teleren/devto huggingface dataset:
Java – Convert Excel File to/from JSON (String/File) – using Apache Poi + Jackson
Tags: java, excel, apachepoi, jackson
Published: 2021-05-10 07:18:42

https://ozenero.com/java-convert-excel-file-to-from-json-string-file-using-apache-poi-jackson

Java – Convert Excel File to/from JSON (String/File) – using Apache Poi + Jackson

In the tutorial, Grokonez shows how to convert Excel File to JSON String or JSON File and vice versa with Java language by examples.

<!--more-->
<h2>Dependencies</h2>

<pre><code class="language-html">&lt;dependency&gt;
	&lt;groupId&gt;org.apache.poi&lt;/groupId&gt;
	&lt;artifactId&gt;poi-ooxml&lt;/artifactId&gt;
	&lt;version&gt;3.17&lt;/version&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
	&lt;groupId&gt;com.fasterxml.jackson.core&lt;/groupId&gt;
	&lt;artifactId&gt;jackson-databind&lt;/artifactId&gt;
	&lt;version&gt;2.8.5&lt;/version&gt;
&lt;/dependency&gt;</code></pre>
<h2>Excel to JSON</h2>
<h3>Excel File to JSON String</h3>
We do 2 steps:
– Step 1: Read Excel File into Java List Objects
– Step 2: Convert Java List Objects to JSON String

-> Excel File: <a href="https://ozenero.com/wp-content/uploads/2019/02/customers-1.xlsx">customers</a>

<img src="https://ozenero.com/wp-content/uploads/2019/02/convert-excel-file-to-from-json-file-string-excel-file.png" alt="convert-excel-file-to-from-json-file-string---excel-file" width="415" height="162" class="alignnone size-full wp-image-16892" />

<code>Customer.java</code>:

More at:

https://ozenero.com/java-convert-excel-file-to-from-json-string-file-using-apache-poi-jackson

Java – Convert Excel File to/from JSON (String/File) – using Apache Poi + Jackson
Codewell — Free Front End Coding Challenges!
Tags: showdev, webdev, html, css
Published: 2021-05-10 07:14:20

Hi everyone! Can't believe about to show off something my friend and I have been working on for the past 3 months, it still doesn't feel real!

I'm a Product Designer who's always been adamant about learning coding but never got around to actually doing it (I'm okay with HTML and CSS skills) but I have noticed that I always design and code the frontend just for fun and in the process, I learn a lot from Google and Youtube. 

**I'd like to introduce to you [Codewell](https://codewell.cc)** — improve your HTML and CSS skills by practicing on real design templates.

We’re starting off the release with 9 free templates — our goal is to build a growing community of developers eager to learn and share their solutions, and there’s no better way to do that but by making the templates accessible to everyone.

We'd love it if you take a look at Codewell and jot down your thoughts!

Looking forward to seeing you on Codewell!
Understanding Docker: part 32 – Networks
Tags: docker, devops, beginners, cloud
Published: 2021-05-10 07:12:48

---
title: Understanding Docker: part 32 – Networks
published: true
description: Serie of sketchnotes about Docker. Explaining in a visual way Docker principles.
tags: Docker, DevOps, beginners, Cloud
series: Understanding Docker in sketchnotes
cover_image: https://dev-to-uploads.s3.amazonaws.com/uploads/articles/th82459087ewajcdhdnb.jpg
---

Understanding Docker can be difficult or time-consuming. In order to spread knowledge about Cloud technologies I started to create sketchnotes about Docker. I think it could be a good way, more visual, to explain Docker (and other technologies like Kubernetes and Istio).

We continue the series of Docker sketchnotes with a focus about Docker networking.

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/th82459087ewajcdhdnb.jpg)
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/dtuekxbuewqa210c3brz.jpg)
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/uvko9ozsv55zw3z5efda.jpg)
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/yn2hciyc6avt3pwug914.jpg)
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/mv3t9zrub9g65k56tq8n.jpg)
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/6df0qb453rwtdxkrgg2i.jpg)

As usual, if you like theses sketchnotes, you can follow me, and tell me what do you think. I will publish others sketchs shortly :-).

If you are interested, I published all the sketchnotes on Docker (and new ones!) to make a "book" of 93 pages: ["Understanding Docker in a visual way"](https://gumroad.com/aurelievache#YTLzM).
How to implement password policy on your MySQL databases
Tags: mysql, security, database, cloudskills
Published: 2021-05-10 07:03:58

Check out how to use 'validate_password' to set up strong password policy to better protect your production database in 10 mins.

