Posts by Year

2020

less than 1 minute read

[Java] First learning java #3 expressions and operators

less than 1 minute read

What is an expression? public class Main { public static void main(String[] args) { int a; int b; a = 20; b =a+5; System.out.println(a); System.out.println(...

[Java] Double-click to open jar file on Windows

less than 1 minute read

Open jar file on windows When I made a jar file for distribution and distributed it, I could easily open it by double-clicking on Mac, but it could not be o...

[Java] Decorator pattern

2 minute read

What is Derocator pattern Decorate the objects.

[Java] Composite pattern

2 minute read

What is the ### Composite pattern? The container and the contents are identified and a recursive structure is created.

[Java] [ev3 × Java] Display, sound, LED control

2 minute read

This article is for people who want to operate ev3 with Java. This time, I would like to use intelligent blocks to display text, make sounds, and control LE...

[Java] Strategy pattern

3 minute read

What is the ###Strategy pattern? Any program is written to solve a problem. And a specific algorithm is implemented to solve the problem. In the Strategy pa...

[Java] Rock Paper Scissors in Java

1 minute read

Fixed [Q&A] Java “variable strA may not be initialized” error cause-Qiita

[Java] Bridge pattern

2 minute read

What is Bridge pattern It bridges between “function class hierarchy” and “implementation class hierarchy”. Wikipedia says it aims to extend the class in mul...

[Java] IntelliJ IDEA success tips

6 minute read

This blog post introduces the Java integrated development environment of IntelliJ IDEA and discusses the secrets of its success.

[Java] Java threading

2 minute read

[Java thread processing]

[Java] Java string

1 minute read

[Java string]

[Java] Java add form field to PDF

2 minute read

PDF form fields, also known as interactive fields, are primarily used to collect user information. Common form fields include radio buttons, check boxes, li...

[Java] Builder pattern

3 minute read

What is the ###Builder pattern? This refers to a pattern in which each part that makes up the whole is created and assembled in stages.

[Java] AbstractFactory pattern

4 minute read

What is AbstractFactory pattern? Create abstract products by combining abstract parts. Pay attention to the interface (API), not to the specific mounting of...

[Java] [Java] Random method

less than 1 minute read

Java.util.Random java.lang.Math, a class that comes with Java from the beginning There are these two.

[Java] VisualVM (JMX connection) with Kubernetes

4 minute read

Introduction This time I’m going to connect to a Java app running on k8s with VisualVM. I think it will be used when monitoring and analyzing Java applicati...

[Java] How to create H2 Database database anywhere

less than 1 minute read

Introduction When creating a new H2DB database, the system default JDBC URL: jdbc:h2:~/test (not C:\Documents and Settings[username]\test) This is a solutio...

[Java] [Java basics] What is Class

6 minute read

Introduction This article is friendly Java I wrote it for the purpose of organizing the knowledge I learned by myself with the reference book.

[Java] @PostConstruct

1 minute read

What is @PostConstruct Initialization method Initialization part of the object After creating the object, declare it in the method to be executed to ...

[Java] Use Hystrix and Sentinel in code examples

4 minute read

In this series of articles, I will introduce the open source Sentinel Java flow control project of Alibaba, comparing it with Hystrix.

[Java] Java Stream API

2 minute read

Introduction Java Are you using it! I often write something recently, but I think it has become quite convenient since the implementation of the Stream API....

[Java] ObjectMapper class

1 minute read

What is # Object Mapper ObjectMapper is the main actor class in the Jackson library. The ObjectMapper class provides functionality for reading and writing J...

[Java] About languages to learn

1 minute read

HTML ・Markup language developed to create web pages Other markup languages SGML XML ・Basically, it is structured from elements such as “title”, “headli...

[Java] #3 [Memorandum] do-while statement

2 minute read

Introduction Today’s Tokyo was cloudy, so it was cooler than usual during the day (I think there was 32℃, but…) Today I’m going to write about a do-while st...

