如何在Java中获取给定的日期字符串格式（模式）？

import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.regex.Matcher;import java.util.regex.Pattern;public class NewClass {    private static final String[] formats = {      "yyyy-MM-dd'T'HH:mm:ss'Z'",   "yyyy-MM-dd'T'HH:mm:ssZ",     "yyyy-MM-dd'T'HH:mm:ss",      "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",     "yyyy-MM-dd'T'HH:mm:ss.SSSZ", "yyyy-MM-dd HH:mm:ss",      "MM/dd/yyyy HH:mm:ss",        "MM/dd/yyyy'T'HH:mm:ss.SSS'Z'",      "MM/dd/yyyy'T'HH:mm:ss.SSSZ", "MM/dd/yyyy'T'HH:mm:ss.SSS",      "MM/dd/yyyy'T'HH:mm:ssZ",     "MM/dd/yyyy'T'HH:mm:ss",      "yyyy:MM:dd HH:mm:ss",        "yyyyMMdd", };            public static void main(String[] args) {        String yyyyMMdd = "20110917";parse(yyyyMMdd);    }    public static void parse(String d) {        if (d != null) { for (String parse : formats) {     SimpleDateFormat sdf = new SimpleDateFormat(parse);     try {         sdf.parse(d);         System.out.println("Printing the value of " + parse);     } catch (ParseException e) {     } }        }    }}