如何将本地日期转换为格林尼治标准时间

这个怎么样 -

public static void main(String[] args) throws IOException {    Test test=new Test();    Date fromDate = Calendar.getInstance().getTime();    System.out.println("UTC Time - "+fromDate);    System.out.println("GMT Time - "+test.cvtToGmt(fromDate));}private  Date cvtToGmt( Date date ){    TimeZone tz = TimeZone.getDefault();    Date ret = new Date( date.getTime() - tz.getRawOffset() );    // if we are now in DST, back off by the delta.  Note that we are checking the GMT date, this is the KEY.    if ( tz.inDaylightTime( ret )){        Date dstDate = new Date( ret.getTime() - tz.getDSTSavings() );        // check to make sure we have not crossed back into standard time        // this happens when we are on the cusp of DST (7pm the day before the change for PDT)        if ( tz.inDaylightTime( dstDate )){ ret = dstDate;        }     }     return ret;}

测试结果 ：
UTC时间-5月15日星期二16:24:14 IST 2012
GMT时间-5月15日星期二10:54:14 IST 2012