[Ruby] Ruby problem⑦

1 minute read

This is the final episode.

[Ruby] rails AWS deployment is not reflected

less than 1 minute read

What to do if AWS deployment is not reflected environment rails 5.2.4 unicorn nginx For those who may not be immediately reflected in AWS when automatically...

[Java] First post

less than 1 minute read

Hi :shamrock:

[Ruby] Aizu Onene Judge

less than 1 minute read

This article is made as a memorandum so that you will not forget what you learned while working on Aizu Online Judge.

[Java] [Java] Conditional branch

less than 1 minute read

if statement The if statement determines the evaluation (comparison) results such as numbers and character strings. If the evaluation result is “true”, the ...

[Ruby] 6 ways to define options in thor

4 minute read

When creating a cli with Ruby, the standard gem thorusesmethod_optionwhendefiningcommandoptions(suchas--keyvalue). Use. However, if you refer to some blogs ...

[Ruby] Write a Ruby method using C (Numo::NArray)

5 minute read

(Added 08/20/2020) When passing an instance of Numo::DFloat as an argument, Numo::DFloat(view)#shape= When it is a view like, it may not be passed correctly...

[Ruby] save! method

1 minute read

While creating the flea market app, I did not understand the reason why the data was not saved even though the key was acquired. When I asked the mentor, he...

[Java] Overview of JavaScript and basic grammar

6 minute read

Premise This is a summary of what I have learned just after programming (1 to 2 months). There may be mistakes and mistakes in the actual site. If you notic...

[Java] Make yourself refactored two days ago.

9 minute read

Currently I am picked up by a certain company and undergo training as an engineer. The coin game created during the training was very bad, and I left it as ...

[Ruby] Launch Rails for EC2

13 minute read

Introduction The procedure for “using the AWS server” is divided into 5 parts.

[Java] JavaScript functions

3 minute read

Premise This is a summary of what I have learned just after programming (1 to 2 months). There may be mistakes and mistakes in the actual site. If you notic...

[Ruby] if else practice

2 minute read

Premise This is a summary of what I learned as a beginner in programming (1-2 months). It can be useless or wrong in the real world. If you notice it, I wou...

[Ruby] Automate deployment

6 minute read

Introduction The procedure for “using the AWS server” is divided into 5 parts.

[Java] What is a lambda expression (Java)

1 minute read

I could not understand the lambda expression for some reason, so I have simplified it and wrote the result.

[Ruby] Geeksalon

less than 1 minute read

From August, I will join a student-only programming salon called Geeksalon. Although I had been self-taught for a long time, I realized that it was tough an...

[Ruby] Edit Mysql using command in Docker environment

less than 1 minute read

Since Docker hasn’t been up for days yet for the first time, I’ll describe how to connect to Mysql in a terminal and play with it as a reminder.

[Ruby] EC2 initial settings

7 minute read

Introduction The procedure for “using the AWS server” is divided into 5 parts.

[Ruby] Draw a graph with Sinatra and Chartkick

1 minute read

Introduction I created a graph by improving the * [family todo list] created last time (https://qiita.com/superrino130/items/20f588f6a8b4d607c081#)* Complet...

[Java] [Java] Main data types

1 minute read

Overview List the major data types prepared in Java and organize the characteristics of each type.

[Java] [ev3×Java] Single motor control

7 minute read

This article is for people who want to operate ev3 with Java. This time I would like to control the motor in various ways.

[Ruby] Various GraphQL tests

2 minute read

Introduction Recently, I implemented the API with Graphql-ruby. Of course, I need to write a test for graphql, but since there seems to be various ways, I w...

[Ruby] Understand helper method form_with

less than 1 minute read

What is ##form_with form_with is one of the Rails helper methods and is described in the view file. This method allows you to send information.

[Ruby] line bot

less than 1 minute read

Quotations bot I made a bot that randomly replies the words of my favorite great person.

