paulasanchez810 / ieti-spring-boot-data

Spring Boot Data with MongoDB

Learning Objectives

• Explain what MongoDB is.
• Explain the difference between SQL and NoSQL.
• Create a MongoDB Cluster on Atlas.
• Connect your Spring Boot project with a MongoDB Cluster.

Detail Orientation 🤹🏽

Read the following document Attention to details

Main Topics

• NoSQL.
• MongoDB.
• Cluster.

Codelab 🧪

🗣️ "I hear and I forget I see and I remember I do and I understand." Confucius

Part 1: Creating your Atlas account and first cluster:

If you haven't created your MongoDB Cluster follow part 1 - 4:

• Get Started with Atlas

Part 2: Connecting my MongoDB Cluster with Spring Boot

1. Login into your MongoDB Atlas account

2. Click connect on the cluster you created on Part 1:

3. Select Connect your application:

4. Choose the Java driver, select the latest version and copy the connection string:

5. Replace the password on the connection string with the password used when creating your database user.

6. Add an Environment Variable to the application.properties file to store the MongoDB URI:

   spring.data.mongodb.uri=${MONGODB_URI}

7. Add the environment variable to IntelliJ Idea by editing the Run/Debug Configurations:

   

8. Add the Spring Boot starter data MongoDB dependency to your build.gradle:

      dependencies {
           implementation 'org.springframework.boot:spring-boot-starter-web'
           implementation 'org.springframework.boot:spring-boot-starter-data-mongodb'
           testImplementation 'org.springframework.boot:spring-boot-starter-test'
       }

9. Run your project and verify that the connection is successful.

Part 3: Implementing the MongoDB Service

1. Create a new package called repository.

2. Create a new class called UserDocument:

   Java:

     import org.springframework.data.annotation.Id;
     import org.springframework.data.mongodb.core.index.Indexed;
     import org.springframework.data.mongodb.core.mapping.Document;
     
     import java.util.Date;
     
     @Document
     public class UserDocument
     {
        @Id
        String id;
     
        String name;
     
        @Indexed( unique = true )
        String email;
     
        String lastName;
     
        Date createdAt;
     
        public UserDocument()
        {
        }
     }

   Kotlin:

       @Document
       class User(
          @Id var id: String?,
          var name: String,
          var lastName: String,
          @Indexed(unique = true)
          var email: String,
          var createdAt: Date
       )

3. Create a new interface called UserRepository inside the repository package:

   Java:

     import org.springframework.data.mongodb.repository.MongoRepository;
     
     public interface UserRepository extends MongoRepository<UserDocument, String>
     {}

   Kotlin:

       interface UserRepository: MongoRepository<UserDocument, String>

4. Create a new UserService implementation called UserServiceMongoDB and inject inside the UserRepository:

   Java:

      import java.util.List;
      
      public class UserServiceMongoDB
      implements UserService
      {
      
          private final UserRepository userRepository;
      
          public UserServiceMongoDB(@Autowired UserRepository userRepository )
          {
              this.userRepository = userRepository;
          }
      
          @Override
          public User create( User user )
          {
              return null;
          }
      
          @Override
          public User findById( String id )
          {
              return null;
          }
      
          @Override
          public List<User> all()
          {
              return null;
          }
      
          @Override
          public boolean deleteById( String id )
          {
              return false;
          }
      
          @Override
          public User update( UserDto userDto, String id )
          {
              return null;
          }
      }

   Kotlin:

       class UserServiceMongoDB(@Autowired private val userRepository: UserRepository) : UserService {
       override fun create(user: User): User? {
       return null
       }
       
           override fun findById(id: String): User? {
               return null
           }
       
           override fun all(): List<User>? {
               return null
           }
       
           override fun deleteById(id: String): Boolean {
               return false
           }
       
           override fun update(userDto: UserDto, id: String): User? {
               return null
           }
       }         

5. Implement the methods of the UserServiceMongoDB using the UserRepository.

6. Remove the @Service annotation from the UserServiceHashMap and add it to the UserServiceMongoDB.

7. Test your API and verify that your data is stored in your cluster.

Challenge Yourself: Implement complex queries using the Spring Data Query Methods

1. Modify the UserService interface adding the following methods:

   Java:

       List<User> findUsersWithNameOrLastNameLike(String queryText);
       
       List<User> findUsersCreatedAfter(Date startDate);
     {}

   Kotlin:

      fun findUsersWithNameOrLastNameLike(queryText: String): List<User>
      
      fun findUsersCreatedAfter(startDate: Date): List<User>

Tip: take a look at the official documenation and learn how to create custom queries with Spring Data