注意:请使用mongodbshell执行代码。假设我有一份学生文档，如下所示{"_id":4,"grades":[{"grade":80,"mean":75,"std":8},{"grade":85,"mean":90,"std":5},{"grade":85,"mean":90,"std":5},{"grade":85,"mean":95,"std":6},{"grade":90,"mean":85,"std":5}]}我们有两个问题:问题1:假设您要更新所有子文档_id=4&&grades.grade=85&&grades.std=5，std=6您将编写如下db.students.

如前所述here,AndroidM将不支持ApacheHTTPAPI。文档声明:usetheHttpURLConnectionclassinstead.或TocontinueusingtheApacheHTTPAPIs,youmustfirstdeclarethefollowingcompile-timedependencyinyourbuild.gradlefile:android{useLibrary'org.apache.http.legacy'}我已经将我项目中对HttpClient的大部分使用转换为HttpURLConnection，但是，我仍然需要在一些领域使用HttpCl