Kotlin SpringBoot 2 Spring Data JPA RESTful Web Service

Hi everyone.

I share example how to integration Kotlin - Spring Boot2 - Spring Data JPA-RESTful Web Service and CRUD example.


Technologies used:

1. Spring Boot 2.2.2.RELEASE
2. Gradle 2.x
3. Java 8
4. Eclipse: Oxygen.1.a Release (4.7.1a) or  IntelliJ Community
5. Spring Tools Suite (STS) 4
6. Postman
7. MySql

Code on GitHub:

https://github.com/HenryXiloj/Kotlin-SpringBoot2-RESTful


Steps:

Step 1:

Execute next script on MySql

CREATE TABLE users 
             ( 
                          id       INT(11) NOT NULL auto_increment, 
                          username VARCHAR(255) NOT NULL, 
                          password VARCHAR(255) NOT NULL, 
                          created TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP() on 
             UPDATE CURRENT_TIMESTAMP(), 
                    PRIMARY KEY (id) 
             )

Step 2: Import project on Eclipse or IntelliJ


Eclipse:

IntelliJ:  File -> open --> choose folder backend

Righ click on project  Gradle -> Refresh Gracle project (Eclipse)

IntelliJ:

View -> Tool Windows -> Gradle -> Righ click on project -> Refresh Gradle dependencies

Step 3.

Run project from directory on console next command:

./gradlew bootRun

Run project from IntelliJ :

View -> Tool Windows -> Gradle -> Execute Gradle Task -> gradle bootRun

Step 4: Test.

GET  (by default)

GET all users

http://localhost:8080/ws/users

GET user by id.

http://localhost:8080/ws/users/1

POST user (save)

http://localhost:8080/ws/users

PUT user (update user)

http://localhost:8080/ws/users/1

DELETE user.

http://localhost:8080/ws/users/1

Great :).

References:

https://kotlinlang.org/docs/tutorials/spring-boot-restful.html
https://www.callicoder.com/kotlin-spring-boot-mysql-jpa-hibernate-rest-api-tutorial/

Stop and Start JAR file in background CMD on Windows using bat file

I share example how to execute JAR file in background or if you want execute command line in background on Windows.

Steps:

1. Create file start.bat and add next code.

@echo OFF
cd C:\path_your_jar
start javaw -jar your_jar.jar


2. Create file stop.bat and add next code. for example if you application up in the port 9000 then you find the port and PID and kill.

@ECHO OFF                                                                           
FOR /F "tokens=5" %%T IN ('netstat -a -n -o ^| findstr "9000" ') DO (
SET /A ProcessId=%%T) &GOTO SkipLine                                                 
:SkipLine                                                                           
echo ProcessId to kill = %ProcessId%
taskkill /f /pid %ProcessId%

or

if you want to find jar and to change the next line.

@ECHO OFF                                                                           
FOR /F "tokens=1" %%T IN ('jps -m ^| find "jar" ') DO (
SET /A ProcessId=%%T) &GOTO SkipLine                                                 
:SkipLine                                                                           
echo ProcessId to kill = %ProcessId%
taskkill /f /pid %ProcessId%

That is it.

Docker command line

Docker compose up

docker-compose -f my_docker-compose.yml up

Removing All Unused Objects

docker system prune

Stop a particular container

docker container stop <<container_id>>

Removing Docker Containers

docker container ls -a

docker container rm id_container id_container

Remove all stopped containers

docker container ls -a --filter status=exited --filter status=created

docker container prune

Removing Docker Images

docker image ls

docker image rm id_image id_image

Remove dangling and unused images

docker image prune

Create your first docker container from repository (Docker hub)

docker search ubuntu (images name)

docker pull name_image

docker images

docker run -i -t image_id /bin/bash

exit

docker ps -a

docker start container_id

docker attach container_id (optional)

docker commit container_id your_name_image (optional)

Build an image with the Dockerfile

(I use “.” because you need to have Dockerfile in current directory).

docker build -t name_image .

