Java防止SQL注入2（通过filter过滤器功能进行拦截）

痛定思痛。 2022-04-25 03:56 155阅读 0赞

首先说明一点，这个过滤器拦截其实是不靠谱的，比如说我的一篇文章是介绍sql注入的，或者评论的内容是有关sql的，那会过滤掉；且如果每个页面都经过这个过滤器，那么效率也是非常低的。

如果是要SQL注入拦截，可以在数据访问上层的业务层用方法的形式进行手动过滤还靠谱些。

或者使用SQL的参数形式进行，这个绝对是百分百搞得定。

关于SQL注入解释，参考：[http://www.cnblogs.com/EasonJim/p/6223216.html][http_www.cnblogs.com_EasonJim_p_6223216.html]

关于filter过滤器使用教程，参考：[http://www.runoob.com/servlet/servlet-writing-filters.html][http_www.runoob.com_servlet_servlet-writing-filters.html]

使用filter过滤器实现的代码如下：

web.xml:

<filter>
        <filter-name>antiSqlInjection</filter-name>
        <filter-class>com.tarena.dingdang.filter.AntiSqlInjectionfilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>antiSqlInjection</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

filter:

package com.jsoft.jblog.filter;
     
    import java.io.IOException;
    import java.util.Enumeration;
     
    
    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;
    import javax.servlet.http.HttpServletResponse;
     
    public class AntiSqlInjectionfilter implements Filter {
     
        public void destroy() {
            // TODO Auto-generated method stub
        }
         
        public void init(FilterConfig arg0) throws ServletException {
            // TODO Auto-generated method stub
        }
         
        public void doFilter(ServletRequest args0, ServletResponse args1,
                FilterChain chain) throws IOException, ServletException {
            HttpServletRequest req=(HttpServletRequest)args0;
            HttpServletResponse res=(HttpServletResponse)args1;
             //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");
                //String ip = req.getRemoteAddr();
            } else {
                chain.doFilter(args0,args1);
            }
        }
         
        //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'|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]) >= 0) {
                    return true;
                }
            }
            return false;
        }
    }

参考：[http://www.oschina.net/code/snippet\_811941\_14131][http_www.oschina.net_code_snippet_811941_14131]

==>如有问题，请联系我：easonjim\#163.com，或者下方发表评论。<==

[http_www.cnblogs.com_EasonJim_p_6223216.html]: http://www.cnblogs.com/EasonJim/p/6223216.html
[http_www.runoob.com_servlet_servlet-writing-filters.html]: http://www.runoob.com/servlet/servlet-writing-filters.html
[http_www.oschina.net_code_snippet_811941_14131]: http://www.oschina.net/code/snippet_811941_14131