Spring Boot

TOPIC CRUD API

CRUD Operation	HTTP Method	Response Code
Create	POST	201
Read	GET	200
Update	PATCH / PUT	200
Delete	DELETE	200

Setup Java and Maven in MAC

Need Maven to install 
Download version 19 (for example ) from https://jdk.java.net/19/
and Install as below:

For Mac

Downloading Java for Mac OS:
$ tar -xvf openjdk-19.0.1_macos-x64_bin.tar.gz
$ sudo mv jdk-19.0.1.jdk /Library/Java/JavaVirtualMachines/

Setting Environment Variables - JAVA_HOME and Path
$ JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk-13.0.1.jdk/Contents/Home"
$ PATH="${JAVA_HOME}/bin:${PATH}"
$ export PATH

Verifying the JDK installation
$ java -version


Maven for Mac OS  https://maven.apache.org/download.cgi
$ tar -xvf apache-maven-3.8.6-bin.tar.gz

Setting Maven Environment Variables - M2_HOME and Path
$ export M2_HOME="/Users/pankaj/Downloads/apache-maven-3.6.3"
$ PATH="${M2_HOME}/bin:${PATH}"
$ export PATH

Verifying the Maven Installation
$ mvn -version     

Deployment

Clean MVN ( clean the target | download necessary dependencies | compile run the unit tests )
and Create a JAR file and make that aviable in the project directory 

$ mvn clean install   

        = JAR FILE =  
        /target/demo-0.0.1-SNAPSHOT.jar

Run JAR FILE :
$ java -jar target/demo-0.0.1-SNAPSHOT.jar


PUSH TO HEROKU
https://docs.spring.io/spring-boot/docs/current/reference/html/deployment.html#deployment.cloud.heroku

Heroku CLI

Install Heroku for MAC
$ brew tap heroku/brew && brew install heroku
$ heroku login

instructions:
https://devcenter.heroku.com/articles/getting-started-with-java#prepare-the-app

Docker

Building and Running the Container
$ docker build -t javaspring .

Run the container
$ docker run -it -p 8080:8080 javaspring

Utils:
$ docker ps -a
$ docker stop container_id

GENERATE RSA

Note: keep the .pem inside : resources/certs directory

# create rsa key pair
$ openssl genrsa -out keypair.pem 2048

# extract public key
$ openssl rsa -in keypair.pem -pubout -out public.pem

# create private key in PKCS#8 format
$ openssl pkcs8 -topk8 -inform PEM -outform PEM -nocrypt -in keypair.pem -out private.pem

TASK SCHEDULER

Dependency: awaitility
We will use awaitility for scheduled.

Step 1: Add annotation @EnableScheduling in main class
Step 2: Use @Scheduled(fixedRate = 9000L) for 9 secs other are available like cron | fixedDelay

ASYNC for concurrent

No Dependency is needed. 

Step 1: Add annotation @EnableAsync in main class 
Step 2: Make a config file like: AsyncConfiguration.java
Step 3: Make a service and use annotaiton @Async for the method - with CompletableFuture
Step 4: Use commandline tools or controller  - with CompletableFuture

IMAGE UPLOAD and store into db tables by bytes

API: POST / upload
1. http://localhost:8080/api/v1/images/upload

Get Image by Name:
2. http://localhost:8080/api/v1/images/<name>/info

Get Image info by Name
3. http://localhost:8080/api/v1/images/<name>/info