ANANYA7566/hti_training

Creating three microservices specific to Accounts, Loans and Cards by taking a Bank application as an example

Description: This repository has three maven projects with the names accounts, loans, cards. These three projects will acts as a microservices and these are build by taking EazyBank as an example Bank application. Below are the key steps that are followed while creating these projects.

Key steps:

Go to https://start.spring.io/
Fill all the details required to generate a accounts Spring Boot project and add dependencies Spring Web,Spring Boot Actuator,H2 Database, Spring Data JPA , Lombok. Click GENERATE which will download the accounts maven project in a zip format
Repeat the above steps for cards and loans microservices as well.
Extract the downloaded maven projects of accounts, cards, loans and import the same into Eclipse by following the steps mentioned in the course
Visit pom.xml of accounts, cards, loans and make sure all the required dependencies are present in it like shown below,

accounts\pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
  	<groupId>org.springframework.boot</groupId>
  	<artifactId>spring-boot-starter-parent</artifactId>
  	<version>2.4.4</version>
  	<relativePath /> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.eaztbytes</groupId>
  <artifactId>accounts</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>
  <name>accounts</name>
  <description>Microservice for Accounts</description>
  <properties>
  </properties>
  <dependencies>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-actuator</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-web</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>com.h2database</groupId>
  		<artifactId>h2</artifactId>
  		<scope>runtime</scope>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-data-jpa</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-test</artifactId>
  		<scope>test</scope>
  	</dependency>
  	<dependency>
  		<groupId>org.projectlombok</groupId>
  		<artifactId>lombok</artifactId>
  		<scope>provided</scope>
  	</dependency>
  </dependencies>

  <build>
  	<plugins>
  		<plugin>
  			<groupId>org.springframework.boot</groupId>
  			<artifactId>spring-boot-maven-plugin</artifactId>
  		</plugin>
  	</plugins>
  </build>

</project>

loans\pom.xml

 <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <parent>
   	<groupId>org.springframework.boot</groupId>
   	<artifactId>spring-boot-starter-parent</artifactId>
   	<version>2.4.4</version>
   	<relativePath /> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.eaztbytes</groupId>
   <artifactId>loans</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>loans</name>
   <description>Microservice for Loans</description>
   <properties>
   </properties>
   <dependencies>
   	<dependency>
   		<groupId>org.springframework.boot</groupId>
   		<artifactId>spring-boot-starter-actuator</artifactId>
   	</dependency>
   	<dependency>
   		<groupId>org.springframework.boot</groupId>
   		<artifactId>spring-boot-starter-web</artifactId>
   	</dependency>
   	<dependency>
   		<groupId>com.h2database</groupId>
   		<artifactId>h2</artifactId>
   		<scope>runtime</scope>
   	</dependency>
   	<dependency>
   		<groupId>org.springframework.boot</groupId>
   		<artifactId>spring-boot-starter-data-jpa</artifactId>
   	</dependency>
   	<dependency>
   		<groupId>org.springframework.boot</groupId>
   		<artifactId>spring-boot-starter-test</artifactId>
   		<scope>test</scope>
   	</dependency>
   	<dependency>
   		<groupId>org.projectlombok</groupId>
   		<artifactId>lombok</artifactId>
   		<scope>provided</scope>
   	</dependency>
   </dependencies>

   <build>
   	<plugins>
   		<plugin>
   			<groupId>org.springframework.boot</groupId>
   			<artifactId>spring-boot-maven-plugin</artifactId>
   		</plugin>
   	</plugins>
   </build>

</project>

cards\pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
  	<groupId>org.springframework.boot</groupId>
  	<artifactId>spring-boot-starter-parent</artifactId>
  	<version>2.4.4</version>
  	<relativePath /> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.eaztbytes</groupId>
  <artifactId>cards</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>
  <name>cards</name>
  <description>Microservice for Cards</description>
  <properties>
  </properties>
  <dependencies>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-actuator</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-web</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>com.h2database</groupId>
  		<artifactId>h2</artifactId>
  		<scope>runtime</scope>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-data-jpa</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-test</artifactId>
  		<scope>test</scope>
  	</dependency>
  	<dependency>
  		<groupId>org.projectlombok</groupId>
  		<artifactId>lombok</artifactId>
  		<scope>provided</scope>
  	</dependency>
  </dependencies>

  <build>
  	<plugins>
  		<plugin>
  			<groupId>org.springframework.boot</groupId>
  			<artifactId>spring-boot-maven-plugin</artifactId>
  		</plugin>
  	</plugins>
  </build>