[Watch Now >](https://www.youtube.com/watch?v=u2pzfIsnjk0)
[Explore Cloud Managed RDS MySQL for FREE >](https://www.alibabacloud.com/product/databases#J_2463051000)


[Official Documentation >](https://dev.mysql.com/doc/refman/8.0/en/validate-password.html)

【Scripts】
Mysql 5.7
```
// weak password
create user test identified by 'admin';
Drop user test;

//check if validate_password is installed?
SELECT PLUGIN_NAME, PLUGIN_LIBRARY, PLUGIN_STATUS, LOAD_OPTION 
FROM INFORMATION_SCHEMA.PLUGINS 
WHERE PLUGIN_NAME = 'validate_password';

// install plugin
INSTALL PLUGIN validate_password SONAME 'validate_password.so';

// check status
select * from mysql.plugin;
SHOW GLOBAL VARIABLES LIKE 'validate_password%';

// test 
create user test identified by '123456';
create user test identified by 'Passw@rd1';
drop user test;

//change variables
SET GLOBAL validate_password_policy=LOW;

//uninstall
UNINSTALL PLUGIN  validate_password;
```

===========
MySQL 8.0

```
// weak password
create user test identified by 'administrator';
Drop user test;

// check if installed?
SELECT * FROM mysql.component;

// install the component
INSTALL COMPONENT 'file://component_validate_password';

// see system variables
show variables like 'validate_password%';
SHOW STATUS LIKE 'validate_password%';

// test
create user test identified by '123456';
create user test identified by 'Passw@rd1';
drop user test;

// change the variables
SET GLOBAL validate_password_policy=STRONG;

// uninstall
UNINSTALL COMPONENT 'file://component_validate_password';
```
React error
Tags: reactnative, react, javascript, npm
Published: 2021-05-10 06:29:05

I installed create-react-app and started a mini project today .
so, i started by creating an react app using command npx create-react-app App , after few minute it is created . now, when i run command npm start then i got the error , plz help me to resolving this issue.

error is like this as following:

./src/index.css (./node_modules/css-loader/dist/cjs.js??ref--5-oneOf-4-1!./node_modules/postcss-loader/src??postcss!./src/index.css)
TypeError: Cannot read property 'prefix_exceptions' of undefined
    at Array.map (<anonymous>)
It's out now - Berry Free React Admin Template
Tags: opensource, react, javascript, webdev
Published: 2021-05-10 06:28:03

It's finally here. Berry open-source react admin template is available to download. 

If you don't know about Berry - Here is my post on [Everything about Berry](https://dev.to/rakesh_nakrani/all-you-need-to-know-about-berry-react-li6). This product is minimal yet beautiful for your next React backend project.

> Berry is managed by team @CodedThemes

We have made lots of design Iteration and usability testing to overcome the customer’s pain points. Our customer-first approach gives us the motivation towards the Berry journey. You feel amazed after seeing the Berry User Interface.

It is build using Material-UI a top-rated Material design React component library. For newcomers React is an open-source library, the most popular at this moment which actively supported by Facebook.

##Table of contents
 * [Why Berry?](#why-berry)
 * [Download](#download)
 * [Getting Started](#getting-started)
 * [Documentation](#documentation)
 * [Technology Stack](#technology-stack)
 * [License](#license)

###Why Berry?
Berry brings everything you need for dashboard development. We have added the following features in the initial release.
 * Modern aesthetics UI design
 * Material-UI components
 * Fully Responsive, all modern browser supported
 * Easy to use code structure
 * Flexible & High-Performance code
 * Easy Documentation Guide

### Download
{% github https://github.com/codedthemes/berry-free-react-admin-template %}

**Free Version**
 * [Live Preview](https://berrydashboard.io/free/dashboard/default)
 * Download from [Github](https://github.com/codedthemes/berry-free-react-admin-template)

**Pro version**
 * [Live Preview](https://berrydashboard.io)
 * [Purchase](https://material-ui.com/store/items/berry-react-material-admin/)

###Getting Started
Clone from GitHub
`git clone https://github.com/codedthemes/berry-free-react-admin-template.git`

###Documentation
Berry documentation helps you out in all aspects from installation to deployment.

