JSP过滤器防止Xss漏洞的实现方法(分享)

package filter; 
 
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 XssFilter implements Filter { 
 
public void init(FilterConfig config) throws ServletException { 
} 
 
public void doFilter(ServletRequest request, ServletResponse response, 
FilterChain chain) throws IOException, ServletException  
{ 
XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper( 
(HttpServletRequest) request); 
chain.doFilter(xssRequest, response); 
} 
 
public void destroy() { 
} 
} 

package filter; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletRequestWrapper; 
 
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper { 
HttpServletRequest orgRequest = null; 
 
public XssHttpServletRequestWrapper(HttpServletRequest request) { 
super(request); 
orgRequest = request; 
} 
 
/** 
* 覆盖getParameter方法，将参数名和参数值都做xss过滤。<br/> 
* 如果需要获得原始的值，则通过super.getParameterValues(name)来获取<br/> 
* getParameterNames,getParameterValues和getParameterMap也可能需要覆盖 
*/ 
@Override 
public String getParameter(String name) { 
String value = super.getParameter(xssEncode(name)); 
if (value != null) { 
value = xssEncode(value); 
} 
return value; 
} 
 
/** 
* 覆盖getHeader方法，将参数名和参数值都做xss过滤。<br/> 
* 如果需要获得原始的值，则通过super.getHeaders(name)来获取<br/> 
* getHeaderNames 也可能需要覆盖 
*/ 
@Override 
public String getHeader(String name) { 
 
String value = super.getHeader(xssEncode(name)); 
if (value != null) { 
value = xssEncode(value); 
} 
return value; 
} 
 
/** 
* 将容易引起xss漏洞的半角字符直接替换成全角字符 
* 
* @param s 
* @return 
*/ 
private static String xssEncode(String s) { 
if (s == null || s.isEmpty()) { 
return s; 
} 
StringBuilder sb = new StringBuilder(s.length() + 16); 
for (int i = 0; i < s.length(); i++) { 
char c = s.charAt(i); 
switch (c) { 
case '>': 
sb.append('＞');//全角大于号 
break; 
case '<': 
sb.append('＜');//全角小于号 
break; 
case '\'': 
sb.append('‘');//全角单引号 
break; 
case '\"': 
sb.append('“');//全角双引号 
break; 
case '&': 
sb.append('＆');//全角 
break; 
case '\\': 
sb.append('＼');//全角斜线 
break; 
case '#': 
sb.append('＃');//全角井号 
break; 
default: 
sb.append(c); 
break; 
} 
} 
return sb.toString(); 
} 
 
/** 
* 获取最原始的request 
* 
* @return 
*/ 
public HttpServletRequest getOrgRequest() { 
return orgRequest; 
} 
/** 
* 获取最原始的request的静态方法 
* 
* @return 
*/ 
public static HttpServletRequest getOrgRequest(HttpServletRequest req) { 
if(req instanceof XssHttpServletRequestWrapper){ 
return ((XssHttpServletRequestWrapper)req).getOrgRequest(); 
} 
 
return req; 
} 
} 

<filter> 
<filter-name>xssFilter</filter-name> 
<filter-class>filter.XssFilter</filter-class> 
</filter> 
<filter-mapping> 
<filter-name>xssFilter</filter-name> 
<url-pattern>/*</url-pattern> 
</filter-mapping>