Directory Structure

.
├── main
│  ├── java
│  │  └── com
│  │  └── forhadmethun
│  │  └── accountservice
│  │  ├── config
│  │  │  └── RabbitMQConfiguration.java
│  │  ├── controller
│  │  │  ├── AccountController.java
│  │  │  ├── ExceptionController.java
│  │  │  ├── HealthController.java
│  │  │  └── TransactionController.java
│  │  ├── db
│  │  │  ├── entity
│  │  │  │  ├── Account.java
│  │  │  │  ├── Balance.java
│  │  │  │  ├── Customer.java
│  │  │  │  └── Transaction.java
│  │  │  ├── repository
│  │  │  │  ├── AccountCommandRepository.java
│  │  │  │  ├── AccountQueryRepository.java
│  │  │  │  ├── BalanceCommandRepository.java
│  │  │  │  ├── BalanceQueryRepository.java
│  │  │  │  ├── CustomerRepository.java
│  │  │  │  ├── TransactionQueryRepository.java
│  │  │  │  └── TransactionRepository.java
│  │  │  └── services
│  │  │  ├── AccountService.java
│  │  │  ├── BalanceService.java
│  │  │  ├── bean
│  │  │  │  ├── AccountServiceBean.java
│  │  │  │  ├── BalanceServiceBean.java
│  │  │  │  ├── CustomerServiceBean.java
│  │  │  │  ├── MessageQueueBean.java
│  │  │  │  └── TransactionServiceBean.java
│  │  │  ├── CustomerService.java
│  │  │  ├── MessageQueueService.java
│  │  │  └── TransactionService.java
│  │  ├── MbankAccountServiceApplication.java
│  │  └── utility
│  │  ├── constant
│  │  │  └── PersistenceConstant.java
│  │  ├── CurrencyUtil.java
│  │  ├── dto
│  │  │  ├── mapper
│  │  │  │  ├── AccountMapper.java
│  │  │  │  ├── BalanceMapper.java
│  │  │  │  ├── CustomerMapper.java
│  │  │  │  └── TransactionMapper.java
│  │  │  └── model
│  │  │  ├── AccountDto.java
│  │  │  ├── BalanceDto.java
│  │  │  ├── CustomerDto.java
│  │  │  ├── DirectionOfTransaction.java
│  │  │  ├── mq
│  │  │  │  └── BalanceMQDto.java
│  │  │  └── TransactionDto.java
│  │  ├── exception
│  │  │  ├── PersistenceException.java
│  │  │  └── RequestException.java
│  │  ├── io
│  │  │  ├── AccountOperationResponse.java
│  │  │  ├── ErrorResponse.java
│  │  │  └── mq
│  │  │  ├── AccountCreationInfo.java
│  │  │  └── TransactionCreationInfo.java
│  │  ├── TransactionUtil.java
│  │  └── validation
│  │  ├── AccountServiceValidation.java
│  │  ├── ValidationImpl.java
│  │  ├── Validation.java
│  │  └── ValidationResult.java
│  └── resources
│  ├── application.properties
│  ├── db
│  │  └── migration
│  │  └── V1__create_table.sql
│  ├── static
│  └── templates
└── test
 └── java
 └── com
 └── forhadmethun
 └── accountservice
 ├── controller
 │  ├── AccountControllerTest.java
 │  └── TransactionControllerTest.java
 └── MbankAccountServiceApplicationTests.java

Some of the Code(Please see the Github repo for all the files)

AccountController.java

package com.forhadmethun.accountservice.controller;
/**
 * @author Md Forhad Hossain
 * @since 01/10/20
 */
import com.forhadmethun.accountservice.db.services.AccountService;
import com.forhadmethun.accountservice.db.services.CustomerService;
import com.forhadmethun.accountservice.utility.CurrencyUtil;
import com.forhadmethun.accountservice.utility.dto.model.CustomerDto;
import com.forhadmethun.accountservice.utility.exception.PersistenceException;
import com.forhadmethun.accountservice.utility.exception.RequestException;
import com.forhadmethun.accountservice.utility.io.AccountOperationResponse;
import lombok.AllArgsConstructor;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
@RestController
@AllArgsConstructor
public class AccountController {
 private final CustomerService customerService;
 private final AccountService accountService;
 @PostMapping("/accounts")
 public ResponseEntity<AccountOperationResponse> createAccount(
 @RequestBody CustomerDto customerDto
 ) throws RequestException {
 CurrencyUtil.checkCurrencyValidity(customerDto.getCurrencies());
 AccountOperationResponse accountCreationResponse =
 customerService.createCustomer(customerDto);
 return new ResponseEntity<>(accountCreationResponse, HttpStatus.OK);
 }
 @GetMapping("/accounts/{accountId}")
 public ResponseEntity<AccountOperationResponse> getAccount(
 @PathVariable Long accountId
 ) throws PersistenceException {
 AccountOperationResponse accountOperationResponse =
 accountService.findByAccountId(accountId);
 return new ResponseEntity<>(accountOperationResponse, HttpStatus.OK);
 }
}

