naren-jha / DemoApp

Spring boot CRUD demo app with PostgreSQL and MySQL

DemoApp

• https://youtu.be/9SGDpanrc8U
• JUnit: https://youtu.be/Geq60OVyBPg?t=1479
• assertj: https://www.baeldung.com/introduction-to-assertj

Database configs

PostgreSQL config

spring:
  datasource:
    url: jdbc:postgresql://localhost:5432/student
    username:
    password:
  jpa:
    hibernate:
      ddl-auto: 'create-drop'
    show-sql: true
    properties:
      hibernate:
        dialect: org.hibernate.dialect.PostgreSQLDialect
        format_sql: true

MySql config

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/student
    username: root
    password: root1234
  jpa:
    hibernate:
      ddl-auto: 'create-drop'
    show-sql: true

Also, replace postgresql dependency with mysql dependency when changing the database

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
</dependency>

Curl

Create:

curl --location --request POST 'localhost:8080/api/v1/student/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "name": "Joe Goldberg",
    "email": "[e-mail]",
    "age": 25,
    "dob": "2001-06-20"
}'

Get:

curl --location --request GET 'localhost:8080/api/v1/student/'

curl --location --request GET 'localhost:8080/api/v1/student/1'

Update:

curl --location --request PUT 'localhost:8080/api/v1/student/2?name=Joe&email=[e-mail]' \
--header 'Content-Type: application/json' \
--data-raw ''

Delete:

curl --location --request DELETE 'localhost:8080/api/v1/student/1' \
--data-raw ''

Run multiple instances of the app

cd target

java -jar demo-0.0.1-SNAPSHOT.jar on default port 8080

java -jar demo-0.0.1-SNAPSHOT.jar --server.port=8081

java -jar demo-0.0.1-SNAPSHOT.jar --server.port=8082

Using RestTemplate

Synchronous client to perform HTTP requests, exposing a simple, template method API over underlying HTTP client libraries such as the JDK HttpURLConnection, Apache HttpComponents, and others.

• https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/client/RestTemplate.html
• https://howtodoinjava.com/spring-boot2/resttemplate/spring-restful-client-resttemplate-example/
• https://www.baeldung.com/rest-template

Using WebClient

Non-blocking, reactive client to perform HTTP requests, exposing a fluent, reactive API over underlying HTTP client libraries such as Reactor Netty.

• https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/reactive/function/client/WebClient.html
• https://www.baeldung.com/spring-5-webclient
• https://reflectoring.io/spring-webclient/

RestTemplate vs WebClient

• https://www.baeldung.com/spring-webclient-resttemplate
• https://stackoverflow.com/questions/47974757/webclient-vs-resttemplate