###Technology Stack
 * [Material-UI](http://material-ui.com) Component library.
 * Built with React Hooks API.
 * Redux & React Context API for State Management.
 * React Router for Navigation Routing.
 * Support of react-script.
 * Code Splitting.
 * CSS-in-JS where CSS is composed using JavaScript instead of defined in external files.

###Issues
Please generate a [GitHub issue](https://github.com/codedthemes/berry-free-react-admin-template/issues) if you found a bug in any version. We love to resolve any issue.

###License
**Free** version cover under [MIT](https://github.com/codedthemes/datta-able-bootstrap-dashboard/blob/master/LICENSE)


###Follow us
Website [https://berrydashboard.io](https://berrydashboard.io)
Blog [https://blog.berrydashboard.io](https://blog.berrydashboard.io)
CodedThemes [https://codedthemes.com](https://codedthemes.com)
Dribbble [https://dribbble.com/codedthemes](https://dribbble.com/codedthemes)
Facebook [https://www.fb.com/codedthemes](https://www.facebook.com/codedthemes)
Twitter [https://twitter.com/codedthemes](https://twitter.com/codedthemes)
Where to store SSH key (For Windows) 🔑
Tags: linx, windows, wsl, ssh
Published: 2021-05-10 06:19:26

### Prerequisites
* Windows Subsystem for Linux (WSL) is installed
* For this example we will use the Ubuntu Linux distro/distribution.
* [Visit this link to rocket academy to find out more about WSL](https://bootcamp.rocketacademy.co/course-logistics/required-hardware-and-software#windows)

***

# Step 1: Understand how to access Linux On Windows<br><br>

#### Method 1: Using the file explorer<br>
1. Type `\\wsl$\` into the file explorer. This will direct you to the location of the Ubuntu folder.
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/xj9pniw925dvoylfkq08.jpg)

2. Navigate to your linux folder. `Ubuntu -> Home -> <LINUX USERNAME>`
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/2xp4e3sdn2np9277r713.jpg)

#### Method 2: Using the WSL terminal
```
# This command navigates to the linux folder

cd ~/
```
```
# This command lists the files that are in the linux folder

ls -a ~
```
****

# Step 2:  Create .ssh folder (this is where we'll put the ssh key)
_Notes: If this is your first time accessing this folder, you probably do not have a folder for ssh files and will have to create your own._ <br><br>

#### Method 1: Using the file explorer
1. Create a folder in your linux folder and name it ".ssh"
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/k6y5nzxv2pn8vujddnyh.jpg)
2. Done! Now you can put the key pairs in this folder



#### Method 2: Using the WSL terminal 
```
# 1. Check if you have a .ssh folder. If you don't have an ssh folder it'll return "No such file or directory"

ls ~/.ssh
```

```
# 2. Create a folder called .ssh 

mkdir ~/.ssh
```
```
# 3. Copy any key pairs you need into this folder
# Note: You have to be in the same directory as the file you want to copy
# syntax: cp <FILENAME> ~/.ssh

cp my-aws-ec2-keypair.pem ~/.ssh
```
Spring Boot and Kubernetes
Tags: springboot, kubernetes, k8s
Published: 2021-05-10 06:06:46

---
title: Spring Boot and Kubernetes
published: true
description: 
tags: #springboot #kubernetes #k8s

//cover_image: https://direct_url_to_image.jpg

---
[Please checkout in my github repository](https://github.com/PheaSoy/spring-boot-kubernetes)
Angular CLI installation without internet
Published: 2021-05-10 05:53:08

Hi Team,
Can you advice how to install Angular CLI without internet(OS:Windows server2019). I have installed the "npm", but we can't use the command "npm install -g @angular/cli" as I don't have internet access. Please check the image attached.
FYI, I have another system with AngularCLI and having Internet access as well.

Thanks 
Linu
Setting up Python on Windows
Tags: python, programming, devjournal
Published: 2021-05-10 05:39:52

Recently I have been learning Python. I learned Java in college but it seems that Python is more used in tech industries. As my first post about Python, I will start by talking about how to set it up on Windows. I learned that there are 3 different ways to install it on your system. 

1. The Microsoft Store
2. The full installer
3. Windows Subsystem for Linux


In this article, I will introduce how to set it up using the Microsoft store. First, check if your system already has Python installed.

    Press the Win key.
    Type PowerShell.
    Press Enter. 

Then in your command line type 

    python --version
    //Python 3.8.4
 if you see a response that is the current version installed on your machine. 

