Servlet过滤器大全

import  javax.servlet. * ; 
import  java.io.IOException; 

/** */ /**  
* 用于设置 HTTP 请求字符编码的过滤器，通过过滤器参数encoding指明使用何种字符编码,用于处理Html Form请求参数的中文问题 
*/  
public   class  CharacterEncodingFilter 
implements  Filter 
{ 
protected  FilterConfig filterConfig  =   null ; 
protected  String encoding  =   "" ; 

public   void  doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)  throws  IOException, ServletException 
{ 
if (encoding  !=   null ) 
servletRequest.setCharacterEncoding(encoding); 
filterChain.doFilter(servletRequest, servletResponse); 
}  

public   void  destroy() 
{ 
filterConfig  =   null ; 
encoding  =   null ; 
}  

public   void  init(FilterConfig filterConfig)  throws  ServletException 
{ 
this .filterConfig  =  filterConfig; 
this .encoding  =  filterConfig.getInitParameter( " encoding " ); 

}  
}  

import  javax.servlet. * ; 
import  javax.servlet.http.HttpServletResponse; 
import  java.io.IOException; 

/** */ /**  
* 用于的使 Browser 不缓存页面的过滤器 
*/  
public   class  ForceNoCacheFilter  implements  Filter  { 

public   void  doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)  throws  IOException, ServletException 
{ 
((HttpServletResponse) response).setHeader( " Cache-Control " , " no-cache " ); 
((HttpServletResponse) response).setHeader( " Pragma " , " no-cache " ); 
((HttpServletResponse) response).setDateHeader ( " Expires " ,  - 1 ); 
filterChain.doFilter(request, response); 
}  

public   void  destroy()  { 
}  

public   void  init(FilterConfig filterConfig)  throws  ServletException  { 
}  
}  

import  javax.servlet. * ; 
import  javax.servlet.http.HttpServletRequest; 
import  javax.servlet.http.HttpServletResponse; 
import  javax.servlet.http.HttpSession; 
import  java.util.List; 
import  java.util.ArrayList; 
import  java.util.StringTokenizer; 
import  java.io.IOException; 

/** */ /**  
* 用于检测用户是否登陆的过滤器，如果未登录，则重定向到指的登录页面 


* 配置参数 


* checkSessionKey 需检查的在 Session 中保存的关键字 

* redirectURL 如果用户未登录，则重定向到指定的页面，URL不包括 ContextPath 

* notCheckURLList 不做检查的URL列表，以分号分开，并且 URL 中不包括 ContextPath 

*/  
public   class  CheckLoginFilter 
implements  Filter 
{ 
protected  FilterConfig filterConfig  =   null ; 
private  String redirectURL  =   null ; 
private  List notCheckURLList  =   new  ArrayList(); 
private  String sessionKey  =   null ; 

public   void  doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)  throws  IOException, ServletException 
{ 
HttpServletRequest request  =  (HttpServletRequest) servletRequest; 
HttpServletResponse response  =  (HttpServletResponse) servletResponse; 

HttpSession session  =  request.getSession(); 
if (sessionKey  ==   null ) 
{ 
filterChain.doFilter(request, response); 
return ; 
}  
if (( ! checkRequestURIIntNotFilterList(request))  &&  session.getAttribute(sessionKey)  ==   null ) 
{ 
response.sendRedirect(request.getContextPath()  +  redirectURL); 
return ; 
}  
filterChain.doFilter(servletRequest, servletResponse); 
}  

public   void  destroy() 
{ 
notCheckURLList.clear(); 
}  

private   boolean  checkRequestURIIntNotFilterList(HttpServletRequest request) 
{ 
String uri  =  request.getServletPath()  +  (request.getPathInfo()  ==   null   ?   ""  : request.getPathInfo()); 
return  notCheckURLList.contains(uri); 
}  

public   void  init(FilterConfig filterConfig)  throws  ServletException 
{ 
this .filterConfig  =  filterConfig; 
redirectURL  =  filterConfig.getInitParameter( " redirectURL " ); 
sessionKey  =  filterConfig.getInitParameter( " checkSessionKey " ); 

String notCheckURLListStr  =  filterConfig.getInitParameter( " notCheckURLList " ); 

if (notCheckURLListStr  !=   null ) 
{ 
StringTokenizer st  =   new  StringTokenizer(notCheckURLListStr,  " ; " ); 
notCheckURLList.clear(); 
while (st.hasMoreTokens()) 
{ 
notCheckURLList.add(st.nextToken()); 
}  
}  
}  
}  

package  catalog.view.util; 

import  javax.servlet.Filter; 
import  javax.servlet.FilterConfig; 
import  javax.servlet.ServletRequest; 
import  javax.servlet.ServletResponse; 
import  javax.servlet.FilterChain; 
import  javax.servlet.ServletException; 
import  javax.servlet.http.HttpServletRequest; 
import  java.io.IOException; 
import  java.util.Iterator; 
import  java.util.Set; 
import  java.util.HashSet; 
//  
import  org.apache.commons.logging.Log; 
import  org.apache.commons.logging.LogFactory; 

