春季数据mongodb group by

将您的

TypedAggregation

students

StudentResults

 TypedAggregation<Student> studentAggregation = Aggregation.newAggregation(Student.class,    Aggregation.group("firstName").    push("$$ROOT").as("students"));

$$ ROOT将推送整个文档。

更新：

TypedAggregation<Student> studentAggregation = Aggregation.newAggregation(Student.class,   Aggregation.group("firstName").      push(new BasicDBObject ("_id", "$_id").append ("firstName", "$firstName").append ("lastName", "$lastName")).as("students"));