[Java] Java creates Word document

2 minute read

With its powerful word processing capabilities, Word is one of the most widely used tools in everyday work and life. In this article, I’ll show you how to u...

[Java] How to deploy kotlin(java) app with AWS fargate

1 minute read

Point If the amount of memory specified in the “task memory” of the fargate task definition is exceeded, the task will be killed. Therefore, it is nece...

[Ruby] [How to insert video in haml with Rails]

1 minute read

With the insertion of a video, you can decorate your website with style. This time I will explain in detail how to insert a video in haml with Rails.

[Ruby] I tried a calendar problem with Ruby

4 minute read

I am a beginner who is studying Rails. It’s been about a month since I first learned rails. While trying to learn Ruby from scratch, I came to the following...

[Java] [Java] I tried to solve Paiza’s B rank problem

7 minute read

Introduction I tried solving "the maximum average section of daily visitor numbers (equivalent to paiza rank B)" from the skill check past problem collectio...

[Ruby] 【rails g.error】

less than 1 minute read

◆ Spelling mistake when creating a file ・Rails g model massege Create a file with model above.

[Ruby] Training with each_with_index method

3 minute read

Use the each_with_index method to find the element you want to find in the array, Let’s create a method to find out what number the element is.

[Ruby] Rails fuzzy search function implementation

less than 1 minute read

WHY I was studying how to implement a search function using the LIKE clause and the Where method. .. .. However, the explanation of the level that can be ac...

[Ruby] Rails DB PostgreSQL changed to MySQL

1 minute read

Introduction Up to now, I used PostgreSQL to deploy to the database in the database, but if it is heroku, the mysterious phenomenon that the posted image di...

[Ruby] I can’t upload to heroku

less than 1 minute read

environment ・Rails 6.0.3.2 ・Mysql Ver 14.14 Distrib 5.6.47 ・OSX10.15

[Java] How to create a Java environment in just 3 seconds

less than 1 minute read

Introduction I will explain how to use Docker software to instantly create a java environment. Bug caused by managing some Java versions on local machine. T...

[Ruby] Technology for reading source code (cheat sheet)

24 minute read

1 overview According to what I hear, 80% of the work seems to be time to read the source code. However, despite the 80% sense of scale, there is no impressi...

[Ruby] Table design (using Active Hash)

3 minute read

Overview This time, I designed the table for making a clone site of the flea app. Since it is my first time to make it by myself, the quality of the table d...

[Ruby] Make Team Chat with Rails Action Cable

4 minute read

Introduction Since I made a team chat function with Action Cable in the portfolio, I will output it. Reference article I referred to the following article. ...

[Java] About java var

less than 1 minute read

java variable declaration var An organized memo for studying Java Silver…

[Ruby] [Rails] I want to load CSS with webpacker

less than 1 minute read

If you use rails ver.6 or later, I want to load CSS with webpacker instead of asset pipeline, so it is a memo because I implemented it.

[Ruby] [Rails Tutorial Chapter 4] Rails-flavored Ruby

1 minute read

Default value for the # argument The arguments specified when the method is called will be substituted in order from the beginning on the method side. At th...

[Ruby] rescueとrescue_from

2 minute read

Introduction There is no error in programming, but since the developers are human beings, it is possible to make mistakes, and network errors can cause the ...

[Ruby] Pokemon Go made with FakerGem

1 minute read

Background Use various gems in the process of programming learning. Looking at the source data on GitHub to get a better understanding of the Gem, I found s...

[Ruby] List of methods used in D rank of PAIZA

5 minute read

Introduction It is prohibited to post the answer as a major premise, so please use it for reference only. Since we can clear it without using the array or h...

[Ruby] I tried to organize the session in Rails

4 minute read

I am doing a lot of rails tutorials. I wrote an article about “session” which is dealt with in Chapter 8 this time because I want to organize it for my own ...

[Java] What’s in the Java SE Bronze exam

1 minute read

Java SE Bronze Exam Content Introductory qualification for inexperienced people. It aims to evaluate having a basic knowledge of object oriented programming...

