Filter使用范例--登陆验证

Filter使用范例--登陆验证，具体效果和过程看博文 http://blog.csdn.net/evankaka/article/details/45480101

package com.mucfc;

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.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
	/** 
	 *  
	 * 权限过滤器 
	 *  
	 * */    
	public class AuthorityFilter implements Filter {
		 private FilterConfig config;  
		@Override
		public void destroy（） {
			 this.config=null;  
		}

		@Override
		public void doFilter（ServletRequest request ServletResponse response
				FilterChain chain） throws IOException ServletException {
			//获取Filter配置参数  
	        String encoding=config.getInitParameter（“encoding“）;  
	        String loginPage=config.getInitParameter（“loginPage“）;  
	        String afterLogin=config.getInitParameter（“afterLogin“）;  
	        //设置request编码  
	        request.setCharacterEncoding（encoding）;  
	        HttpServletRequest requ=（HttpServletRequest） request;  
	        HttpSession session=requ.getSession（）;  
	        //获取客户请求页面  
	        String requestPath=requ.getServletPath（）;   
	        String name=requ.getParameter（“username“）;
	        	if（name==““||name==null）{  
	            System.out.println（“权限拦截器的消息：“+“终止“）;  
	         HttpServletResponse resq=（HttpServletResponse）response;
	            resq.sendRedirect（requ.getContextPath（）+loginPage）;
	        }else{  
	            System.out.println（“权限拦截器的消息：“+“放行“）;  
	            request.setCharacterEncoding（“UTF-8“）;
	            chain.doFilter（request response）;  
	        }  
		}

		@Override
		public void init（FilterConfig config） throws ServletException {
			this.config=config; 
		}   
		
	}

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2015-05-04 16:33  ServletLearningChapter2_2\
     文件         841  2015-05-04 16:33  ServletLearningChapter2_2\.classpath
     文件        1058  2015-05-04 16:33  ServletLearningChapter2_2\.project
     目录           0  2015-05-04 16:41  ServletLearningChapter2_2\.settings\
     文件         503  2015-05-04 16:33  ServletLearningChapter2_2\.settings\.jsdtscope
     文件         106  2015-05-04 16:44  ServletLearningChapter2_2\.settings\org.eclipse.core.resources.prefs
     文件         364  2015-05-04 16:33  ServletLearningChapter2_2\.settings\org.eclipse.jdt.core.prefs
     文件         527  2015-05-04 16:33  ServletLearningChapter2_2\.settings\org.eclipse.wst.common.component
     文件         345  2015-05-04 16:33  ServletLearningChapter2_2\.settings\org.eclipse.wst.common.project.facet.core.xml
     文件          49  2015-05-04 16:33  ServletLearningChapter2_2\.settings\org.eclipse.wst.jsdt.ui.superType.container
     文件           6  2015-05-04 16:33  ServletLearningChapter2_2\.settings\org.eclipse.wst.jsdt.ui.superType.name
     目录           0  2015-05-04 16:33  ServletLearningChapter2_2\build\
     目录           0  2015-05-17 13:48  ServletLearningChapter2_2\build\classes\
     目录           0  2015-05-17 13:48  ServletLearningChapter2_2\build\classes\com\
     目录           0  2015-05-17 13:48  ServletLearningChapter2_2\build\classes\com\mucfc\
     文件        2663  2015-05-17 13:48  ServletLearningChapter2_2\build\classes\com\mucfc\AuthorityFilter.class
     目录           0  2015-05-04 16:33  ServletLearningChapter2_2\src\
     目录           0  2015-05-04 16:33  ServletLearningChapter2_2\src\com\
     目录           0  2015-05-04 16:34  ServletLearningChapter2_2\src\com\mucfc\
     文件        1897  2015-05-04 18:35  ServletLearningChapter2_2\src\com\mucfc\AuthorityFilter.java
     目录           0  2015-05-04 16:41  ServletLearningChapter2_2\WebContent\
     文件         567  2015-05-04 18:31  ServletLearningChapter2_2\WebContent\Login.jsp
     文件         519  2015-05-04 17:32  ServletLearningChapter2_2\WebContent\Main.jsp
     目录           0  2015-05-04 16:33  ServletLearningChapter2_2\WebContent\meta-INF\
     文件          39  2015-05-04 16:33  ServletLearningChapter2_2\WebContent\meta-INF\MANIFEST.MF
     目录           0  2015-05-04 16:40  ServletLearningChapter2_2\WebContent\WEB-INF\
     目录           0  2015-05-04 16:33  ServletLearningChapter2_2\WebContent\WEB-INF\lib\
     文件        1086  2015-05-04 18:42  ServletLearningChapter2_2\WebContent\WEB-INF\web.xml