/** */ /**  
* This Filter class handle the security of the application. 
* 
* It should be configured inside the web.xml. 
* 
*  @author  Derek Y. Shen 
*/  
public   class  SecurityFilter  implements  Filter  { 
// the login page uri 
private   static   final  String LOGIN_PAGE_URI  =   " login.jsf " ; 

// the logger object 
private  Log logger  =  LogFactory.getLog( this .getClass()); 

// a set of restricted resources 
private  Set restrictedResources; 

/** */ /**  
* Initializes the Filter. 
*/  
public   void  init(FilterConfig filterConfig)  throws  ServletException  { 
this .restrictedResources  =   new  HashSet(); 
this .restrictedResources.add( " /createProduct.jsf " ); 
this .restrictedResources.add( " /editProduct.jsf " ); 
this .restrictedResources.add( " /productList.jsf " ); 
}  

/** */ /**  
* Standard doFilter object. 
*/  
public   void  doFilter(ServletRequest req, ServletResponse res, FilterChain chain) 
throws  IOException, ServletException  { 
this .logger.debug( " doFilter " ); 

String contextPath  =  ((HttpServletRequest)req).getContextPath(); 
String requestUri  =  ((HttpServletRequest)req).getRequestURI(); 

this .logger.debug( " contextPath =  "   +  contextPath); 
this .logger.debug( " requestUri =  "   +  requestUri); 

if  ( this .contains(requestUri, contextPath)  &&   ! this .authorize((HttpServletRequest)req))  { 
this .logger.debug( " authorization failed " ); 
((HttpServletRequest)req).getRequestDispatcher(LOGIN_PAGE_URI).forward(req, res); 
}  
else   { 
this .logger.debug( " authorization succeeded " ); 
chain.doFilter(req, res); 
}  
}  

public   void  destroy()  {}  

private   boolean  contains(String value, String contextPath)  { 
Iterator ite  =   this .restrictedResources.iterator(); 

while  (ite.hasNext())  { 
String restrictedResource  =  (String)ite.next(); 

if  ((contextPath  +  restrictedResource).equalsIgnoreCase(value))  { 
return   true ; 
}  
}  

return   false ; 
}  

private   boolean  authorize(HttpServletRequest req)  { 

// 处理用户登录 
/**/ /*  UserBean user = (UserBean)req.getSession().getAttribute(BeanNames.USER_BEAN); 

if (user != null && user.getLoggedIn()) { 
//user logged in 
return true; 
} 
else { 
return false; 
} */  
}  
}  

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; 

public   class  RightFilter  implements  Filter  { 

public   void  destroy()  { 

}  

public   void  doFilter(ServletRequest sreq, ServletResponse sres, FilterChain arg2)  throws  IOException, ServletException  { 
//  获取uri地址 
HttpServletRequest request = (HttpServletRequest)sreq; 
String uri  =  request.getRequestURI(); 
String ctx = request.getContextPath(); 
uri  =  uri.substring(ctx.length()); 
// 判断admin级别网页的浏览权限 
if (uri.startsWith( " /admin " ))  { 
if (request.getSession().getAttribute( " admin " ) == null )  { 
request.setAttribute( " message " , " 您没有这个权限 " ); 
request.getRequestDispatcher( " /login.jsp " ).forward(sreq,sres); 
return ; 
}  
}  
// 判断manage级别网页的浏览权限 
if (uri.startsWith( " /manage " ))  { 
// 这里省去 
}  
}  
// 下面还可以添加其他的用户权限，省去。 

}  

public   void  init(FilterConfig arg0)  throws  ServletException  { 

}  

} 

<!--  判断页面的访问权限  -->  
< filter >  
< filter - name > RightFilter </ filter - name >  
< filter - class > cn.itkui.filter.RightFilter </ filter - class >  
</ filter >  
< filter - mapping >  
< filter - name > RightFilter </ filter - name >  
< url - pattern >/ admin /**/ /* </url-pattern> 
</filter-mapping> 
<filter-mapping> 
<filter-name>RightFilter</filter-name> 
<url-pattern>/manage/*</url-pattern> 
</filter-mapping> 

在web.xml中加入Filter的配置，如下： 
<filter> 

<filter-name>EncodingAndCacheflush</filter-name> 
<filter-class>EncodingAndCacheflush</filter-class> 
<init-param> 
<param-name>encoding</param-name> 
<param-value>UTF-8</param-value> 
</init-param> 
</filter> 
<filter-mapping> 
<filter-name>EncodingAndCacheflush</filter-name> 
<url-pattern>/*</url-pattern> 
</filter-mapping> 

要传递参数的时候最好使用form进行传参，如果使用链接的话当中文字符的时候过滤器转码是不会起作用的，还有就是页面上

http://maqianli.iteye.com/blog/290423