Mongodb – ConfigurationProperties read on startup, but show null when Bean accessed

Storing all my Mongo properties in an external application.properties files and reading them with the provided classes. I’m using them in a bean to build DatabaseFactory objects, but they read null when the bean is accessed – even after reading properly at startup.

MongoProperties.java

package com.mistermorse.flawlessbeansjavaspringapi.config;

import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "spring.data.mongodb")
public class MongoProperties {

    private String uri;
    private String database;
   
    public String getUri() {
        return uri;
    }

    public void setUri(String uri) {
        this.uri = uri;
    }

    public String getDatabase() {
        return database;
    }

    public void setDatabase(String database) {
        this.database = database;
    }

}

MongoApplication.java

package com.mistermorse.flawlessbeansjavaspringapi;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.ConfigurationPropertiesScan;

@SpringBootApplication
@ConfigurationPropertiesScan("com.mistermorse.flawlessbeansjavaspringapi")
public class FlawlessBeansJavaSpringApiApplication {

    public static void main(String[] args) {
        SpringApplication.run(FlawlessBeansJavaSpringApiApplication.class, args);
    }

}

So, I’m working on user functionality right now, but I made a temporary endpoint to check the property logic, and I’m having trouble using a bean to create a factory.

UserController.java

package com.mistermorse.flawlessbeansjavaspringapi.controller;

import com.mistermorse.flawlessbeansjavaspringapi.config.MongoGeneral;
import com.mistermorse.flawlessbeansjavaspringapi.config.MongoProperties;
import com.mongodb.client.MongoIterable;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@EnableConfigurationProperties(MongoProperties.class)
@RestController
@RequestMapping("/user")
public class UserController {

    private ApplicationContext applicationContext;
    private MongoProperties mongoProperties;

    @Autowired
    public UserController(MongoProperties mongoProperties) {
        this.applicationContext = new AnnotationConfigApplicationContext();
        this.mongoProperties = mongoProperties;
    }

    @GetMapping("/collections")
    public MongoIterable<String> getCollections() {
        ApplicationContext applicationContext = new AnnotationConfigApplicationContext(MongoGeneral.class);
        SimpleMongoClientDatabaseFactory simpleMongoClientDatabaseFactory = applicationContext.getBean("mongoDbFactory",SimpleMongoClientDatabaseFactory.class);
        return simpleMongoClientDatabaseFactory.getMongoDatabase("db").listCollectionNames();
    }

}

Now, here’s the problem; I have a config file with a bean method to return a SimpleMongoClientDatabaseFactory using MongoClients.create() and a URI; at first, I tested it with the direct address containing u/p. It worked. Now, I’m trying to use the ConfigurationProperties.

MongoGeneral.java

package com.mistermorse.flawlessbeansjavaspringapi.config;

import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.lang.NonNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.config.AbstractMongoClientConfiguration;
import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;

@Configuration
@EnableConfigurationProperties(MongoProperties.class)
public class MongoGeneral extends AbstractMongoClientConfiguration {

    private MongoProperties mongoProperties;

    @Autowired
    public MongoGeneral(MongoProperties mongoProperties) {
        this.mongoProperties = mongoProperties;
    }

    @Override
    @NonNull
    public String getDatabaseName() {
        System.out.println("Name: " + this.mongoProperties.getDatabase());
        return this.mongoProperties.getDatabase();
    }

    @Override
    @NonNull
    public MongoClient mongoClient() {
        return MongoClients.create("mongodb+srv://matthewharp:[email protected]/?retryWrites=true&w=majority&appName=Cluster0");
    }

    @Bean
    @NonNull
    @Override
    public SimpleMongoClientDatabaseFactory mongoDbFactory() {
        return new SimpleMongoClientDatabaseFactory(mongoClient(), getDatabaseName());
    }

}

Here’s the problem: when the app starts, the log in getDatabase() dumps out the correct property value, whether I have the hard-coded value or the property, AND the factory gets made if the hard-coded value is used when the bean method is called.

However, the value is only correct if hard-coded when the bean is accessed during the controller call; the property value is null otherwise, and the factory creation fails.

I’ve even tried to attach property values to member fields in MongoGeneral.java in the constructor, but it still shows null when accessed via the controller. Can anyone see, and help with, what I’m doing wrong?