[Java] Prototype pattern

3 minute read

Protytype pattern Instead of creating an instance from a class, it creates another instance from one. Create a new instance based on the model instance that...

[Ruby] Points to note when writing programs: Part 3

1 minute read

Points to note when writing programs: Part 3 1. Conclusion 2. What is Liskoff’s replacement principle? 3. Why is the Liskov replacement principle necessar...

[Java] Java add textbox to PowerPoint slide

1 minute read

A text box refers to a movable or resizable text or graphic container. In PowerPoint, whenever you need to add new content, you often need to insert a new t...

[Java] FizzBuzz problem

less than 1 minute read

I tried solving the FizzBuzz problem! I feel like it will be more refreshing, but I will try to solve it again.

[Ruby] [ruby] Drill output

less than 1 minute read

Content Implementation Comment First, in the third line, retrieve the value [“apple”, [200, 250, 220]] from fruits_price and assign it to the variable fru...

[Ruby] [Rails] Search books with Amazon PA API

3 minute read

It’s a little troubled with Amazon’s book search API, so take a note. I couldn’t find any other Japanese article, so I hope you find it useful. Introduction...

[Java] [Memorandum] Java: String search

4 minute read

Introduction I think I often use trim and contains. String search 1, contains Search whether a specific character string is included in the character string...

[Java] Singleton pattern

1 minute read

Singleton pattern A pattern that guarantees that only one instance exists.

[Java] I tried using Galasa

32 minute read

Introduction Galasa,atestingframeworkforhybridcloudapplicationsbasedonz/OS,isprovidedasanopensourceproject.Thisisonlyashorttimeafteritwasprovided(V0.3.0rele...

[Ruby] I got an error! *No interactive request template

1 minute read

While trying to learn the application implementation using Ruby on Rails, when I try to display the target page, the following screen is displayed: :sweat...

[Java] Hit Salesforce REST API from Java

2 minute read

Introduction This article is a memorandum of source code that hits REST API of Salesforce from Java. Since many parts such as property files are omitted, wr...

[Ruby] [Ruby]each nesting

less than 1 minute read

Overview I will summarize how to use each method in nesting for learning. *We do not touch on what each method is.

[Ruby] [Ruby] Project Euler Question 8

5 minute read

Problem Of the next 1000 digits, the maximum value among the powers of 4 adjacent digits is 9 × 9 × 8 × 9 = 5832.

[Ruby] [Rails] About migration files

1 minute read

What is a migration file A migration file is a file that describes the changes made to the database.

[Ruby] Supports zero drop of CSV output

less than 1 minute read

Introduction It is about the problem that 0 is omitted and 1 is output when you try to output the value such as 001 which has 0 at the beginning as CSV outp...

[Java] Java null coalescing operator

less than 1 minute read

While thinking that it’s not good because there is no null coalescing operator in Java As soon as the Util function is prepared

[Java] Factory Method pattern

3 minute read

Factory Method pattern In Template Method pattern, the super-class side creates the framework for processing, and the sub-class side flesh out specific proc...

[Ruby] About Rails controller

4 minute read

Overview I would like to explain the controller of a Rails application.

[Ruby] [Ruby] When you want to replace multiple characters

less than 1 minute read

gsub method If you want to replace multiple characters, you can use gsub and replace as specified. I corrected the article with a comment from @scivola. @sc...

[Java] [Memorandum] Java: Character string survey

2 minute read

Introduction This time, we will review and study Java that has been running away until now. As a result of touching Java for the first time, I became less c...

[Ruby] What is RubyGem?

1 minute read

I learned about Ruby libraries: writing_hand:

[Ruby] Ruby basics

1 minute read

Nice to meet you. Takumi. We started to improve our ability as an engineer. Thank you.

[Ruby] Release gem

2 minute read

Release gem of Ruby. To be precise, it was released in 2009 last time, so it will be the first re-release in 11 years. Refer to the following for the gem re...

