setcharacterencodingfilter.java

struts+spring +hibernate查询分页

	/*
	* 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 com.baidu.common;

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;


	/**
	 * <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: 1.3 $ $Date: 2006/06/29 07:15:48 $
	 */

	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 {
	    	//javax.servlet.http.HttpServletRequest req = (javax.servlet.http.HttpServletRequest)request;
	    	//Authenticator auth = (Authenticator)req.getSession().getAttribute(Constants.SESSION_AUTH);
	        // 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);
	        }
	        //if( auth == null ){
	   			//RequestDispatcher dispatcher = request.getRequestDispatcher("/login.jsp");
	   			//dispatcher.forward(request,response);
	        //}
		// 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);

	    }

}