UTC时间格式有很多，需要辨清自己是属于哪种格式，否则会出错

"EEE, dd MMM yy HH:mm:ss z",
"EEE, dd MMM yyyy HH:mm:ss z",   
"EEE, dd MMM yy HH:mm:ss",   
"EEE, MMM dd yy HH:mm:ss",   
"EEE, dd MMM yy HH:mm z",   
"EEE dd MMM yyyy HH:mm:ss",   
"dd MMM yy HH:mm:ss z",   
"dd MMM yy HH:mm z",   
"yyyy-MM-dd'T'HH:mm:ssZ",   
"yyyy-MM-dd'T'HH:mm:ss'Z'",   
"yyyy-MM-dd'T'HH:mm:sszzzz",   
"yyyy-MM-dd'T'HH:mm:ss z",   
"yyyy-MM-dd'T'HH:mm:ssz",   
"yyyy-MM-dd'T'HH:mm:ss.SSSz",   
"yyyy-MM-dd'T'HHmmss.SSSz",   
"yyyy-MM-dd'T'HH:mm:ss",   
"yyyy-MM-dd'T'HH:mmZ",   
"yyyy-MM-dd'T'HH:mm'Z'",   
"dd MMM yyyy HH:mm:ss z",   
"dd MMM yyyy HH:mm z",   
"yyyy-MM-dd",   
"MMM dd, yyyy"};

UTC时间是世界时间，北京时间应在UTC时间+上8小时

• 格式: 2019-05-21T08:44:00Z

public static void main(String[] args) throws Exception{ 
        Date date = null;
        // ISO 8601 slightly modified */"yyyy-MM-dd'T'HH:mm:ss'Z'",
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
        // 2019-05-21T08:44:00Z 对应的时间格式 yyyy-MM-dd'T'HH:mm:ss'Z'
        date = sdf.parse("2019-05-21T08:44:00Z");
        System.out.println("UTC时间："+date);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR,calendar.get(Calendar.HOUR)+8);
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date1 = calendar.getTime();
        String date2 = simpleDateFormat.format(calendar.getTime());
        System.out.println("北京时间："+date2);
    }

• 格式: 2020-09-18T06:44:32.552Z

public static void main(String[] args) throws Exception{ 
        Date date = null;
        // ISO 8601 slightly modified */"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        // 2020-09-18T06:44:32.552Z 对应的时间格式 yyyy-MM-dd'T'HH:mm:ss.SSS'Z'
        date = sdf.parse("2020-09-18T06:44:32.552Z");
        System.out.println("UTC时间："+date);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR,calendar.get(Calendar.HOUR)+8);
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date1 = calendar.getTime();
        String date2 = simpleDateFormat.format(calendar.getTime());
        System.out.println("北京时间："+date2);
    }