Here you can find the source of determineDateFormat(String dateString)
| Parameter | Description |
|---|---|
| dateString | The date string to determine the SimpleDateFormat pattern for. |
public static String determineDateFormat(String dateString) throws ParseException
//package com.java2s; /*/*w w w. j av a2s. co m*/ * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ import java.text.ParseException; import java.util.*; public class Main { private static final Map<String, String> DATE_FORMAT_REGEXPS = new HashMap<String, String>() { private static final long serialVersionUID = 1L; { put("^\\d{8}$", "yyyyMMdd"); put("^\\d{1,2}-\\d{1,2}-\\d{4}$", "dd-MM-yyyy"); put("^\\d{4}-\\d{1,2}-\\d{1,2}$", "yyyy-MM-dd"); put("^\\d{1,2}/\\d{1,2}/\\d{4}$", "MM/dd/yyyy"); put("^\\d{4}/\\d{1,2}/\\d{1,2}$", "yyyy/MM/dd"); put("^\\d{1,2}\\s[a-z]{3}\\s\\d{4}$", "dd MMM yyyy"); put("^\\d{1,2}\\s[a-z]{4,}\\s\\d{4}$", "dd MMMM yyyy"); put("^\\d{12}$", "yyyyMMddHHmm"); put("^\\d{8}\\s\\d{4}$", "yyyyMMdd HHmm"); put("^\\d{1,2}-\\d{1,2}-\\d{4}\\s\\d{1,2}:\\d{2}$", "dd-MM-yyyy HH:mm"); put("^\\d{4}-\\d{1,2}-\\d{1,2}\\s\\d{1,2}:\\d{2}$", "yyyy-MM-dd HH:mm"); put("^\\d{1,2}/\\d{1,2}/\\d{4}\\s\\d{1,2}:\\d{2}$", "MM/dd/yyyy HH:mm"); put("^\\d{4}/\\d{1,2}/\\d{1,2}\\s\\d{1,2}:\\d{2}$", "yyyy/MM/dd HH:mm"); put("^\\d{1,2}\\s[a-z]{3}\\s\\d{4}\\s\\d{1,2}:\\d{2}$", "dd MMM yyyy HH:mm"); put("^\\d{1,2}\\s[a-z]{4,}\\s\\d{4}\\s\\d{1,2}:\\d{2}$", "dd MMMM yyyy HH:mm"); put("^\\d{14}$", "yyyyMMddHHmmss"); put("^\\d{8}\\s\\d{6}$", "yyyyMMdd HHmmss"); put("^\\d{1,2}-\\d{1,2}-\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "dd-MM-yyyy HH:mm:ss"); put("^\\d{4}-\\d{1,2}-\\d{1,2}\\s\\d{1,2}:\\d{2}:\\d{2}$", "yyyy-MM-dd HH:mm:ss"); put("^\\d{1,2}/\\d{1,2}/\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "MM/dd/yyyy HH:mm:ss"); put("^\\d{4}/\\d{1,2}/\\d{1,2}\\s\\d{1,2}:\\d{2}:\\d{2}$", "yyyy/MM/dd HH:mm:ss"); put("^\\d{1,2}\\s[a-z]{3}\\s\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "dd MMM yyyy HH:mm:ss"); put("^\\d{1,2}\\s[a-z]{4,}\\s\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "dd MMMM yyyy HH:mm:ss"); } }; /** * Determine SimpleDateFormat pattern matching with the given date string. Returns null if format is unknown. You * can simply extend DateUtil with more formats if needed. * * @param dateString * The date string to determine the SimpleDateFormat pattern for. * @return The matching SimpleDateFormat pattern, or null if format is unknown. * @see java.text.SimpleDateFormat */ public static String determineDateFormat(String dateString) throws ParseException { for (String regexp : DATE_FORMAT_REGEXPS.keySet()) if (dateString.toLowerCase().matches(regexp)) return DATE_FORMAT_REGEXPS.get(regexp); throw new ParseException("unable to parse date", 0); } }