</project>

Make sure all the required and associated libraries are downloaded under maven dependencies
Open the application.properties present inside accounts, loans, cards and make sure to update the properties related to H2 database configuration and port as shown below,

\accounts\src\main\resources\application.properties

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

server.port=8080

\loans\src\main\resources\application.properties

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

server.port=8090

\cards\src\main\resources\application.properties

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

server.port=9000

Open the SpringBoot main classes of accounts, loans and cards microservices. We can always identify the main class in a Spring Boot project by looking for the annotation @SpringBootApplication. Below are the sample code present inside these SpringBoot main classes.

\accounts\src\main\java\com\eazybytes\accounts\AccountsApplication.java

package com.eazybytes.accounts;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScans;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@ComponentScans({ @ComponentScan("com.eazybytes.accounts.controller") })
@EnableJpaRepositories("com.eazybytes.accounts.repository")
@EntityScan("com.eazybytes.accounts.model")
public class AccountsApplication {

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

\loans\src\main\java\com\eazybytes\loans\LoansApplication.java

package com.eazybytes.loans;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScans;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@ComponentScans({ @ComponentScan("com.eazybytes.loans.controller") })
@EnableJpaRepositories("com.eazybytes.loans.repository")
@EntityScan("com.eazybytes.loans.model")
public class LoansApplication {

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

}

\cards\src\main\java\com\eazybytes\cards\CardsApplication.java

package com.eazybytes.cards;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScans;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@ComponentScans({ @ComponentScan("com.eazybytes.cards.controller") })
@EnableJpaRepositories("com.eazybytes.cards.repository")
@EntityScan("com.eazybytes.cards.model")
public class CardsApplication {

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

}

Create a new Rest Controller classes like mentioned below for all the three microservices. We can use @GetMapping as well instead of @PostMapping. But I used @PostMapping to make sure any senstive information of Bank customer should not get exposed in the browser URL.

accounts\src\main\java\com\eazybytes\accounts\controller\AccountsController.java

/**
 * 
 */
package com.eazybytes.accounts.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import com.eazybytes.accounts.model.Accounts;
import com.eazybytes.accounts.model.Customer;
import com.eazybytes.accounts.repository.AccountsRepository;

/**
 * @author Eazy Bytes
 *
 */

@RestController
public class AccountsController {
	
	@Autowired
	private AccountsRepository accountsRepository;

	@PostMapping("/myAccount")
	public Accounts getAccountDetails(@RequestBody Customer customer) {

		Accounts accounts = accountsRepository.findByCustomerId(customer.getCustomerId());
		if (accounts != null) {
			return accounts;
		} else {
			return null;
		}

	}

}

\loans\src\main\java\com\eazybytes\loans\controller\LoansController.java

/**
 * 
 */
package com.eazybytes.loans.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import com.eazybytes.loans.model.Customer;
import com.eazybytes.loans.model.Loans;
import com.eazybytes.loans.repository.LoansRepository;

/**
 * @author Eazy Bytes
 *
 */

@RestController
public class LoansController {

	@Autowired
	private LoansRepository loansRepository;

	@PostMapping("/myLoans")
	public List<Loans> getLoansDetails(@RequestBody Customer customer) {
		List<Loans> loans = loansRepository.findByCustomerIdOrderByStartDtDesc(customer.getCustomerId());
		if (loans != null) {
			return loans;
		} else {
			return null;
		}

	}

}

\cards\src\main\java\com\eazybytes\cards\controller\CardsController.java

/**
 * 
 */
package com.eazybytes.cards.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import com.eazybytes.cards.model.Cards;
import com.eazybytes.cards.model.Customer;
import com.eazybytes.cards.repository.CardsRepository;

/**
 * @author Eazy Bytes
 *
 */

@RestController
public class CardsController {

	@Autowired
	private CardsRepository cardsRepository;

	@PostMapping("/myCards")
	public List<Cards> getCardDetails(@RequestBody Customer customer) {
		List<Cards> cards = cardsRepository.findByCustomerId(customer.getCustomerId());
		if (cards != null) {
			return cards;
		} else {
			return null;
		}

