使用Servlet Filter来防止SQL注入的方法

使用Servlet Filter来防止SQL注入的方法
参考:http://618119.com/archives/2010/02/23/156.html

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 ReqFilter implements Filter {


public void init(FilterConfig config) throws ServletException {
}


public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
ReqHttpServletRequestWrapper reqRequest = new ReqHttpServletRequestWrapper(
(HttpServletRequest) request);
chain.doFilter(reqRequest, response);
}


public void destroy() {
}
}

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;


public class ReqHttpServletRequestWrapper extends HttpServletRequestWrapper {
	HttpServletRequest orgRequest = null;

	public ReqHttpServletRequestWrapper(HttpServletRequest request) {
		super(request);
		orgRequest = request;
	}

	/**
	 * 覆盖getParameter方法，将参数名和参数值都做req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(name);
		if (value != null) {
			value = reqEncode(value);
		}
		return value;
	}

	/**
	 * 覆盖getHeader方法，将参数名和参数值都做req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(reqEncode(name));
		if (value != null) {
			value = reqEncode(value);
		}
		return value;
	}*/

	/**
	 * 将容易引起req漏洞的半角字符直接替换成全角字符
	 * 
	 * @param s
	 * @return
	 */
	private static String reqEncode(String s) {
		if (s == null || "".equals(s)) {
			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("&prime;");// &acute;");
				break;
			case '′':
				sb.append("&prime;");// &acute;");
				break;
			case '\"':
				sb.append("&quot;");
				break;
			case '＂':
				sb.append("&quot;");
				break;
			case '&':
				sb.append("＆");
				break;
			case '#':
				sb.append("＃");
				break;
			case '\\':
				sb.append('￥');
				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 ReqHttpServletRequestWrapper) {
			return ((ReqHttpServletRequestWrapper) req).getOrgRequest();
		}

		return req;
	}
}

 <filter>
  <display-name>reqFilter</display-name>
  <filter-name>reqFilter</filter-name>
  <filter-class>jp.co.bsnw.servlet.ReqFilter</filter-class>
 </filter>
 <filter-mapping>
  <filter-name>reqFilter</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>