[Java] Realized two-step authentication JAVA (TOTP)

5 minute read

1.First of all I want to realize two-step authentication of login by strengthening security measures by exposing a certain in-house system to the outside. A...

[Ruby] Rails render redirect_to

1 minute read

Introduction This time about the difference between render and redirect_to which are often used in Rails.

[Java] Let’s move to make Java more comfortable

2 minute read

This is an article to tell you that it was very nice to move from Java to Kotlin. Java drawbacks I was programming in Java a while back. But Java has its dr...

[Ruby] How can I efficiently fill the array?

less than 1 minute read

I will post it somehow. I was writing a program in ruby, but I realized that I still have a poor understanding of sequences. For example this

[Java] Check the H2 database on the Web

less than 1 minute read

Check H2 database on Web I often use the H2 database when doing private projects, I will write a method to check the H2 database on the Web.

[Ruby] About Ruby and object model

2 minute read

I learned about the basic language specifications of Ruby such as objects, classes and methods again in the Metapro book, so I wrote it down as a memorandum

[Ruby] [Test code learning/output]

1 minute read

▼This curriculum describes the test code of the application created in the curriculum of the previous chapter.

[Ruby] Understand migration in rails

2 minute read

Introduction While studying Ruby on Rails, I lost track of various words and concepts regarding data manipulation, so I will organize it as a memorandum.

[Ruby] Ruby: How to use cookies

less than 1 minute read

I did the same thing with PHP. How to use jquery-cookie Perl: How to use cookies PHP: How to use cookies Python3: How to use cookies

[Java] Portfolio (Toretomo) Commentary

3 minute read

App overview It is an application that allows you to search for your ideal gym from the area you live in (currently only the wards in Osaka city) or categor...

[Ruby] I made an API client for Nature Remo

1 minute read

Introduction I recently started using Nature Remo and found it useful, so I made a gem called nature_remo_api of Nature Remo’s API Client. This is my first ...

[Ruby] Commands often used on heroku

3 minute read

heroku is a tool that allows you to deploy apps to production environments for free. It’s fairly easy to deploy, so it may be overwhelming after you’ve expe...

[Ruby] [Ruby on Rails] 1 model CRUD (Routing main)

11 minute read

The reason for writing this article Recently I started answering questions with tetatail to deepen my understanding of rails. Looking at the question, some ...

[Ruby] What is Ruby 2D array?

2 minute read

What is a two-dimensional array? A two-dimensional array is an array that has an array as an element.

[Java] What is Java Encapsulation?

6 minute read

What is encapsulation? A function that restricts access to the fields and methods of a class. It has a role to prevent fields and methods from being used fo...

[Ruby] Intermediate table is saved by assign_attributes

2 minute read

-When you want to save the value after receiving the value from the input form, validating it, etc., once you use assign_attributes to update the variables ...

[Java] How to output Java string to console screen

less than 1 minute read

Command to display a character string on the console screen There are two types of instructions to display a character string on the console screen in Java.

[Java] How to check if the content of fixed length string

less than 1 minute read

String sti = ""; // trim space // As a result, is it blank if(sti.trim().isEmpty()) { System.out.println("blank"); }else { System.out.println("notBlank"); }

[Ruby] Extract character from Ruby string slice method

3 minute read

What is the # slice method? The slice method is a method that extracts the character of the condition specified by the argument from the character string.

[Ruby] [ruby] Drill output

less than 1 minute read

Content Question 1 Let’s create a function to enter a name. If there are periods (.) or spaces other than the name, an error will be displayed.

[Java] Template Method pattern

1 minute read

rough template method A design pattern that defines the processing framework in the superclass and the specific contents in the subclass is called Template ...

[Ruby] Ruby/rexml: Rotate each with same name element

1 minute read

What you wanted to do From xml file provided by JMA with Ruby rexml I’m trying to get the warning information and make some judgment according to the situat...

