使用拦截器拦截html参数

　　 公司最新需求：根据传递的参数进行业务判断，如果符合条件则继续后面的业务逻辑，否则跳转到指定的错误页面。有些是请求的controller 使用了spring aop的方式进行验证；但是有些是html页面，这些是需要使用过滤器了。

1.框架是spring mvc框架

添加自定义的过滤器

package cn.zm518.news.filter;

import cn.zm518.circle.client.entity.CircleStateVo;
import cn.zm518.circle.client.service.CircleClient;
import cn.zm518.common.properties.SystemProperties;
import cn.zm518.news.common.util.StringUtil;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * @Author fan
 * @Date 2018/07/18
 * 拦截封号的文章列表以及详情页
 */
public class CircleFilter extends OncePerRequestFilter {


    public static final String shequnHost = SystemProperties.getInstance().getProperty("community.rpc.url");

    public static final String url = SystemProperties.getInstance().getProperty("seal.circle.url");

    public static final int CIRCLE_STEAL = 2; //社群是否被封号

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        // 请求的uri
        String uri = request.getRequestURI();
        // uri跳转到文章列表以及详情时才进行过滤
        if (uri.indexOf("statics/html/article") == 1) {
                // 执行过滤
                // 获取登录的社群circleId
                String circleId = request.getParameter("circleId");
                if (StringUtils.isNotBlank(circleId)) {
                    CircleClient circleClient = CircleClient.getInstance(shequnHost);

                    CircleStateVo circleStateVo =  circleClient.getCircleStateVo(circleId);

                    if (circleStateVo != null && circleStateVo.getState() == CIRCLE_STEAL){
                        // 如果session中不存在登录者实体，则弹出框提示重新登录
                        // 设置request和response的字符集，防止乱码
                        request.setCharacterEncoding("UTF-8");
                        response.setCharacterEncoding("UTF-8");
                        PrintWriter out = response.getWriter();
                         StringBuilder builder = new StringBuilder();
                        builder.append("<script type=\"text/javascript\">");
                        builder.append("window.top.location.href='");
                        builder.append(url);
                        builder.append("';");
                        builder.append("</script>");
                        out.print(builder.toString());
                    }

                } else {

                    filterChain.doFilter(request, response);
                }
        } else {
            filterChain.doFilter(request, response);
        }
    }
}

2.在web.xml添加自定义的过滤器

 <filter>
    <filter-name>sessionFilter</filter-name>
    <filter-class>cn.zm518.news.filter.CircleFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>sessionFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

3.比如请求本地的html页面

http://localhost:8068/statics/html/article.html?circleId=4f98421633973cf75-7fef&newsId=41df20164b5c0c282-7ffe&followerId=&from=singlemessage

会先进入自定义过滤器，如果不满足条件，则会优先过滤掉。负责会跳过继续执行后面的业务逻辑。