AccountServiceBean.java

package com.forhadmethun.accountservice.db.services.bean;
/**
 * @author Md Forhad Hossain
 * @since 01/10/20
 */
import com.forhadmethun.accountservice.db.entity.Account;
import com.forhadmethun.accountservice.db.entity.Balance;
import com.forhadmethun.accountservice.db.repository.AccountQueryRepository;
import com.forhadmethun.accountservice.db.repository.AccountCommandRepository;
import com.forhadmethun.accountservice.db.repository.BalanceQueryRepository;
import com.forhadmethun.accountservice.db.services.AccountService;
import com.forhadmethun.accountservice.db.services.BalanceService;
import com.forhadmethun.accountservice.utility.constant.PersistenceConstant;
import com.forhadmethun.accountservice.utility.dto.mapper.BalanceMapper;
import com.forhadmethun.accountservice.utility.dto.model.AccountDto;
import com.forhadmethun.accountservice.utility.exception.PersistenceException;
import com.forhadmethun.accountservice.utility.io.AccountOperationResponse;
import lombok.AllArgsConstructor;
import org.springframework.stereotype.Service;
import java.util.List;
@AllArgsConstructor
@Service
public class AccountServiceBean implements AccountService {
 private final AccountCommandRepository accountCommandRepository;
 private final AccountQueryRepository accountQueryRepository;
 private final BalanceService balanceService;
 @Override
 public Account createAccount(Account account) {
 return accountCommandRepository.save(account);
 }
 @Override
 public AccountOperationResponse findByAccountId(Long accountId) throws PersistenceException {
 AccountDto account = accountQueryRepository.findByAccountId(accountId);
 if (account == null)
 throw new PersistenceException(PersistenceConstant.ACCOUNT_NOT_FOUND);
 List<Balance> balances = balanceService.findByAccountId(accountId);
 AccountOperationResponse accountOperationResponse =
 AccountOperationResponse.createAccountCreationResponse(
 account.getAccountId(),
 account.getCustomerId(),
 BalanceMapper.toBalanceDtoList(balances)
 );
 return accountOperationResponse;
 }
}

AccountControllerTest.java

package com.forhadmethun.accountservice.controller;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.forhadmethun.accountservice.db.services.CustomerService;
import com.forhadmethun.accountservice.utility.dto.model.CustomerDto;
import com.forhadmethun.accountservice.utility.io.AccountOperationResponse;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit.jupiter.SpringExtension;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.MvcResult;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import java.math.BigDecimal;
import java.util.Arrays;
import static org.hamcrest.Matchers.*;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.junit.jupiter.api.Assertions.*;
@ExtendWith(SpringExtension.class)
@SpringBootTest
@AutoConfigureMockMvc
class AccountControllerTest {
 @Autowired
 CustomerService customerService;
 @Autowired
 private MockMvc mockMvc;
 @Autowired
 private ObjectMapper objectMapper;
 @Test
 void createAccount() throws Exception {
 MvcResult mockMvcResult = mockMvc.perform(MockMvcRequestBuilders
 .post("/accounts", 42L)
 .contentType("application/json")
 .content(objectMapper.writeValueAsString(
 CustomerDto.builder()
 .customerId(1L)
 .country("Bangladesh")
 .currencies(Arrays.asList("EUR"))
 .build()
 )))
 .andExpect(status().isOk())
 .andReturn();
 String contentAsString = mockMvcResult.getResponse().getContentAsString();
 AccountOperationResponse response = objectMapper.readValue(contentAsString, AccountOperationResponse.class);
 assertEquals(1L, response.getCustomerId());
 assertEquals(1, response.getBalances().size());
 assertEquals("EUR", response.getBalances().get(0).getCurrency());
 assertEquals(BigDecimal.ZERO, response.getBalances().get(0).getBalance());
 }
 @Test
 void getAccount() throws Exception {
 AccountOperationResponse createdAccountObject =
 customerService.createCustomer(
 CustomerDto.builder()
 .customerId(36L)
 .country("Bangladesh")
 .currencies(Arrays.asList("EUR"))
 .build()
 );
 MvcResult mockMvcResult =
 mockMvc.perform(get("/accounts/" + createdAccountObject.getAccountId()))
 .andExpect(content().contentType(MediaType.APPLICATION_JSON))
 .andExpect(status().isOk())
 .andExpect(jsonPath("$.balances[0].currency", is("EUR"))
 ).andReturn();
 String contentAsString = mockMvcResult.getResponse().getContentAsString();
 AccountOperationResponse response = objectMapper.readValue(contentAsString, AccountOperationResponse.class);
 assertEquals(response.getAccountId(), createdAccountObject.getAccountId());
 assertEquals(response.getCustomerId(), createdAccountObject.getCustomerId());
 assertEquals(response.getBalances().size(), createdAccountObject.getBalances().size());
 assertEquals("EUR", response.getBalances().get(0).getCurrency());
 }
}

I wrote two microservices in Springboot and tried to follow the best practices. I would appreciate any suggestions about any improvement that I can make on the whole codebase.

https://github.com/forhadmethun/mbank

Technology used:

Java 11+
SpringBoot
JPA / Hibernate
MyBatis
Gradle
Postgres
RabbitMQ
JUnit

Thank you very much.

I wrote two microservices in Springboot and tried to follow the best practices. I would appreciate any suggestions about any improvement that I can make on the whole codebase. What are the parts of the code that I can improve on the whole project?

Project Link: https://github.com/forhadmethun/mbank

Technology used:

Java 11+
SpringBoot
JPA / Hibernate
MyBatis
Gradle
Postgres
RabbitMQ
JUnit

Thank you very much.