	}

}

Make sure that all the dependent Entity Java files & JPA Repository files are present inside the three projects like shown below,

accounts\src\main\java\com\eazybytes\accounts\model\Accounts.java

package com.eazybytes.accounts.model;

import java.time.LocalDate;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

@Entity
@Getter @Setter @ToString
public class Accounts {

	@Column(name = "customer_id")
	private int customerId;
	@Column(name="account_number")
	@Id
	private long accountNumber;
	@Column(name="account_type")
	private String accountType;
	@Column(name = "branch_address")
	private String branchAddress;
	@Column(name = "create_dt")
	private LocalDate createDt;
	
}

\accounts\src\main\java\com\eazybytes\accounts\model\Customer.java

package com.eazybytes.accounts.model;

import java.time.LocalDate;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

@Entity
@Getter @Setter @ToString
public class Customer {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name = "customer_id")
	private int customerId;
	private String name;
	private String email;
	@Column(name = "mobile_number")
	private String mobileNumber;
	@Column(name = "create_dt")
	private LocalDate createDt;

}

\accounts\src\main\java\com\eazybytes\accounts\repository\AccountsRepository.java

package com.eazybytes.accounts.repository;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import com.eazybytes.accounts.model.Accounts;

@Repository
public interface AccountsRepository extends CrudRepository<Accounts, Long> {

	Accounts findByCustomerId(int customerId);

}

\loans\src\main\java\com\eazybytes\loans\model\Loans.java

package com.eazybytes.loans.model;

import java.sql.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

@Entity
@Getter @Setter @ToString
public class Loans {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name = "loan_number")
	private int loanNumber;
	
	@Column(name = "customer_id")
	private int customerId;
	
	@Column(name="start_dt")
	private Date startDt;
	
	@Column(name = "loan_type")
	private String loanType;
	
	@Column(name = "total_loan")
	private int totalLoan;
	
	@Column(name = "amount_paid")
	private int amountPaid;
	
	@Column(name = "outstanding_amount")
	private int outstandingAmount;
	
	@Column(name = "create_dt")
	private String createDt;
	
}

\loans\src\main\java\com\eazybytes\loans\model\Customer.java

package com.eazybytes.loans.model;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;


@Getter @Setter @ToString
public class Customer {

	private int customerId;

}

\loans\src\main\java\com\eazybytes\loans\repository\LoansRepository.java

package com.eazybytes.loans.repository;

import java.util.List;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import com.eazybytes.loans.model.Loans;

@Repository
public interface LoansRepository extends CrudRepository<Loans, Long> {

	
	List<Loans> findByCustomerIdOrderByStartDtDesc(int customerId);

}

\cards\src\main\java\com\eazybytes\cards\model\Cards.java

package com.eazybytes.cards.model;

import java.sql.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

@Entity
@Getter
@Setter
@ToString
public class Cards {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name = "card_id")
	private int cardId;

	@Column(name = "customer_id")
	private int customerId;

	@Column(name = "card_number")
	private String cardNumber;

	@Column(name = "card_type")
	private String cardType;

	@Column(name = "total_limit")
	private int totalLimit;

	@Column(name = "amount_used")
	private int amountUsed;

	@Column(name = "available_amount")
	private int availableAmount;

	@Column(name = "create_dt")
	private Date createDt;

}

\cards\src\main\java\com\eazybytes\cards\model\Customer.java

package com.eazybytes.cards.model;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;


@Getter @Setter @ToString
public class Customer {

	private int customerId;

}

\cards\src\main\java\com\eazybytes\cards\repository\CardsRepository.java

package com.eazybytes.cards.repository;

import java.util.List;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import com.eazybytes.cards.model.Cards;

@Repository
public interface CardsRepository extends CrudRepository<Cards, Long> {

	
	List<Cards> findByCustomerId(int customerId);

}

To set up tables, columns, data needed inside the H2 database, create a data.sql file in all the microservices under src\main\resources\ folder. Below are the sample SQL scripts for each microservice. Please note that these scripts will be executed everytime you start the microservice and the moment you stop/restart your service all your data present inside your H2 database will be lost. So please make sure not to use internal memory H2 database inside production applications.

