java UTC时间和local时间相互转换

    /**
     * local时间转换成UTC时间
     * @param localTime
     * @return
     */
    public static Date localToUTC(String localTime) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date localDate= null;
        try {
            localDate = sdf.parse(localTime);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        long localTimeInMillis=localDate.getTime();
        /** long时间转换成Calendar */
        Calendar calendar= Calendar.getInstance();
        calendar.setTimeInMillis(localTimeInMillis);
        /** 取得时间偏移量 */
        int zoneOffset = calendar.get(java.util.Calendar.ZONE_OFFSET);
        /** 取得夏令时差 */
        int dstOffset = calendar.get(java.util.Calendar.DST_OFFSET);
        /** 从本地时间里扣除这些差量，即可以取得UTC时间*/
        calendar.add(java.util.Calendar.MILLISECOND, -(zoneOffset + dstOffset));
        /** 取得的时间就是UTC标准时间 */
        Date utcDate=new Date(calendar.getTimeInMillis());
        return utcDate;
    }

    /**
     * utc时间转成local时间
     * @param utcTime
     * @return
     */
    public static Date utcToLocal(String utcTime){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        Date utcDate = null;
        try {
            utcDate = sdf.parse(utcTime);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        sdf.setTimeZone(TimeZone.getDefault());
        Date locatlDate = null;
        String localTime = sdf.format(utcDate.getTime());
        try {
            locatlDate = sdf.parse(localTime);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return locatlDate;
    }