/** * Http and Servlet tool classes. * */ public abstract class ServletUtils { //-- Content Type Definition--// public static final String EXCEL_TYPE = "application/vnd.ms-excel"; public static final String HTML_TYPE = "text/html"; public static final String JS_TYPE = "text/javascript"; public static final String JSON_TYPE = "application/json"; public static final String XML_TYPE = "text/xml"; public static final String TEXT_TYPE = "text/plain"; //-- Header definition--// public static final String AUTHENTICATION_HEADER = "Authorization"; //-- Common value definitions--// public static final long ONE_YEAR_SECONDS = 60 * 60 * 24 * 365; /** * Header that sets the client cache expiration time. */ public static void setExpiresHeader(HttpServletResponse response, long expiresSeconds) { //Http 1.0 header response.setDateHeader("Expires", System.currentTimeMillis() + expiresSeconds * 1000); //Http 1.1 header response.setHeader("Cache-Control", "private, max-age=" + expiresSeconds); } /** * Set the Header that prohibits client-side caching. */ public static void setDisableCacheHeader(HttpServletResponse response) { //Http 1.0 header response.setDateHeader("Expires", 1L); response.addHeader("Pragma", "no-cache"); //Http 1.1 header response.setHeader("Cache-Control", "no-cache, no-store, max-age=0"); } /** * Set LastModified Header. */ public static void setLastModifiedHeader(HttpServletResponse response, long lastModifiedDate) { response.setDateHeader("Last-Modified", lastModifiedDate); } /** * Set Etag Header. */ public static void setEtag(HttpServletResponse response, String etag) { response.setHeader("ETag", etag); } /** * Calculate whether the file has been modified according to the browser's If-Modified-Since Header. * * If there is no modification, checkIfModify returns false, set 304 not modify status. * * @param lastModified The last modification time of the content. */ public static boolean checkIfModifiedSince(HttpServletRequest request, HttpServletResponse response, long lastModified) { long ifModifiedSince = request.getDateHeader("If-Modified-Since"); if ((ifModifiedSince != -1) && (lastModified < ifModifiedSince + 1000)) { response.setStatus(HttpServletResponse.SC_NOT_MODIFIED); return false; } return true; } /** * According to the browser's If-None-Match Header, calculate whether the Etag is invalid. * * If Etag is valid, checkIfNoneMatch returns false, set 304 not modify status. * * ETag of @param etag content. */ public static boolean checkIfNoneMatchEtag(HttpServletRequest request, HttpServletResponse response, String etag) { String headerValue = request.getHeader("If-None-Match"); if (headerValue != null) { boolean conditionSatisfied = false; if (!"*".equals(headerValue)) { StringTokenizer commaTokenizer = new StringTokenizer(headerValue, ","); while (!conditionSatisfied && commaTokenizer.hasMoreTokens()) { String currentToken = commaTokenizer.nextToken(); if (currentToken.trim().equals(etag)) { conditionSatisfied = true; } } } else { conditionSatisfied = true; } if (conditionSatisfied) { response.setStatus(HttpServletResponse.SC_NOT_MODIFIED); response.setHeader("ETag", etag); return false; } } return true; } /** * Set the Header that makes the browser pop up the download dialog. * * @param fileName The downloaded filename. */ public static void setFileDownloadHeader(HttpServletResponse response, String fileName) { try { //Chinese file name support String encodedfileName = new String(fileName.getBytes(), "ISO8859-1"); response.setHeader("Content-Disposition", "attachment; filename=\"" + encodedfileName + "\""); } catch (UnsupportedEncodingException e) { } } /** * Get Request Parameters with the same prefix. * * The parameter name of the returned result has the prefix removed. */ public static Map<String, Object> getParametersStartingWith(ServletRequest request, String prefix) { AssertUtils.notNull(request, "Request must not be null"); Enumeration paramNames = request.getParameterNames(); Map<String, Object> params = new TreeMap<String, Object>(); if (prefix == null) { prefix = ""; } while (paramNames != null && paramNames.hasMoreElements()) { String paramName = (String) paramNames.nextElement(); if ("".equals(prefix) || paramName.startsWith(prefix)) { String unprefixed = paramName.substring(prefix.length()); String[] values = request.getParameterValues(paramName); if (values == null || values.length == 0) { // Do nothing, no values found at all. } else if (values.length > 1) { params.put(unprefixed, values); } else { params.put(unprefixed, values[0]); } } } return params; } /** * The client encodes the Header verified by Http Basic. */ public static String encodeHttpBasic(String userName, String password) { String encode = userName + ":" + password; return "Basic " + EncodeUtils.encodeBase64(encode.getBytes()); } }