MongoDB Java Inserting Throws org.bson.codecs.conf

Question

I'm learning MongoDB with Java. I'm trying to insert data to MongoDB with Java driver. I'm doing inserting like in MongoDB tutorial and every thing is okey. But if I want to insert a variable and when I run the code, driver throws an error like this:

org.bson.codecs.configuration.CodecConfigurationException: Can't find a codec for class io.github.ilkgunel.mongodb.Pojo.

I searhed questions in Stack Overflow like this but I couldn't understand anything and I cant't find anything to solve this error. My code is below. How can solve this problem?

I'm using this code:

package io.github.ilkgunel.mongodb;
import org.bson.Document;

import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Locale;

public class MongoDBBasicUsage {
    public static void main(String[] args) {
        MongoClient mongoClient;
        try {
            Pojo pojo = new Pojo();
            mongoClient = new MongoClient("localhost", 27017);
            MongoDatabase database = mongoClient.getDatabase("MongoDB");

            pojo.setId("1");
            pojo.setName("ilkay");
            pojo.setSurname("günel");

            Document document = new Document();
            document.put("person", pojo);

            database.getCollection("Records").insertOne(document);  
        } catch (Exception e) {
            System.err.println("Bir Hata Meydana Geldi!");
            System.out.println("Hata" + e);
        }
    }
}

My Pojo is this:

    package io.github.ilkgunel.mongodb;

public class Pojo {
    String name;
    String surname;
    String id;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    } 
}

Answer 1

To be bit abstract, as this may save the day for other developers..
This error: CodecConfigurationException: Can't find a codec for class xxx means that your mongo driver is not able to handle the data you sent in the object you made of that xxx class and accordingly can't generate the mongo query you want.

The resolution in that case would be either to use the right class i.e to use one of the expected classes by the driver (in my case replacing java array by ArrayList object resolved the issue).. The other resolution could be to upgrade your driver. Third solution could be as mentioned by @Renato, to define your own decoding logic.. This depends on your exact case.
hth

Answer 2

From the looks of what you are trying to do, you are trying to add some custom data type (in this case your POJO) but what you need to keep in mind is that fields in documents can only accept certain data types, not objects directly.

In case if you didn't know also, Mongo Documents are structured the same way as json. So you have to explicitaly create the documents by creating the fields and inserting the values into them. There are specific data types that are allowed in value fields:

http://mongodb.github.io/mongo-java-driver/3.0/bson/documents/

To help with your case, the code below takes your POJO as a parameter and knowing the structure of the POJO, returns a Mongo Document that can be inserted into your collection:

private Document pojoToDoc(Pojo pojo){
    Document doc = new Document();

    doc.put("Name",pojo.getName());
    doc.put("Surname",pojo.getSurname());
    doc.put("id",pojo.getId());

    return doc;
} 

This should work for insertion. If you want to index one of the fields:

database.getCollection("Records").createIndex(new Document("id", 1));

I hope this answers your question and works for you.

Answer 3

did you check the library of mongodb. I solve this problem in this morning by change the mongodb java driver from 3.2.2 to 3.4.2. the new maven like that:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-mongodb</artifactId>
    <version>1.5.4.RELEASE</version>
</dependency>

have a try and response

Answer 4

I'm using MongoDB POJO support. In my case, I had this "clue" WARNing before the exception:

 org.bson.codecs.pojo                     : Cannot use 'UserBeta' with the PojoCodec.

org.bson.codecs.configuration.CodecConfigurationException: Property 'premium' in UserBeta, has differing data types: TypeData{type=PremiumStatus} and TypeData{type=Boolean}.

My class UserBeta had getPremium(), setPremium(), and isPremium(). I already @BsonIgnore-d the isPremium() but for some reason it's still detected and causing conflict.

My workaround is to rename isPremium() to isAnyPremium().

Answer 5

You need to configure the CodeRegistry to use the PojoCodecProvider as explained here: http://mongodb.github.io/mongo-java-driver/3.7/driver/getting-started/quick-start-pojo/