Java tutorial
/** * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * @author Arne Kepp, The Open Planning Project, Copyright 2008 */ package org.geowebcache.util; import java.io.IOException; import java.io.InputStream; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.net.URLEncoder; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Collections; import java.util.GregorianCalendar; import java.util.HashMap; import java.util.Iterator; import java.util.Locale; import java.util.Map; import java.util.Map.Entry; import java.util.TimeZone; import javax.servlet.http.HttpServletRequest; import org.apache.commons.collections.map.CaseInsensitiveMap; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public class ServletUtils { private static Log log = LogFactory.getLog(org.geowebcache.util.ServletUtils.class); // Calendar objects are unfortunately expensive and not thread safe :( static private Calendar calendar = new GregorianCalendar(); static private TimeZone timeZone = TimeZone.getTimeZone("GMT"); static private SimpleDateFormat format = null; static private long localOffset = TimeZone.getDefault().getRawOffset(); /** * Case insensitive lookup * * @param map * @param key * @return all matchings string */ public static String[] stringsFromMap(Map<String, String[]> map, String encoding, String key) { String[] strArray = (String[]) map.get(key); if (strArray != null) { return strArray; } else { // In case there is a case mismatch Iterator<Entry<String, String[]>> iter = map.entrySet().iterator(); while (iter.hasNext()) { Entry<String, String[]> entry = iter.next(); if (entry.getKey().equalsIgnoreCase(key)) { return URLDecode(entry.getValue(), encoding); } } } return null; } /** * Case insensitive lookup * * @param map * @param key * @return */ public static String stringFromMap(Map<String, String[]> map, String encoding, String key) { String[] strArray = stringsFromMap(map, encoding, key); if (strArray != null) { return strArray[0]; } return null; } /** * Case insensitive lookup for a couple of strings, drops everything else * * @param map * @param keys * @return */ public static String[][] selectedStringArraysFromMap(Map<String, String[]> map, String encoding, String[] keys) { String[][] retAr = new String[keys.length][]; Iterator<Entry<String, String[]>> iter = map.entrySet().iterator(); while (iter.hasNext()) { Entry<String, String[]> entry = iter.next(); String key = entry.getKey(); for (int i = 0; i < keys.length; i++) { if (key.equalsIgnoreCase(keys[i])) { retAr[i] = URLDecode(entry.getValue(), encoding); continue; } } } return retAr; } /** * Case insensitive lookup for a couple of strings, drops everything else * * @param map * @param keys * @return map subset containing (URL decoded) values for {@code keys}, with keys normalized to * upper case */ @SuppressWarnings("unchecked") public static Map<String, String> selectedStringsFromMap(Map<String, ?> map, String encoding, String... keys) { map = new CaseInsensitiveMap(map); Map<String, String> selected = new CaseInsensitiveMap(); for (String key : keys) { Object value = map.get(key); if (value != null) { String sValue = value instanceof String[] ? ((String[]) value)[0] : String.valueOf(value); selected.put(key.toUpperCase(), URLDecode(sValue, encoding)); } } return selected; } /** * Extracts the cache control header * * @param cacheControlHeader * @return Long representing expiration time in seconds */ // public static Long extractHeaderMaxAge(URLConnection backendCon) { // // String cacheControlHeader = backendCon.getHeaderField("Cache-Control"); // // if (cacheControlHeader == null) { // return null; // } // // String expression = "max-age=([0-9]*)[ ,]"; // Pattern p = Pattern.compile(expression); // Matcher m = p.matcher(cacheControlHeader.toLowerCase()); // // if (m.find()) { // return Long.valueOf(m.group(1)); // } else { // return null; // } // } /** * Reads an inputstream and stores all the information in a buffer. * * @param is * the inputstream * @param bufferHint * hint for the total buffer, -1 = 10240 * @param tmpBufferSize * how many bytes to read at a time, -1 = 1024 * * @return a compacted buffer with all the data * @throws IOException */ public static byte[] readStream(InputStream is, int bufferHint, int tmpBufferSize) throws IOException { return readStream(is, bufferHint, tmpBufferSize, true); } public static byte[] readStream(InputStream is, int bufferHint, int tmpBufferSize, boolean close) throws IOException { byte[] buffer = null; if (bufferHint > 0) { buffer = new byte[bufferHint]; } else { buffer = new byte[10240]; } byte[] tmpBuffer = null; if (tmpBufferSize > 0) { tmpBuffer = new byte[tmpBufferSize]; } else { tmpBuffer = new byte[1024]; } int totalCount = 0; int c = is.read(tmpBuffer); while (c != -1) { if (c != 0) { totalCount += c; // Expand buffer if needed if (totalCount >= buffer.length) { int newLength = buffer.length * 2; if (newLength < totalCount) newLength = totalCount; byte[] newBuffer = new byte[newLength]; System.arraycopy(buffer, 0, newBuffer, 0, buffer.length); buffer = newBuffer; } System.arraycopy(tmpBuffer, 0, buffer, (totalCount - c), c); } c = is.read(tmpBuffer); } if (close) is.close(); // Compact buffer byte[] newBuffer = new byte[totalCount]; System.arraycopy(buffer, 0, newBuffer, 0, totalCount); return newBuffer; } /** * Makes HTTP Expire header value * * Has to be synchronized due to the shared Calendar objects * * @param seconds * @return */ public static String makeExpiresHeader(int seconds) { return