MongoDB 的 Morphia、Mongo4j 和 Spring 数据如何比较 [关闭]

MongoDB是一个流行的NoSQL数据库，它提供了Morphia、Mongo4j和Spring Data这三种不同的访问方式。本文将对这三种方式进行比较，并通过案例代码来说明它们的使用。

java
@Entity("users")
public class User {
    @Id
    private ObjectId id;
    private String name;
    private int age;
    // 省略其他属性和方法
}
public class UserRepository {
    private Datastore datastore;
    public UserRepository() {
        Morphia morphia = new Morphia();
        datastore = morphia.createDatastore(new MongoClient(), "mydatabase");
    }
    public void saveUser(User user) {
        datastore.save(user);
    }
    public List findAllUsers() {
        Query query = datastore.createQuery(User.class);
        return query.asList();
    }
}
public class Main {
    public static void main(String[] args) {
        UserRepository userRepository = new UserRepository();
        User user = new User();
        user.setName("John");
        user.setAge(25);
        userRepository.saveUser(user);
        List users = userRepository.findAllUsers();
        for (User u : users) {
            System.out.println(u.getName() + ", " + u.getAge());
        }
    }
}

java
public class Main {
    public static void main(String[] args) {
        MongoClient client = new MongoClient();
        MongoDatabase database = client.getDatabase("mydatabase");
        MongoCollection collection = database.getCollection("users");
        Document user = new Document("name", "John")
                .append("age", 25);
        collection.insertOne(user);
        FindIterable iterable = collection.find();
        for (Document doc : iterable) {
            String name = doc.getString("name");
            int age = doc.getInteger("age");
            System.out.println(name + ", " + age);
        }
    }
}

java
public interface UserRepository extends MongoRepository {
    List findByAge(int age);
}
public class Main {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = 
                new AnnotationConfigApplicationContext(AppConfig.class);
        UserRepository userRepository = context.getBean(UserRepository.class);
        User user = new User();
        user.setName("John");
        user.setAge(25);
        userRepository.save(user);
        List users = userRepository.findByAge(25);
        for (User u : users) {
            System.out.println(u.getName() + ", " + u.getAge());
        }
    }
}