Java 防SQL注入过滤器（拦截器）代码

<web-app>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
    </welcome-file-list>
    
    <!-- 防SQL注入过滤 -->
    <filter>  
        <filter-name>SqlInjectFilter</filter-name>  
        <filter-class>com.seesun2012.web.core.filter.SqlInjectFilter</filter-class>  
        <!-- 过滤前台传入的参数，可手动添加或删减，以“|”分割 -->
        <init-param>
            <param-name>sqlInjectStrList</param-name>
            <param-value>‘|or|and|;|-|--|+|,|like|//|/|*|%|#</param-value>
        </init-param>
    </filter>
    <filter-mapping>  
        <filter-name>SqlInjectFilter</filter-name>  
        <url-pattern>/*</url-pattern>  
    </filter-mapping>
    
</web-app>

package com.seesun2012.web.core.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;

/**
 * SQL注入过滤器
 * @author CSDN：seesun2012
 * @version 0.0.1-SNAPSHOT
 * @Date 2018-01-14
 */
public class SqlInjectFilter implements Filter{
    
    public FilterConfig config;

    @Override
    public void destroy() {
        this.config = null;
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httprequest = (HttpServletRequest) request;
        // 获得所有请求参数名
        Enumeration<?> params = httprequest.getParameterNames();
        String sql = "";
        while (params.hasMoreElements()) {
            // 得到参数名
            String name = params.nextElement().toString();
            // 得到参数对应值
            String[] value = httprequest.getParameterValues(name);
            for (int i = 0; i < value.length; i++) {
                sql = sql + value[i];
            }
        }
        // 过滤掉的SQL关键字，可以手动添加
        String sqlInjectStrList = config.getInitParameter("sqlInjectStrList");
        if (sqlValidate(sql, sqlInjectStrList)) {   
            throw new IOException("请输入有效字符");
            // 重定向或跳转，略...
        } else {
            chain.doFilter(request, response);
        }
    }
          
    // 校验SQL
    protected static boolean sqlValidate(String str, String sqlInjectStrList) {
        // 统一转为小写
        str = str.toLowerCase();
        // 转换为数组
        String[] badStrs = sqlInjectStrList.split("\\|");
        for (int i = 0; i < badStrs.length; i++) {
            // 检索
            if (str.indexOf(badStrs[i]) >= 0) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        config = filterConfig;
    }

}