#Installing Python from Windows store

Step 1: Open the Python App Page in the Microsoft Store
Open the Microsoft Store app and search for Python.

![image](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/gfbsdjyjj3x7d62q3768.png)
 
Select Python the highest version number you see available in the app, to open the installation page. Continue with all the setup instructions and you should have Python ready on the machine.

Another tip from reading countless articles is to install Pycharm. PyCharm is a cross-platform IDE that provides consistent experience on the Windows, macOS, and Linux operating systems. Here is the link to the website to set it all up.
https://www.jetbrains.com/help/pycharm/installation-guide.html

I hope you enjoyed it, please let me know if you have any questions or concerns about setting up Python and I will aid as much as I can.
Problems with running java programs using CLR
Tags: java, computerscience, codenewbie, career
Published: 2021-05-10 05:29:13

Starting with Java? 

Well, the first step as a newbie would be to install JDK - Java Development Kit. In earlier versions of JDK, there used to be a private JRE (Java Runtime Environment) as well as a public JRE as well. In later versions, the structure is changed, and we get only one folder of JDK, with private JRE. No Public JRE.
With the latest JDK version 16 in the market, one should still always go for the version which provides LTS - Long Time Support.
Currently, one should opt for Java SE 11 (LTS). 

Now, Before running a program from the command line in java, things to be taken care of:

A.  Set PATH variable in environment variables. It will tell the OS where the java executables like javac, java.exe are located. Set it to point `JDK version/bin` folder
    
B.  Then, check if the classpath is set already?
Classpath will tell the java interpreter where to find java *class file* to run.
If it is not, leave it as it is. If it is already set to some value, make sure you add, current directory in that as well. Denote current directory by  `.;` 

C.  To run a program from the command line, go to the *source root folder* and then run the execute java command along with a fully qualified package name. i.e., java com.rajnesh.MainClass

    Like below:

 ![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/40xbonphbw6k8m7yfxs2.PNG)


    Running it from anywhere else would throw this exception:

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/2vhqw3d3gldss6y6qy94.PNG)
Bug Tools
Published: 2021-05-10 05:15:29

So in my last blog I spoke about how we as developer's break down big problems into little one's. That being said the next question is what tools do we use to help us solve these problems. 

As developers debugging comes with the territory. 

Let's look at some of our tools.

## Binding.pry 
     Binding.pry allows us to run our code up to a certain point and then stop it. Allowing us to check different aspects of our code up to that point. This way we can insure that our code is working as we intended it to work. With binding.pry stoping our code example. We can now check to the params for this method, the return value of @user and others aspects of this code up to this point. 

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/iaree5rg1wbqmo4nl8qf.png) 

## Byebug 
     Byebug is very similar to binding.pry. But it offers more functionality to us. One of the biggest differences with using byebug is that we are able to move through our code while testing it. So we are able to test more of our code without leaving the pry session.     

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/vxgencssauvekgt7pozx.png)
      
## Rails Console
     Rails console gives us a couple of options that we don't have with binding.pry or byebug. Similar to our pervious two tools we can check aspects of our code to insure we are getting the results we want. But rails console also allows us to create data that we can persist to our database. If we wanted the option to test our code without persisting to the database we also have the option of opening up a sandbox in the console with the rails c -s command. Using the rails console sandbox. We are able to create data and test it but It will not persist to the database. 

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/eukx2i63y8remi5wxig7.png)

Hopefully this has been a helpful in giving you a look into some option in your debugging/coding journey.
Introducing: Mint UI 🎉
Tags: showdev, webdev, news, mintlang
Published: 2021-05-10 05:14:38

Finally after months (and months) of work, I'm proud to present: [Mint UI](https://ui.mint-lang.com)!

![TA-DA](https://media.giphy.com/media/JqDeI2yjpSRgdh35oe/giphy.gif)

So that was a bit anticlimactic 😅 you probably don't know what the hell I am talking about so let me show you!

[Mint UI](https://ui.mint-lang.com) is a component library written in [Mint](https://www.mint-lang.com) - a programming language specifically designed for [Single Page Applications](https://en.wikipedia.org/wiki/Single-page_application).

Keep on reading, to see some of it's features - in video!

## Components Galore

Mint UI has **60+ components** that you can use to build your next great application (or side project 🙂).

{% vimeo 544021674 %}

That was just a taste, you can play around with all the components on the [website](https://ui.mint-lang.com/components).

