Java tutorial
/** * 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. */ package org.apache.falcon.util; import org.apache.commons.lang3.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.servlet.http.HttpServletRequest; /** * Utility functions for dealing with servlets. */ public final class Servlets { private static final Logger LOG = LoggerFactory.getLogger(Servlets.class); public static final String REQUEST_ID = "requestId"; private Servlets() { /* singleton */ } /** * Returns the user of the given request. * * @param httpRequest an HTTP servlet request * @return the user */ public static String getUserFromRequest(HttpServletRequest httpRequest) { LOG.info("HttpServletRequest RemoteUser is " + httpRequest.getRemoteUser()); String user = httpRequest.getRemoteUser(); if (!StringUtils.isEmpty(user)) { return user; } LOG.info("HttpServletRequest user.name param value is " + httpRequest.getParameter("user.name")); user = httpRequest.getParameter("user.name"); // available in query-param if (!StringUtils.isEmpty(user)) { return user; } LOG.info("HttpServletRequest user.name from remote-header is " + httpRequest.getParameter("user.name")); user = httpRequest.getHeader("Remote-User"); // backwards-compatibility if (!StringUtils.isEmpty(user)) { return user; } return null; } /** * Returns the URI of the given request. * * @param httpRequest an HTTP servlet request * @return the URI, including the query string */ public static String getRequestURI(HttpServletRequest httpRequest) { final StringBuilder url = new StringBuilder(100).append(httpRequest.getRequestURI()); if (httpRequest.getQueryString() != null) { url.append('?').append(httpRequest.getQueryString()); } return url.toString(); } /** * Returns the full URL of the given request. * * @param httpRequest an HTTP servlet request * @return the full URL, including the query string */ public static String getRequestURL(HttpServletRequest httpRequest) { final StringBuilder url = new StringBuilder(100).append(httpRequest.getRequestURL()); if (httpRequest.getQueryString() != null) { url.append('?').append(httpRequest.getQueryString()); } return url.toString(); } }