[Java] Java Combining search types that you often search

less than 1 minute read

Summary of type conversions I often search for Type conversion between numeric types int type → double type int num = 3; double number = (double)num; doubl...

[Ruby] Encoding when you get it on Windows + Ruby

1 minute read

First post I think it’s a very small story, but I was lost for a long time with unexpected information. I will gradually participate in qiita from such a pl...

[Ruby] [ruby] Drill output

less than 1 minute read

Content Implementation Comment With input.each_with_index, the numbers stored in input are taken out as num one by one, and numbered in the order in which...

[Java] What is JPA Auditing

2 minute read

What is JPA Auditing When mapping Domain to RDBS table using JPA, there are fields and columns that have Domain in common.

[Ruby] Various Ruby string operations

less than 1 minute read

Introduction Keep a record of the problems that were solved and the answers to study the string manipulation method of Ruby.

[Ruby] Try Cocoa from Ruby

less than 1 minute read

Try Cocoa (macOS API) from Ruby. There used to be RubyCocoa. It seems to be stuck now. There is a gem package called cocoa that is close. https://github.com...

[Ruby] Terminal does not start

less than 1 minute read

Is there something like this? I typed rails s in the terminal

[Java] Iterator pattern

2 minute read

The role of Iterator The role of scanning elements in order

[Ruby] I tried to link AWS I oT button and Slack

3 minute read

Introduction I made a Slack notification button using AWS IoT button. Actually, I made it more than half a year ago, but I could not publish the article ...

[Java] Eclipse refactoring summary

14 minute read

Eclipse has various refactoring functions, but honestly, many of them do not know what happens when they are executed, so I summarized them.

[Java] Assign evaluation result to Java variable

less than 1 minute read

The code that assigns the evaluation result to a variable was hard to understand, so I put it all together to keep my head organized.

[Ruby] About regular expressions in Ruby

3 minute read

Regular expressions in Ruby Regarding the regular expressions I learned in the curriculum the other day, I was in a state where “a lot of ciphers were writt...

[Java] [spring] Let’s use Spring Data JPA

1 minute read

I had some experience with java, When I look at the source code that includes the framework (^o^)/<”What this” was, and I often stopped, so I wrote about it.

[Java] [Java]Spring Boot + Doma2 + H2

less than 1 minute read

公式チュートリアルやってみた。 https://github.com/domaframework/doma-spring-boot

[Ruby] What is self

less than 1 minute read

What is #self The object itself. Inside the method, the instance to which the method belongs can be referenced by a pseudo variable named self. This in othe...

[Java] Perform paiza skill check

less than 1 minute read

I decided to use paiza, which is frequently used personally because of the large number of problems in implementing Java programming problems. paiza has ski...

[Ruby] mysql2 not installed with bundle install

less than 1 minute read

Introduction I get an error every time in my local environment so make a note of the solution *I don’t know the exact cause yet, but this is the content tha...

[Java] Moving CICS-Java applications-(5) using JCICSX

15 minute read

Introduction CICS Transaction Server provides a class library called JCICS to use CICS functions from Java. This is the Java version of the so-called EXEC C...

[Ruby] Knowledge required to give Rails app to AWS

2 minute read

Introduction This is a summary of the minimum knowledge necessary for an author who has no programming experience to submit a Rails application to AWS.

[Ruby] Hash

less than 1 minute read

How to take out the #key ```ruby h = {“apple” => “red”}

[Java] Finding out about Java learning

1 minute read

Work experience in Java is less than 1 year. Having a good experience with other languages makes me feel like learning another language or trying the if sta...

[Ruby] [ruby] Drill output

2 minute read

Content Implementation Comment This time, I created a program that adds numbers 1 to 10 in order. Below is the code I tried first. The following is the o...

[Ruby] [Rails] Get UserAgent with controller

less than 1 minute read

What is UserAgent? UserAgent is the information about the WEB usage environment included in the HTTP request header. It includes information such as browser...

