防止SQL注入和XSS攻击Filter

一个是Filter负责将请求的request包装一下。

一个是request包装器，负责过滤掉非法的字符。

将这个过滤器配置上以后，世界总算清净多了。。

代码如下：

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;

/**
 * {@link CharLimitFilter}
 *
 * 拦截防止sql注入
 *
 * @author Administrator
 */
public class XssFilter implements Filter {


/* (non-Javadoc)
 * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
 */
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException,
ServletException {

XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper(
(HttpServletRequest) request);
filterChain.doFilter(xssRequest, response);

}

}

包装器：

/**
 * {@link XssHttpServletRequestWrapper}
 *
 * TODO : document me
 *
 * @author Administrator
 */
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。

* 如果需要获得原始的值，则通过super.getParameterValues(name)来获取

* 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。

* 如果需要获得原始的值，则通过super.getHeaders(name)来获取

* 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 || "".equals(s)) {
return s;
}
StringBuilder sb = new StringBuilder(s.length() + 16);
for (int i = 0; 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;
}

}