elasticsearch搜索报错ElasticsearchException: failed to map source

1.报错情况，其实es已经有查询结果了，可是却报错了

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.data.elasticsearch.ElasticsearchException: failed to map source [ {"id":1002,"title":"御街行·秋日怀旧","content":"纷纷坠叶飘香砌。夜寂静，寒声碎。真珠帘卷玉楼空，天淡银河垂地。年年今夜，月华如练，长是人千里。"}] to class Article] with root cause

2.解决方法
原因是确实无参构造函数，加上去就好了

 public Article() {
    }