[Ruby] What is @ (instance variable)

less than 1 minute read

What is #@ variable? Variables starting with an at sign are called “instance variables” and can be referenced from your class or subclass. What is an instan...

[Ruby] Twitter marketing? Should it be automated?

2 minute read

It is Abe who released the service around this time. Although I have given too many titles, I am having a hard time not knowing the marketing. For the time ...

[Java] RXTX doesn’t work? Alternative method?

7 minute read

Serial communication after a long time I thought about trying serial communication with Java for the first time in a long time, and I did various research. ...

[Ruby] Realize 3-digit separation display in Ruby

less than 1 minute read

When you want to display #3 digits Use to_s(:delimited) method Add require at the beginning of the file to use the above method active_support is a com...

[Java] Maven goal types

less than 1 minute read

Introduction Maven executes the build based on the pom.xml build tool for Java. Describes the command.

[Ruby] How to decide the parallel number of parallel

less than 1 minute read

I made a note because I investigated how to determine the parallel number of parallel. The number of parallels is determined by evaluating from 1 below.

[Ruby] [ruby] Drill output

less than 1 minute read

Content rewriting from if to unless

[Java] [Java] Create and apply slide master

2 minute read

PPT Master has a powerful template feature that allows users to design slide title text, background image, theme color, etc. according to their needs. After...

[Java] [For newcomers] Introduction to JUnit

17 minute read

I wanted to introduce JUnit for newcomer education for a long time, but it was a disappointing article because I had a little volume when I was writing a dr...

[Ruby] Ruby text conversion

less than 1 minute read

Convert a PHP program using Ruby. EUC_JP and CP51932 are mixed as the character code of PHP. Python cannot handle CP51932, so I wrote it in Ruby.

[Ruby] Rails reference type creation added

1 minute read

Introduction This time, there are cases where reference type is handled when migrating with rails, so I will summarize it.

[Java] Install on Lombok Mac (use STS)

less than 1 minute read

Install Lombok on SpringToolSuite4. I would like to make a note when using Lombok with STS of MAC.

[Ruby] Zero database design until Secretsantas

less than 1 minute read

Database design Notes: For many-to-many, a foreign key in the intermediate table In case of many-to-one, foreign key

[Ruby] What is a Ruby module?

1 minute read

What is a module? A module is a collection of processes.

[Java] Throw a PATCH request with HttpURLConnection

2 minute read

When I wanted to perform API communication when creating an Android application, I had to translate it and implement it without using the OSS library. There...

[Java] How to specify id attribute in JSF

7 minute read

-Environment -CentOS Linux release 7.8.2003 (Core) -Eclipse IDE for Enterprise Java Developers.Version: 2020-03 (4.15.0) -openjdk version “11.0....

[Ruby] Flash message using devise

1 minute read

Description using # haml When you sign in or log out, you can display a message such as “Login.” “Logged out.” If you use devise, the message to be displaye...

[Ruby] [CircleCI] Incorporate circleCI into Rails app

1 minute read

Thing you want to do When you push, run test and notify slack of success or fail. When merged to master, after doing 1, run deploy job and notify slack...

[Java] JVM(Java Virtual Machine)とは?

5 minute read

What is JVM (Java Virtual Machine) JVM is an abbreviation of Java Virtual Machine, which is software required to run Java programs. An entity that can ...

[Java] Java exercises [Basic]

7 minute read

I started solving exercises to study Java. I’m sorry if I’m wrong.

[Java] I tried to make a simple block break

16 minute read

Introduction For the first time today, I will post to Qiita. To be honest, I am confused as to what to do below, but for the time being, I would like to pos...

[Java] I fell into Java Silver (crying)

3 minute read

I recently took the Java Silver test. The result is “64%”… (Pass if 65% or more) Fah! ! ? Shock! ! 1% difference or magical yo… If you have one more correct...

