// 得到不同分类下的相同文章

	public List<ArticleInfo> getTheSameArticle(String args){

	  String[] arr = args.split(",");

	   int len=arr.length;

		String sql="select article_id from"

				+ " (select category_id,article_id from article_category WHERE category_id in ("+args

				+ ")  GROUP BY category_id,article_id)b GROUP BY article_id HAVING count(category_id)="+len;

		 System.out.println(sql);

		 List <Map<String, Long>> resultList=articleCategoryMapper.selectByCategories(sql );

		System.out.println(resultList);

		LinkedList<ArticleInfo> articleList=new LinkedList<>();

		for (int i=0;i<resultList.size();i++) {

			System.out.println(resultList.get(i));

			Map<String, Long> tempMap = resultList.get(i);

			System.out.println(tempMap.get("article_id"));

			long id=tempMap.get("article_id");

		   articleList.add(getOneById(id));

		}

		return articleList;

	}