| /* |
| * Copyright 2004 The Apache Software Foundation |
| * |
| * Licensed 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 filters; |
| |
| |
| import java.io.IOException; |
| import javax.servlet.Filter; |
| import javax.servlet.FilterChain; |
| import javax.servlet.FilterConfig; |
| import javax.servlet.ServletException; |
| import javax.servlet.ServletRequest; |
| import javax.servlet.ServletResponse; |
| import javax.servlet.UnavailableException; |
| |
| |
| /** |
| * <p>Example filter that sets the character encoding to be used in parsing the |
| * incoming request, either unconditionally or only if the client did not |
| * specify a character encoding. Configuration of this filter is based on |
| * the following initialization parameters:</p> |
| * <ul> |
| * <li><strong>encoding</strong> - The character encoding to be configured |
| * for this request, either conditionally or unconditionally based on |
| * the <code>ignore</code> initialization parameter. This parameter |
| * is required, so there is no default.</li> |
| * <li><strong>ignore</strong> - If set to "true", any character encoding |
| * specified by the client is ignored, and the value returned by the |
| * <code>selectEncoding()</code> method is set. If set to "false, |
| * <code>selectEncoding()</code> is called <strong>only</strong> if the |
| * client has not already specified an encoding. By default, this |
| * parameter is set to "true".</li> |
| * </ul> |
| * |
| * <p>Although this filter can be used unchanged, it is also easy to |
| * subclass it and make the <code>selectEncoding()</code> method more |
| * intelligent about what encoding to choose, based on characteristics of |
| * the incoming request (such as the values of the <code>Accept-Language</code> |
| * and <code>User-Agent</code> headers, or a value stashed in the current |
| * user's session.</p> |
| * |
| * @author Craig McClanahan |
| * @version $Revision$ $Date$ |
| */ |
| |
| public class SetCharacterEncodingFilter implements Filter { |
| |
| |
| // ----------------------------------------------------- Instance Variables |
| |
| |
| /** |
| * The default character encoding to set for requests that pass through |
| * this filter. |
| */ |
| protected String encoding = null; |
| |
| |
| /** |
| * The filter configuration object we are associated with. If this value |
| * is null, this filter instance is not currently configured. |
| */ |
| protected FilterConfig filterConfig = null; |
| |
| |
| /** |
| * Should a character encoding specified by the client be ignored? |
| */ |
| protected boolean ignore = true; |
| |
| |
| // --------------------------------------------------------- Public Methods |
| |
| |
| /** |
| * Take this filter out of service. |
| */ |
| public void destroy() { |
| |
| this.encoding = null; |
| this.filterConfig = null; |
| |
| } |
| |
| |
| /** |
| * Select and set (if specified) the character encoding to be used to |
| * interpret request parameters for this request. |
| * |
| * @param request The servlet request we are processing |
| * @param result The servlet response we are creating |
| * @param chain The filter chain we are processing |
| * |
| * @exception IOException if an input/output error occurs |
| * @exception ServletException if a servlet error occurs |
| */ |
| public void doFilter(ServletRequest request, ServletResponse response, |
| FilterChain chain) |
| throws IOException, ServletException { |
| |
| // Conditionally select and set the character encoding to be used |
| if (ignore || (request.getCharacterEncoding() == null)) { |
| String encoding = selectEncoding(request); |
| if (encoding != null) |
| request.setCharacterEncoding(encoding); |
| } |
| |
| // Pass control on to the next filter |
| chain.doFilter(request, response); |
| |
| } |
| |
| |
| /** |
| * Place this filter into service. |
| * |
| * @param filterConfig The filter configuration object |
| */ |
| public void init(FilterConfig filterConfig) throws ServletException { |
| |
| this.filterConfig = filterConfig; |
| this.encoding = filterConfig.getInitParameter("encoding"); |
| String value = filterConfig.getInitParameter("ignore"); |
| if (value == null) |
| this.ignore = true; |
| else if (value.equalsIgnoreCase("true")) |
| this.ignore = true; |
| else if (value.equalsIgnoreCase("yes")) |
| this.ignore = true; |
| else |
| this.ignore = false; |
| |
| } |
| |
| |
| // ------------------------------------------------------ Protected Methods |
| |
| |
| /** |
| * Select an appropriate character encoding to be used, based on the |
| * characteristics of the current request and/or filter initialization |
| * parameters. If no character encoding should be set, return |
| * <code>null</code>. |
| * <p> |
| * The default implementation unconditionally returns the value configured |
| * by the <strong>encoding</strong> initialization parameter for this |
| * filter. |
| * |
| * @param request The servlet request we are processing |
| */ |
| protected String selectEncoding(ServletRequest request) { |
| |
| return (this.encoding); |
| |
| } |
| |
| |
| } |