package com.xialiu.shop.web.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 SqlFilter implements Filter{

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		// TODO Auto-generated method stub
		
	}

	@Override
	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    
        @SuppressWarnings("rawtypes")  
        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)) {    
            res.sendRedirect("error.html");    
            //String ip = req.getRemoteAddr();    
        } else {    
            chain.doFilter(req, res);    
        }    
	}

	@Override
	public void destroy() {
		// TODO Auto-generated method stub
		
	}
	
	//效验    
    protected static boolean sqlValidate(String str) {    
        str = str.toLowerCase();//统一转为小写    
        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;    
    }    
}