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Type:
Task
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Resolution: Works as Designed
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Priority:
Unknown
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None
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Affects Version/s: None
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Component/s: POJO
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Not Needed
I have a Test object that have an embedded class SubTest.
public class Test { public String field; public String unwanted; public SubTest subtest; public static class SubTest { public String subField; public String subUnwanted; } }
And a projection class that I want to use with a projected query.
public class TestProjection { public String field; @BsonProperty("subtest.subField") public String subField; }
When I try to list all the document with a projection query that contains the fields "field" and "subtest.subField", the query succeed but the subField field is null.
See the following example code snippet:
MongoClient mongoClient = MongoClients.create(); PojoCodecProvider pojoCodecProvider = PojoCodecProvider.builder().automatic(true).build(); CodecRegistry pojoCodecRegistry = fromRegistries(getDefaultCodecRegistry(), fromProviders(pojoCodecProvider)); MongoDatabase database = mongoClient.getDatabase("test").withCodecRegistry(pojoCodecRegistry); MongoCollection<Test> collection = database.getCollection("test", Test.class); Test test = new Test(); test.field = "field"; test.unwanted = "unwanted"; Test.SubTest subTest = new Test.SubTest(); subTest.subField = "subField"; subTest.subUnwanted = "subUwanted"; test.subtest = subTest; System.out.println("Inserting the element"); collection.insertOne(test); System.out.println("Listing all elements"); collection.find().cursor().forEachRemaining(System.out::println); System.out.println("Listing all elements with a projection"); MongoCollection<TestProjection> projectedCollection = collection.withDocumentClass(TestProjection.class); projectedCollection.find() .projection(Projections.include("field", "subtest.subField")) .cursor() .forEachRemaining(System.out::println); ///here subtest.subField is null but should not be