Launching a container

docker run -ti my_image /bin/bash

Rename docker image

docker tag <old_name> <new_name>

docker rmi <old_name>

Push image on dockerhub or docker registry

docker tag id_image id_docker/your_name_image:your_version

docker push id_docker/your_name_image:your_version

Add your username to the docker group

sudo usermod -aG docker YOUR_USER

To apply the new group membership

su - YOUR_USER

Check if you user is added.

id -nG

Login to docker registry

docker login your_ip:your_port

usermame: your_username_docker_registry

password: your_pass_docker_registry

Running image detach mode

docker run -d --rm -p 9000:8080 your_image:version

Copy file in container.

docker cp path_local_file your_container_name:/path_file_your_replace

MariaDB

docker network create some-network 

docker run --detach --network some-network --name some-mariadb --env MARIADB_USER=<<YOUR_USER>> --env MARIADB_PASSWORD=<<YOUR_PASSWORD>> --env MARIADB_ROOT_PASSWORD=<<YOUR_PASSWORD>>  mariadb:latest

docker run -it --network some-network --rm mariadb mysql -hsome-mariadb -u <<YOUR_USER>> -p

Running Oracle database XE 11G using Docker

I share example how to install Oracle 11g on Docker.

Steps:

1. I get image from https://hub.docker.com/r/pengbai/docker-oracle-xe-11g-r2/

2. this commands is optional, if you want to use docker without sudo then add your current user on docker.

Add your username to the docker group

sudo usermod -aG docker YOUR_USER

To apply the new group membership

su - YOUR_USER

Check if you user is added.

id -nG

3.  Pull image

docker pull pengbai/docker-oracle-xe-11g-r2

Run with 8080 and 1521 ports opened:

docker run -d --shm-size=1g -p 1521:1521 -p 8080:8080 pengbai/docker-oracle-xe-11g-r2

Note: It's important to run Oracle XE with >1GB shared memory.

check container

docker ps

Wait one moment for start up oracle

Check  docker logs 

docker logs -f YOUR_ID_CONTAINER

4. Connect database with following setting:

Go to. http://localhost:8080/apex

Connect to Oracle Application Express web management console with following settings:

url: http://localhost:8080/apex
workspace: internal
user: admin
password: oracle








































Change password and press return button


































Login again. if login is correct display this.














































Try to connect Sql Developer or by console use this.

hostname: localhost
port: 1521
sid: xe
username: system
password: oracle

I recommend change the password of user system, with next commands.

alter user system identified by newpa$$word;

alter user system account unlock ;

And check status users:

select username, account_status, EXPIRY_DATE from dba_users




References:

https://hub.docker.com/r/pengbai/docker-oracle-xe-11g-r2/

https://github.com/PengBAI/docker-oracle-xe-11g

http://www.dba-oracle.com/t_make_password_not_expire.htm



















Install SQLPlus client on Ubuntu 20.04 or CentOS 8

I share example how  to install SQLPlus client on Ubuntu or Centos

UBUNTU

Steps:

1.   you need to install alien package.

sudo apt-get install alien

2. You need to download Instant Client Downloads ,  you choose the current version on page (basic*.rpm,  sqlplus.rpm and devel*.rmp).  you run command with your version.

sudo alien -i oracle-instantclient*-basic*.rpm
sudo alien -i oracle-instantclient*-sqlplus*.rpm
sudo alien -i oracle-instantclient*-devel*.rpm

3. Create Oracle configuration file:

sudo sensible-editor /etc/ld.so.conf.d/oracle.conf

4. Add the next line,  depends if your machine 32 or 64 bit.

#for 32 bits
/usr/lib/oracle/<your version>/client/lib/ 

#for 64 bits
/usr/lib/oracle/<your version>/client64/lib/

 

5. Update the configuration

sudo ldconfig

6. Try to connect using:

# if you have 32 bits
sqlplus username/password@//dbhost:1521/SID

# if you have 64 bits
sqlplus64 username/password@//dbhost:1521/SID

CENTOS 8

Steps:

1. You need to download Instant Client Downloads ,  you choose the current version on page (basic*.rpm,  sqlplus.rpm and devel*.rmp).  you run command with your version.

sudo yum localinstall oracle-instantclient*-basic*.rpm
sudo yum localinstall oracle-instantclient*-sqlplus*.rpm
sudo yum localinstall oracle-instantclient*-devel*.rpm

2.  Run the next command

sudo yum install libnsl 

3. Create Oracle configuration file:

sudo nano /etc/ld.so.conf.d/oracle.conf

4. Add the next line,  depends if your machine 32 or 64 bit.

#for 32 bits
/usr/lib/oracle/32/client/lib/ 

#for 64 bits
/usr/lib/oracle/64/client64/lib/ 

5. Update the configuration

sudo ldconfig

6. Try to connect using:

# if you have 32 bits
sqlplus username/password@//dbhost:1521/SID

# if you have 64 bits
sqlplus64 username/password@//dbhost:1521/SID

That is it.




