Spring Boot Mongo findById returns null

Question

I have a collection, with documents having a field named _id of type String, not generated manually.

I have been trying to get a document using its id.

    val criteria = Criteria.where("_id").`is`("a2z3e44R")
    val document = mongoTemplate.findOne(Query.query(criteria), MyDocument::class.java) // returns null

    val criteria = Criteria.where("_id").`is`(ObjectId("a2z3e44R"))
    val document = mongoTemplate.findOne(Query.query(criteria), MyDocument::class.java) // returns null

    val document = mongoTemplate.findById("a2z3e44R", MyDocument::class.java) // returns null

    mongoTemplate.findAll(MyDocument::class.java).first { myDocument ->
        myDocument._id == "a2z3e44R"
    } // OK...

MyDocument is

data class MyDocument(val _id: String, val name: String)

Trying to find a document by another field works.

An idea of what I could be missing or a workaround?

Can you please post your JSON document the way you get it through mongo.exe or Robo3T? — dnickless, Oct 09 '18 at 19:18

score 2 · Answer 1 · edited Dec 24 '19 at 08:13

2

You should indicate the type of the id like this

public class Article {

    @MongoId(value = FieldType.OBJECT_ID)
    private String id;

    private String title;

    private String desc;
}

edited Dec 24 '19 at 08:13

lczapski

4,026
3
16
32

answered Dec 24 '19 at 07:53

guodong508

21
2

That is a winner answer – Nestor Milyaev Mar 30 '20 at 14:57

score 1 · Answer 2 · answered Oct 09 '18 at 15:36

1

Try mark _id with annotation @Id. The @Id annotation is used to specify the identifier for Spring.

data class MyDocument(@Id val _id: String, val name: String)

answered Oct 09 '18 at 15:36

Matej Marconak

1,365
3
20
25

I implemented your suggestion using `import org.springframework.data.annotation.Id ` but the result remains the same. – Tristan Oct 09 '18 at 15:42
How do you persist new data? – Matej Marconak Oct 09 '18 at 15:46
It is another program taking care of adding data. I am only reading them. – Tristan Oct 09 '18 at 15:47

score 0 · Answer 3 · answered Oct 09 '18 at 15:55

0

Ypu could define in your repository:

public interface MyDocumentRepository extends MongoRepository<MyDocument, String> {
  Pets findBy_id(ObjectId _id);
}

and use it :

myDocumentRepository.findBy_id("a2z3e44R");

for more info see

or

ObjectId objID = new ObjectId("a2z3e44R");
      query.addCriteria(Criteria.where("_id").lt(objID));

like this other answer link

answered Oct 09 '18 at 15:55

Fernix

361
3
10

1

This solution is not working either. This was my initial code. – Tristan Oct 09 '18 at 16:00

Spring Boot Mongo findById returns null

3 Answers3