Java tutorial
package com.cloudlbs.core.utils; /** * 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 with * the License. You may obtain a copy of the License at * * 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.io.IOException; import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Arrays; import java.util.Calendar; import java.util.Collection; import java.util.Date; import java.util.Iterator; import java.util.Locale; import java.util.TimeZone; /** * This class has some code from HttpClient DateUtil. <br/> * <br/> * See also package <code>org.apache.solr.common.util<code> */ public class DateUtil { // start HttpClient /** * Date format pattern used to parse HTTP date headers in RFC 1123 format. */ public static final String PATTERN_RFC1123 = "EEE, dd MMM yyyy HH:mm:ss zzz"; /** * Date format pattern used to parse HTTP date headers in RFC 1036 format. */ public static final String PATTERN_RFC1036 = "EEEE, dd-MMM-yy HH:mm:ss zzz"; /** * Date format pattern used to parse HTTP date headers in ANSI C * <code>asctime()</code> format. */ public static final String PATTERN_ASCTIME = "EEE MMM d HH:mm:ss yyyy"; // These are included for back compat private static final Collection<String> DEFAULT_HTTP_CLIENT_PATTERNS = Arrays.asList(PATTERN_ASCTIME, PATTERN_RFC1036, PATTERN_RFC1123); private static final Date DEFAULT_TWO_DIGIT_YEAR_START; static { Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"), Locale.US); calendar.set(2000, Calendar.JANUARY, 1, 0, 0); DEFAULT_TWO_DIGIT_YEAR_START = calendar.getTime(); } private static final TimeZone GMT = TimeZone.getTimeZone("GMT"); // end HttpClient // --------------------------------------------------------------------------------------- /** * A suite of default date formats that can be parsed, and thus transformed * to the Solr specific format */ public static final Collection<String> DEFAULT_DATE_FORMATS = new ArrayList<String>(); static { DEFAULT_DATE_FORMATS.add("yyyy-MM-dd'T'HH:mm:ss'Z'"); DEFAULT_DATE_FORMATS.add("yyyy-MM-dd'T'HH:mm:ss"); DEFAULT_DATE_FORMATS.add("yyyy-MM-dd"); DEFAULT_DATE_FORMATS.add("yyyy-MM-dd hh:mm:ss"); DEFAULT_DATE_FORMATS.add("yyyy-MM-dd HH:mm:ss"); DEFAULT_DATE_FORMATS.add("EEE MMM d hh:mm:ss z yyyy"); DEFAULT_DATE_FORMATS.addAll(DEFAULT_HTTP_CLIENT_PATTERNS); } /** * Returns a formatter that can be use by the current thread if needed to * convert Date objects to the Internal representation. * * @param d * The input date to parse * @return The parsed {@link java.util.Date} * @throws java.text.ParseException * If the input can't be parsed * @throws org.apache.commons.httpclient.util.DateParseException * If the input can't be parsed */ public static Date parseDate(String d) throws ParseException { return parseDate(d, DEFAULT_DATE_FORMATS); } public static Date parseDate(String d, Collection<String> fmts) throws ParseException { // 2007-04-26T08:05:04Z if (d.endsWith("Z") && d.length() > 20) { return getThreadLocalDateFormat().parse(d); } return parseDate(d, fmts, null); } /** * Slightly modified from * org.apache.commons.httpclient.util.DateUtil.parseDate * <p/> * Parses the date value using the given date formats. * * @param dateValue * the date value to parse * @param dateFormats * the date formats to use * @param startDate * During parsing, two digit years will be placed in the range * <code>startDate</code> to <code>startDate + 100 years</code>. * This value may be <code>null</code>. When <code>null</code> is * given as a parameter, year <code>2000</code> will be used. * @return the parsed date * @throws ParseException * if none of the dataFormats could parse the dateValue */ public static Date parseDate(String dateValue, Collection<String> dateFormats, Date startDate) throws ParseException { if (dateValue == null) { throw new IllegalArgumentException("dateValue is null"); } if (dateFormats == null) { dateFormats = DEFAULT_HTTP_CLIENT_PATTERNS; } if (startDate == null) { startDate = DEFAULT_TWO_DIGIT_YEAR_START; } // trim single quotes around date if present // see issue #5279 if (dateValue.length() > 1 && dateValue.startsWith("'") && dateValue.endsWith("'")) { dateValue = dateValue.substring(1, dateValue.length() - 1); } SimpleDateFormat dateParser = null; Iterator<String> formatIter = dateFormats.iterator(); while (formatIter.hasNext()) { String format = (String) formatIter.next(); if (dateParser == null) { dateParser = new SimpleDateFormat(format, Locale.US); dateParser.setTimeZone(GMT); dateParser.set2DigitYearStart(startDate); } else { dateParser.applyPattern(format); } try { return dateParser.parse(dateValue); } catch (ParseException pe) { // ignore this exception, we will try the next format } } // we were unable to parse the date throw new ParseException("Unable to parse the date " + dateValue, 0); } /** * Returns a formatter that can be use by the current thread if needed to * convert Date objects to the Internal representation. * * @return The {@link java.text.DateFormat} for the current thread */ public static DateFormat getThreadLocalDateFormat() { return fmtThreadLocal.get(); } public static TimeZone UTC = TimeZone.getTimeZone("UTC"); private static ThreadLocalDateFormat fmtThreadLocal = new ThreadLocalDateFormat(); private static class ThreadLocalDateFormat extends ThreadLocal<DateFormat> { DateFormat proto; public ThreadLocalDateFormat() { super(); // 2007-04-26T08:05:04Z SimpleDateFormat tmp = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.US); tmp.setTimeZone(UTC); proto = tmp; } @Override protected DateFormat initialValue() { return (DateFormat) proto.clone(); } } /** * Formats the date and returns the calendar instance that was used (which * may be reused) */ public static Calendar formatDate(Date date, Calendar cal, Appendable out) throws IOException { // using a stringBuilder for numbers can be nice since // a temporary string isn't used (it's added directly to the // builder's buffer. StringBuilder sb = out instanceof StringBuilder ? (StringBuilder) out : new StringBuilder(); if (cal == null) cal = Calendar.getInstance(TimeZone.getTimeZone("GMT"), Locale.US); cal.setTime(date); int i = cal.get(Calendar.YEAR); sb.append(i); sb.append('-'); i = cal.get(Calendar.MONTH) + 1; // 0 based, so add 1 if (i < 10) sb.append('0'); sb.append(i); sb.append('-'); i = cal.get(Calendar.DAY_OF_MONTH); if (i < 10) sb.append('0'); sb.append(i); sb.append('T'); i = cal.get(Calendar.HOUR_OF_DAY); // 24 hour time format if (i < 10) sb.append('0'); sb.append(i); sb.append(':'); i = cal.get(Calendar.MINUTE); if (i < 10) sb.append('0'); sb.append(i); sb.append(':'); i = cal.get(Calendar.SECOND); if (i < 10) sb.append('0'); sb.append(i); i = cal.get(Calendar.MILLISECOND); if (i != 0) { sb.append('.'); if (i < 100) sb.append('0'); if (i < 10) sb.append('0'); sb.append(i); // handle canonical format specifying fractional // seconds shall not end in '0'. Given the slowness of // integer div/mod, simply checking the last character // is probably the fastest way to check. int lastIdx = sb.length() - 1; if (sb.charAt(lastIdx) == '0') { lastIdx--; if (sb.charAt(lastIdx) == '0') { lastIdx--; } sb.setLength(lastIdx + 1); } } sb.append('Z'); if (out != sb) out.append(sb); return cal; } }