References: https://askubuntu.com/questions/159939/how-to-install-sqlplus/207145

How to Install Docker on Linux Ubuntu 18.04

I share example how to install docker on ubuntu using default repositories:

Steps:

1. Update Software repositories on terminal

sudo apt-get update

2. If you have old version uninstall.

sudo apt-get remove docker docker-engine docker.io

3. Install Docker.

sudo apt install docker.io

4. Start and Automate Docker.

sudo systemctl start docker

 sudo systemctl enable docker

5. Check version.

docker --version

That is it.







References: https://phoenixnap.com/kb/how-to-install-docker-on-ubuntu-18-04

Spring Boot profile with maven

I share example how to add profile in spring boot with maven.

For example :

1. I add 3 profiles on pom.xml by default profile prod is active.

-local
-dev
-prod




2. Also add on pom.xml on section <build></build>



3. Add 3 file on Spring boot project src/main/resources, each file is one profile.





4. Add into application.properties



5. if you want change profile create file application.yml and write:



In the image the local is the profile active if you change, change the position the profile. the concepts is similar a pile. if you don't want to create file application.yml then into the application.properties (spring.profiles.active=prod).

that is it.

LocalStorage, SessionStorage or Native Session (Angular 7 or greater)

I share example how to integrate LocalStorage, SessionStorage or Native session storage, Native local storage.

LocalStorage: If you create  local storage value, the value exist on the browser.
SessionStorage: If you create session storage value, the value exist just current tab browser, if you open new tab the value doesn't exist.

Native session is similar concepts, but you don´t need to install anything. check in the end the blog. I recommed use native session or native local storage.

Use ngx-webstorage

1. Install on project angular.

npm install --save ngx-webstorage

2. Add app.module.ts

imports: [

NgxWebstorageModule.forRoot(),

]

3.  Import on your component

import {LocalStorageService, SessionStorageService} from 'ngx-webstorage';

4. Add on your constructor

constructor(private localSt:LocalStorageService,

private sessionSt:SessionStorageService) {}

5. Examples

/*Set*/

this.localSt.store("keyLocal", "value");

this.sessionSt.store("keySession", "2");

/*Get*/

this.localSt.retrieve("keyLocal");

this.sessionSt.retrieve("keySession");

/*remove*/

this.localSt.clear("keyLocal");

this.sessionSt.clear("keySession");

Native session or local storage javascript

*add*

sessionStorage.setItem("YOUR_KEY", YOUR_VALUE)




*Get*

sessionStorage.getItem("YOUR_KEY")




*Remove*

sessionStorage.removeItem("YOUR_KEY")







*add*

localStorage.setItem("YOUR_KEY", YOUR_VALUE)




*Get*

localStorage.getItem("YOUR_KEY")




*Remove*

localStorage.removeItem("YOUR_KEY")




XML Java Transformer outputs instead of <>

I share example how java Transformer outputs &lt; and &gt; instead of <> on XML.

/**
Example
*/

import java.io.StringReader;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.commons.lang.StringEscapeUtils;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;

public class Test {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub

        String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>" +
            "&lt;company&gt;" +
            "&lt;staff id=\"1001\"&gt;" +
            "&lt;firstname&gt;henry&lt;/firstname&gt;" +
            "&lt;/staff&gt;" +
            "&lt;/company&gt;";



        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(new InputSource(new StringReader(StringEscapeUtils.unescapeXml(xml.toString()))));

        System.out.println("final xml " + xmlTransformerInput(doc).toString());

    }


    public static String xmlTransformerInput(Document fDoc) {

        try {

            fDoc.setXmlStandalone(true);
            DOMSource docSource = new DOMSource(fDoc);
            Transformer transformer = TransformerFactory.newInstance().newTransformer();
            transformer.setOutputProperty(OutputKeys.METHOD, "xml");
            transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            StringWriter sw = new StringWriter();
            transformer.transform(docSource, new StreamResult(sw));

            return sw.toString();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }

    }

}

Create new Database from command line Oracle 11g Express

I share example how to create new user from command line, you need SQL*Plus or JDeveloper and super user, I'm using Oracle 11g Express for that use the user SYSTEM.

Steps:

Step 1:

connect SYSTEM/password; 

Step 2:

CREATE USER your_schema IDENTIFIED BY your_password; 

Step 3:

ALTER USER your_schema QUOTA UNLIMITED ON SYSTEM; 

Step 4:

GRANT CREATE SESSION, CONNECT, RESOURCE, DBA TO your_schema; 

Step 5:

GRANT ALL PRIVILEGES TO your_schema; 

You try connect with the new user.

That's it.