formatTimestamp(System.currentTimeMillis() + seconds * 1000L); } public static String formatTimestamp(long timestamp) { String ret; synchronized (calendar) { if (ServletUtils.format == null) { ServletUtils.format = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z", Locale.US); ServletUtils.format.setTimeZone(ServletUtils.timeZone); } calendar.setTimeInMillis(timestamp); ret = format.format(calendar.getTime()); } return ret; } /** * Returns the expiration time in milliseconds from now * * @param expiresHeader * @return */ public static long parseExpiresHeader(String expiresHeader) { if (expiresHeader == null) { return -1; } long ret; synchronized (calendar) { if (ServletUtils.format == null) { ServletUtils.format = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z", Locale.US); ServletUtils.format.setTimeZone(ServletUtils.timeZone); } try { format.parse(expiresHeader); } catch (ParseException pe) { log.debug("Cannot parse " + expiresHeader + ", " + pe.getMessage()); return -1; } ret = calendar.getTimeInMillis() - System.currentTimeMillis() - localOffset; } return ret; } public static String hexOfBytes(byte[] bytes) { StringBuilder str = new StringBuilder(bytes.length * 2); for (int i = 0; i < bytes.length; i++) { str.append(hexOfByte(bytes[i])); } return str.toString(); } /** * Converts a byte to a hex String * * @param aByte * @return */ public static String hexOfByte(byte aByte) { char[] str = new char[2]; for (int i = 0; i < 2; i++) { int temp = (int) aByte; if (temp < 0) { temp += 256; } if (i == 0) { temp = temp / 16; } else { temp = temp % 16; } if (temp > 9) { switch (temp) { case 10: str[i] = 'A'; break; case 11: str[i] = 'B'; break; case 12: str[i] = 'C'; break; case 13: str[i] = 'D'; break; case 14: str[i] = 'E'; break; case 15: str[i] = 'F'; break; } } else { str[i] = (char) temp; } } return new String(str); } public static String URLEncode(String str) { String ret = null; try { ret = URLEncoder.encode(str, "UTF-8"); } catch (UnsupportedEncodingException e) { log.debug(e.getMessage()); } return ret; } public static String URLDecode(String str, String encoding) { String ret = null; if (encoding != null) { try { ret = URLDecoder.decode(str, encoding); } catch (UnsupportedEncodingException e) { log.debug(e.getMessage()); } } try { ret = URLDecoder.decode(str, "UTF-8"); } catch (UnsupportedEncodingException e1) { log.debug(e1.getMessage()); } return ret; } private static String[] URLDecode(String[] values, String encoding) { String[] decodedValues = new String[values.length]; for (int i = 0; i < values.length; i++) { decodedValues[i] = URLDecode(values[i], encoding); } return decodedValues; } public static String gwcHtmlHeader(String pageTitle) { return "<head>\n" + "<title>" + pageTitle + "</title>" + "<style type=\"text/css\">\n" + "body, td, th {\n" + "font-family: Verdana,Arial,\'Bitstream Vera Sans\',Helvetica,sans-serif;\n" + "font-size: 0.85em;\n" + "vertical-align: top;\n" + "}\n" + "table.stats tbody + tbody tr * {padding-top: 1em;}\n" + "table.stats tbody + tbody tr + tr * {padding-top: inherit;}\n" + "table.stats th[scope=row] {text-align: right}\n" + "table.stats th[scope=col] {text-align: left}\n" + "</style>\n" + "</head>\n"; } public static String gwcHtmlLogoLink(String relBasePath) { return "<a id=\"logo\" href=\"" + relBasePath + "\">" + "<img src=\"" + relBasePath + "rest/web/geowebcache_logo.png\"" + "height=\"70\" width=\"247\" border=\"0\"/>" + "</a>\n"; } public static long[][] arrayDeepCopy(long[][] array) { long[][] ret = new long[array.length][array[0].length]; for (int i = 0; i < array.length; i++) { System.arraycopy(array[i], 0, ret[i], 0, array[i].length); } return ret; } /** * Replaces occurrences of > and < with HTML equivalents * * @param str * @return */ public static String disableHTMLTags(String str) { if (str == null) { return "null"; } return str.replaceAll("<", "<").replaceAll(">", ">"); } public static Map<String, String> queryStringToMap(String queryString) { if (queryString == null || queryString.length() == 0) { return Collections.emptyMap(); } String[] params = queryString.split("&"); Map<String, String> ret = new HashMap<String, String>(); for (String kvp : params) { String[] split = kvp.split("="); if (split[0].length() > 0) { ret.put(split[0], split[1]); } } return ret; } /** * Generate the base url of the request, minus the context path * @param req servlet request * @return Base url of request, minus the context path */ public static String getServletBaseURL(HttpServletRequest req, String servletPrefix) { String result; if (req.getServerPort() == 80 || req.getServerPort() == 443) { result = req.getScheme() + "://" + req.getServerName(); } else { result = req.getScheme() + "://" + req.getServerName() + ":" + req.getServerPort(); } if (servletPrefix == null) { return result; } else { // If the servlet is embeded within another, include the context path of the parent // servlet in the base. String reqUrl = req.getContextPath(); return result + reqUrl; } } /** * Generate the context path of the request, less the specified trailing path * @param req * @param trailingPath */ public static String getServletContextPath(HttpServletRequest req, String trailingPath, String servletPrefix) { String reqUrl = req.getRequestURL().toString(); String servletBase = ServletUtils.getServletBaseURL(req, servletPrefix); int prefixIdx = servletBase.length(); int suffixIdx = reqUrl.indexOf(trailingPath); String context = reqUrl.substring(prefixIdx, suffixIdx); return context; } }