Spring 引导 findById 不适用于 MongoDB

Question

I'm trying to do a simple get query on springboot using mongodb as database engine

I have tried with several stuff(sending the data as ObjectId and even changing the repository)

public ResponseEntity<Track> get(String trackId) {
    Track find = mongoTemplate.findById(new ObjectId(trackId), Track.class);

    Optional<Track> track = tracksRepository.findById(trackId);

    if (track.isPresent()) {
        return new ResponseEntity<>(track.get(), HttpStatus.OK);
    }

    return new ResponseEntity<>(HttpStatus.NOT_FOUND);

}

with mongo config

@Configuration
@EnableMongoRepositories(basePackages = "data.store.repositories")
public class MongoConfig extends AbstractMongoClientConfiguration {

    private final Logger LOGGER = Logger.getLogger(this.getClass().getSimpleName());

    @Primary
    @Bean
    @Override
    public MongoClient mongoClient() {

        return MongoClients.create(MongoClientSettings.builder()
            .applyToClusterSettings(builder -> builder.hosts(Arrays.asList(new ServerAddress(host, port))))
            .build());
    }

    private MongoCredential mongoCredentials() {
        return MongoCredential.createCredential(username, database, password.toCharArray());
    }

    @Bean
    public MongoTemplate mongoTemplate() {
        MongoTemplate mongoTemplate = new MongoTemplate(mongoClient(), getDatabaseName());
        mongoTemplate.setReadPreference(ReadPreference.secondaryPreferred());
        return mongoTemplate;
    }

    protected String getDatabaseName() {
        return database;
    }

    @Override
    public boolean autoIndexCreation() {
        return false;
    }

}

EDIT: Adding class for context

@Document("track")
public class Track {
    @Id
    @Field(ATTR_ID)
    @JsonProperty(ATTR_ID)
    public String id;
    public static final String ATTR_ID = "id";
}

and getting always null, with existing keys on my database. could you help me find the issue?

Thanks in advance

Answer 1

I tried this with similar configuration class and found the following worked fine creating/accessing data using MongoTemplate .

The POJO class:

public class Test {
    
    @MongoId(FieldType.OBJECT_ID)
    private String id;
    private String name;
    
    public Test() {
    }
    public Test(String s) {
        super();
        this.name = s;
    }
    
    // get, set methods
    
    public String toString( ) {
        return id + " - " + name;
    }
}

From Spring's CommandLineRunner.run() :

    // Insert a document into the database
    Test t1 = new Test("alpha");
    t1 = mt.insert(t1);
    System.out.println(t1); // 61e7de9f5aadc2077d9f4a58 - alpha

    // Query from the database using the _id
    ObjectId id = new ObjectId("61e7de9f5aadc2077d9f4a58");
    Test t2 = mt.findById(id, Test.class);
    System.out.println(t2);

Note that you need to do this from the class where you are running the code:

@Autowired private MongoTemplate mt;

You can use the @MongoId or @Id annotations in our POJO class to represent MongoDB _id field. The type of the field can be a String or ObjectId . It depends upon how you define.

See this from Spring Data MongoDB documentation on How the _id Field is Handled in the Mapping Layer using:

• @MongoId
• @Id

Answer 2

Solution is to add to MongoId annotation field type object id

@MongoId(FieldType.OBJECT_ID)
private String id;