001 /* 002 * Copyright 2004 The Apache Software Foundation 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 package util; 017 018 /** 019 * HTML filter utility. 020 * 021 * @author Craig R. McClanahan 022 * @author Tim Tye 023 * @version $Revision: 267129 $ $Date: 2004-03-18 08:40:35 -0800 (Thu, 18 Mar 2004) $ 024 */ 025 026 public final class HTMLFilter { 027 028 029 /** 030 * Filter the specified message string for characters that are sensitive 031 * in HTML. This avoids potential attacks caused by including JavaScript 032 * codes in the request URL that is often reported in error messages. 033 * 034 * @param message The message string to be filtered 035 */ 036 public static String filter(String message) { 037 038 if (message == null) 039 return (null); 040 041 char content[] = new char[message.length()]; 042 message.getChars(0, message.length(), content, 0); 043 StringBuffer result = new StringBuffer(content.length + 50); 044 for (int i = 0; i < content.length; i++) { 045 switch (content[i]) { 046 case '<': 047 result.append("<"); 048 break; 049 case '>': 050 result.append(">"); 051 break; 052 case '&': 053 result.append("&"); 054 break; 055 case '"': 056 result.append("""); 057 break; 058 default: 059 result.append(content[i]); 060 } 061 } 062 return (result.toString()); 063 064 } 065 066 067 } 068