\accounts\src\main\resources\data.sql

DROP TABLE IF EXISTS customer;
DROP TABLE IF EXISTS accounts;

CREATE TABLE `customer` (
  `customer_id` int AUTO_INCREMENT  PRIMARY KEY,
  `name` varchar(100) NOT NULL,
  `email` varchar(100) NOT NULL,
  `mobile_number` varchar(20) NOT NULL,
  `create_dt` date DEFAULT NULL
);

CREATE TABLE `accounts` (
  `customer_id` int NOT NULL,
   `account_number` int AUTO_INCREMENT  PRIMARY KEY,
  `account_type` varchar(100) NOT NULL,
  `branch_address` varchar(200) NOT NULL,
  `create_dt` date DEFAULT NULL
);

INSERT INTO `customer` (`name`,`email`,`mobile_number`,`create_dt`)
 VALUES ('Eazy Bytes','tutor@eazybytes.com','9876548337',CURDATE());
 
INSERT INTO `accounts` (`customer_id`, `account_number`, `account_type`, `branch_address`, `create_dt`)
 VALUES (1, 186576453, 'Savings', '123 Main Street, New York', CURDATE());

\loans\src\main\resources\data.sql

DROP TABLE IF EXISTS loans;

CREATE TABLE `loans` (
  `loan_number` int NOT NULL AUTO_INCREMENT,
  `customer_id` int NOT NULL,
  `start_dt` date NOT NULL,
  `loan_type` varchar(100) NOT NULL,
  `total_loan` int NOT NULL,
  `amount_paid` int NOT NULL,
  `outstanding_amount` int NOT NULL,
  `create_dt` date DEFAULT NULL,
  PRIMARY KEY (`loan_number`)
);

INSERT INTO `loans` ( `customer_id`, `start_dt`, `loan_type`, `total_loan`, `amount_paid`, `outstanding_amount`, `create_dt`)
 VALUES ( 1, '2020-10-13', 'Home', 200000, 50000, 150000, '2020-10-13');
 
INSERT INTO `loans` ( `customer_id`, `start_dt`, `loan_type`, `total_loan`, `amount_paid`, `outstanding_amount`, `create_dt`)
 VALUES ( 1, '2020-06-06', 'Vehicle', 40000, 10000, 30000, '2020-06-06');
 
INSERT INTO `loans` ( `customer_id`, `start_dt`, `loan_type`, `total_loan`, `amount_paid`, `outstanding_amount`, `create_dt`)
 VALUES ( 1, '2021-02-14', 'Home', 50000, 10000, 40000, '2018-02-14');

INSERT INTO `loans` ( `customer_id`, `start_dt`, `loan_type`, `total_loan`, `amount_paid`, `outstanding_amount`, `create_dt`)
 VALUES ( 1, '2018-02-14', 'Personal', 10000, 3500, 6500, '2018-02-14');

\cards\src\main\resources\data.sql

DROP TABLE IF EXISTS cards;

CREATE TABLE `cards` (
  `card_id` int NOT NULL AUTO_INCREMENT,
  `card_number` varchar(100) NOT NULL,
  `customer_id` int NOT NULL,
  `card_type` varchar(100) NOT NULL,
  `total_limit` int NOT NULL,
  `amount_used` int NOT NULL,
  `available_amount` int NOT NULL,
  `create_dt` date DEFAULT NULL,
  PRIMARY KEY (`card_id`)
);


INSERT INTO `cards` (`card_number`, `customer_id`, `card_type`, `total_limit`, `amount_used`, `available_amount`, `create_dt`)
 VALUES ('4565XXXX4656', 1, 'Credit', 10000, 500, 9500, CURDATE());

INSERT INTO `cards` (`card_number`, `customer_id`, `card_type`, `total_limit`, `amount_used`, `available_amount`, `create_dt`)
 VALUES ('3455XXXX8673', 1, 'Credit', 7500, 600, 6900, CURDATE());
 
INSERT INTO `cards` (`card_number`, `customer_id`, `card_type`, `total_limit`, `amount_used`, `available_amount`, `create_dt`)
 VALUES ('2359XXXX9346', 1, 'Credit', 20000, 4000, 16000, CURDATE());

Go to your Spring Boot main classes and start all the three microservices by right click-> Run As -> Java Application. This will start your microservices successfully at port 8080,8090,9000 based on the ports configured inside application.properties. Your can confirm the same by looking at the console logs.
Access the URLs of H2 databases of all the three microservices to make sure tables, columns, data is created inside them successfully. The URLs are http://localhost:8080/h2- console/, http://localhost:8090/h2-console/, http://localhost:9000/h2-console/ respectively.
Invoke the REST APIs http://localhost:8080/myAccount, http://localhost:8090/myLoans, http://localhost:9000/myCards through Postman by passing the below request in JSON format. You should get the response from the corresponding microservices.

{
    "customerId": 1
}

ANANYA7566 / hti_training