encodingfilter.java

java web模拟的简单的一个网络硬盘

package com.dark.comm.web;

import javax.servlet.http.HttpServlet;
import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.FilterChain;
import javax.servlet.http.*;
import java.io.IOException;

/**
 * 公共包，字符过滤器
 * </p>
 * <p>
 * Copyright: Copyright (c) 2005
 * </p>
 * @author dark.xie
 * @version 1.0
 */

@SuppressWarnings("serial")
public class EncodingFilter extends HttpServlet implements Filter {

	private FilterConfig filterConfig;

	private String targetEncoding = "ASCII";

	/**
	 * Called by the web container to indicate to a filter that it is being
	 * placed into service.
	 * 
	 * @param filterConfig
	 *            FilterConfig
	 * @throws ServletException
	 * @todo Implement this javax.servlet.Filter method
	 */
	public void init(FilterConfig filterConfig) throws ServletException {
		this.filterConfig = filterConfig;
		this.targetEncoding = filterConfig.getInitParameter("encoding");
	}

	/**
	 * The <code>doFilter</code> method of the Filter is called by the
	 * container each time a request/response pair is passed through the chain
	 * due to a client request for a resource at the end of the chain.
	 * 
	 * @param request
	 *            ServletRequest
	 * @param response
	 *            ServletResponse
	 * @param chain
	 *            FilterChain
	 * @throws IOException
	 * @throws ServletException
	 * @todo Implement this javax.servlet.Filter method
	 */
	public void doFilter(ServletRequest srequest, ServletResponse sresponse,
			FilterChain chain) throws IOException, ServletException {
		try {
			HttpServletRequest request = (HttpServletRequest) srequest;
			request.setCharacterEncoding(targetEncoding);
			chain.doFilter(srequest, sresponse);
		} catch (ServletException sx) {
			filterConfig.getServletContext().log(sx.getMessage());
		} catch (IOException iox) {
			filterConfig.getServletContext().log(iox.getMessage());
		}
	}

	/**
	 * Called by the web container to indicate to a filter that it is being
	 * taken out of service.
	 * 
	 * @todo Implement this javax.servlet.Filter method
	 */
	public void destroy() {
		filterConfig = null;
		targetEncoding = null;
	}

}