## Seamless Sizing

The size of components are completely fluid, controlled by the `font-size` property - `em` is used everywhere - so you can make them as large or as small as you want! As a bonus any children will be sized accordingly as well!

{% vimeo 544015375 %}

## Mobile Support

Most components adapt to the screen size by using media queries, but some change based on available space.  

For example the [table](https://ui.mint-lang.com/components/ui-table) changes into a [definition list](https://ui.mint-lang.com/components/ui-definition-list) if it's width goes below a defined number.

{% vimeo 544017739 %}

## Keyboard Support

All interactive elements besides can be interacted with with mouse and keyboard.

{% vimeo 544168530 %}

## Light and Dark modes

Mint UI supports light and dark modes and even has a [component to toggle them](https://ui.mint-lang.com/components/ui-dark-mode-toggle) built in!

{% vimeo 544016909 %}

## Themeable with CSS variables

All components can be themed with design tokens by using CSS variables.

{% vimeo 544213488 %}

Currently only colors can be changed but in future versions there will be all kinds of tokens (paddings, spacing, etc...). 

## Powered by Mint

Mint UI is written in Mint and that means that you can't use in JavaScript projects (yet) only in Mint projects, but that's a good thing! Mint as everything you need to create production ready applications. 

If you are looking to learn Mint, I have a series on it here https://dev.to/gdotdesign/series/836

---------

## License

Mint UI is hosted on [Github](https://github.com/mint-lang/mint-ui) and its source code is public but it's licensed differently than other open source projects: it is free (even for commercial use) for individuals and small companies but a paid license is required for bigger companies (4 or more employees).

With the release there is a special 25% discount for the first 50 companies who purchase using these links:
https://gum.co/mint-ui-license/u5bjba8
https://gum.co/mint-ui/dbspk6a

---------

Let me know what do you think in the comments below!
META - Smart Vehicle Materials
Published: 2021-05-10 04:59:17

Discover META’s smart vehicle material in vehicle technology with keeping driver safe technology and more.

Quick Highlights - Vehicle Technology growing faster and come up with innovative features that has never thought before like sustainable solution, automated technology, increasing in fuel efficacy, car security and many more.

Metamaterial Inc. (META) - is manufacturing smart materials that manipulate interaction with light & other forms of energy and revolutionize solar solutions, aircraft security and wearable technology. All products are designed and manufactured by keeping sustainability as a high priority.

# Quick Links -
* What is Holography?
* What is heads-up display?
* What is De-icing / De-fogging?
* What is 5G Transparent Antennas?

# What is Holography?
Holography is a technique which records image in wavefront form and later on re-constructing a 3D light field that holds the depth and properties of the recorded image. Its is widely used in entertainment and in creating 3D security tags.

# What is heads-up display?
To follow safe driving needs to keep eyes on the road. Yet current layout of car required drivers eye attentions from road to collect information like speed, fuel state, navigation and many more. This create conflict between road and vehicle, which create risk for driver. Vehicle Technology addressed this problem and introduce head-up display (HUD) which allow to show all information on driver’s eye point.

This innovative technology helps driver to communicate with vehicle information while driving and keeping eyes on the road. Using HUD driver eyes do not have to adjust to different brightness and focal plane conditions.

META fabricated holographic optical that is key component in the optical system that makes up a Heads-Up Display. The combiner imposes light from the projector to the outside world while minimize impact of light from the road. META achieve these with large area holographic gratings.

# What is De-icing / De-fogging?
NANOWEB is word’s hight-performance transparent conductor made of an invisible metal mesh that can be fabricated onto any glass or plastic surface. NANOWEB has been developed using Rolling Mask Lithography (RML) which enables NANOWEB to produced for large-area products and devices. Nanoweb act as a resistive heater to generate heat on window and quickly defogging an surface.

Many vehicles now on a days either have blow air or have heat element lines that are visible on a glass surface for defrosting a window, especially on the rear window.

# What is 5G Transparent Antennas?
META’s transparent antennas manufacturer using NanoWeb material are integrated over the surface while maintaining visibility, such as vehicle windshields and windows. It has high conductivity maintained without sacrificing the electromagnetic behaviour of the antennas.

Want's to learn more about? Connect [KPITENG](www.kpiteng.com)

# Connect Us - 
KPITENG - Digital Transformation
W - [www.kpiteng.com](www.kpiteng.com)
E - hello@kpiteng.com
S - kpiteng