianCalendar.getInstance();

System.out.println("gc.getTime():"+gc.getTime());

System.out.println("gc.getTimeInMillis():"+new Date(gc.getTimeInMillis()));

//当前系统默认时区的时间：

Calendar calendar=new GregorianCalendar();

System.out.print("时区："+calendar.getTimeZone().getID()+"  ");

System.out.println("时间："+calendar.get(Calendar.HOUR_OF_DAY)+":"+calendar.get(Calendar.MINUTE));

//美国洛杉矶时区

TimeZone tz=TimeZone.getTimeZone("America/Los_Angeles");

//时区转换

calendar.setTimeZone(tz);

System.out.print("时区："+calendar.getTimeZone().getID()+"  ");

System.out.println("时间："+calendar.get(Calendar.HOUR_OF_DAY)+":"+calendar.get(Calendar.MINUTE));

Date time=new Date();

//1、取得本地时间：

java.util.Calendar cal = java.util.Calendar.getInstance();

 

//2、取得时间偏移量：

int zoneOffset = cal.get(java.util.Calendar.ZONE_OFFSET);

 

//3、取得夏令时差：

int dstOffset = cal.get(java.util.Calendar.DST_OFFSET);

 

//4、从本地时间里扣除这些差量，即可以取得UTC时间：

cal.add(java.util.Calendar.MILLISECOND, -(zoneOffset + dstOffset));

 

//之后调用cal.get(int x)或cal.getTimeInMillis()方法所取得的时间即是UTC标准时间。

System.out.println("UTC:"+new Date(cal.getTimeInMillis()));

Calendar calendar1 = Calendar.getInstance();

TimeZone tztz = TimeZone.getTimeZone("GMT");       

calendar1.setTimeZone(tztz);

System.out.println(calendar.getTime());

System.out.println(calendar.getTimeInMillis());