提取时对集合中的文档进行排序 [英] Sort documents in collections while fetching
问题描述
我在MongoDB上有一个名为resource的集合. 它具有以下文档:
I have a collection called at MongoDB called resource. It has the following documents:
{ "_id" : "Abb.e", "_class" : "Resource", "resourceEmail" : "test1@test.com" }
{ "_id" : "Dasd.tt", "_class" : "Resource","resourceEmail" : "test2@test.com" }
{ "_id" : "Bbb.rr", "_class" : "Resource", "resourceEmail" : "test3@test.com" }
在Java代码中，我将它们列出如下:
At Java code,I list them as follows:
MongoOperations mongoOperations = mongoConfiguration.getMongoTemplate();
List<Resource> resourceList = mongoOperations.findAll(Resource.class);
return resourceList;
如何获取按ID排序的这些文档！
How could I fetch these documents sorted by ID !
推荐答案
在使用Spring Data时，您可以使用Query对象查询集合中的所有文档并对结果进行排序.
As you're using Spring Data, you could use a Query object to query all documents in the colletion and sort the results.
MongoOperations mongoOperations = mongoConfiguration.getMongoTemplate();
Query q = new Query().with(new Sort(Sort.Direction.ASC, "_id"));
List<Resource> resourceList = mongoOperations.find(q, Resource.class);
return resourceList;
当然，您可以迭代结果列表并对其进行手动排序，甚至可以使用Collection.sort方法，但是我认为，如果在用于排序的属性中有一个索引，则对mongodb sort进行排序会更快结果.
Of course that you could iterate the list of results and sort it manually, or even use Collection.sort method, but I think if you have an index in the property that you're using to sort, it's faster to mongodb sort the results.
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