用过滤器防sql注入

川长思鸟来 2022-12-30 08:03 141阅读 0赞

使用过滤器是解决sql注入的一种方式，其它可以前端校验处理等

过滤器写法：

package XXX.utils;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.util.Enumeration;
    
    /**
     * sql注入过滤器
     * @Date 2020/12/24
     **/
    public class SqlInjectionFilter implements Filter{
    
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    
            HttpServletRequest req = (HttpServletRequest) request;
            HttpServletResponse res = (HttpServletResponse) response;
            //获得所有请求参数名
            Enumeration params = req.getParameterNames();
    
            String sql = "";
            while (params.hasMoreElements()) {
                //得到参数名
                String name = params.nextElement().toString();
                //System.out.println("name===========================" + name + "--");
                //得到参数对应值
                String[] value = req.getParameterValues(name);
                for (int i = 0; i < value.length; i++) {
                    sql = sql + value[i];
                }
            }
            //System.out.println("============================SQL"+sql);
            //有sql关键字，跳转到error.html
            if (sqlValidate(sql)) {
                throw new IOException("您发送请求中的参数中含有非法字符");
            } else {
                chain.doFilter(req, res);
            }
        }
    
        //效验
        protected static boolean sqlValidate(String str) {
            str = str.toLowerCase();//统一转为小写
            //String badStr = "'|and|exec|execute|insert|select|delete|update|count|drop|*|%|chr|mid|master|truncate|char|declare|sitename|net user|xp_cmdshell|;|or|-|+|,|like";
            String badStr = "'|and|exec|execute|insert|create|drop|table|from|grant|use|group_concat|column_name|" +
                    "information_schema.columns|table_schema|union|where|select|delete|update|order|by|count|*|" +
                    "chr|mid|master|truncate|char|declare|or|;|-|--|+|,|like|//|/|%|#";//过滤掉的sql关键字，可以手动添加
            String[] badStrs = badStr.split("\\|");
            for (int i = 0; i < badStrs.length; i++) {
                if (str.indexOf(badStrs[i]) !=-1) {
                    return true;
                }
            }
            return false;
        }
    
        public void init(FilterConfig filterConfig) throws ServletException {
            //throw new UnsupportedOperationException("Not supported yet.");
        }
    
        public void destroy() {
            //throw new UnsupportedOperationException("Not supported yet.");
        }
    
    }

web.xml中做配置

<filter>
        <filter-name>SqlInjectionFilter</filter-name>
        <filter-class>com.hnac.hzinfo.common.utils.SqlInjectionFilter</filter-class>
      </filter>
      <filter-mapping>
        <filter-name>SqlInjectionFilter</filter-name>
        <url-pattern>/*</url-pattern>
      </filter-mapping>