[Java] Button repeated hit prevention code

less than 1 minute read

Personal note ・Code for preventing repeated button hits *For reference, please verify by yourself. (Because of insufficient verification)

[Ruby] About Ruby exception handling

5 minute read

What is exception handling? By performing exception processing, you can identify the cause of the error, the location of the error, and perform appropriate ...

[Ruby] [Rails] I fully understood form_with

1 minute read

Content of this article Different use of form_with method Handling of strong parameters accordingly How to make form contents HTTP communication

[Java] [My memo] About Spring framework

less than 1 minute read

Self-introduction This is my first year as a working adult who has just studied Java. I use the spring framework in my work, so I have summarized it as a me...

[Java] [Java] split method

less than 1 minute read

The split method is By dividing the delimiter string defined by String, Divide into an array of strings. (Split the string at the position that matches the ...

[Ruby] Use Ruby with Google Colab

3 minute read

I tried running Ruby on Google Colab was not working as it is as of July 2020, so I tried trial and error using Julia’s example. I will introduce it because...

[Java] Use jetty with Maven to check the operation.

less than 1 minute read

Introduction When using eclipse to check the operation of a dynamic file, it only works on that terminal. So, check the operation using jetty. And personall...

[Ruby] syntax error [each do end error]

less than 1 minute read

Say “syntax error”, Iterative processing of Ruby If something is missing I get an error!

[Ruby] Manage version of Ruby itself with rbenv

less than 1 minute read

What is this? This is a memo when installing via the Version management tool when installing Ruby. Installed on Ubuntu.

[Ruby] Make a family todo list with Sinatra

less than 1 minute read

Introduction @kirinri posted Lovely article-Qiita, so try to ride it. Completion screen Devised points When you delete a user, delete Todo for that user

[Ruby] How to solve PayPal Ruby SDK SSL_connect error

2 minute read

Introduction Recently, I got an error in PayPal Ruby SDK, but the solution is that there is no Japanese information in Google search, and English is hardly ...

[Java] How to minimize Java images

6 minute read

In this article, I’ll use a Java application based on Spring Boot as an example to give you some general tips for minimizing your Java images.

[Java] Calendar related

less than 1 minute read

```java Calendar c = Calendar.getInstance(); c.add(Calendar.YEAR, -1); c.set(Calendar.HOUR_OF_DAY, 0); c.set(Calendar.MINUTE, 0); c.set(Calendar.SECOND, 0);

[Ruby] About Rails routing

5 minute read

Overview I have summarized routing in a Rails application.

[Ruby] [ruby] Drill output

less than 1 minute read

Content Writing code using the concept of classes and instances Make an addition to the above code to get the following output. However, we will use the cl...

[Java] [Java] Creating a calculator program 1

less than 1 minute read

Purpose About a month has passed since I first learned Java by myself, and I want to create a GUI application using Java, so I will create a calculator appl...

[Ruby] When reading the source code

less than 1 minute read

When you enter an existing project, you need to check what kind of method each Class has.

[Java] Sending an email using Amazon SES SMTP in Java

4 minute read

When the member forgets the login password, I wanted to send an email to the registered email address and press the link in it to reset the password, so sen...

[Ruby] Production environment and credentials.yml.enc

2 minute read

What I want to convey in this article Before dealing with confidential information in the production environment with credentials, please check. Just copy a...

[Ruby] How to implement ranking function with Rails

less than 1 minute read

Previously, I implemented the ranking function by referring to this article of Qiita (Rapid ranking function) was. I was able to implement it safely, but I ...

[Ruby] About object-oriented inheritance and yield Ruby

4 minute read

About inheritance It seems that there is an object-oriented ability to inherit. You can use it without writing the contents of the class definition, or you ...

[Ruby] [ruby] Double hash

less than 1 minute read

Content Code in Ruby so that only the names of all users are output from the double hash! However, the output result is as follows.

[Ruby] [rails] How to create partial template

1 minute read

What is a partial template? A “partial template” is a View file that can be shared by multiple pages. By collecting the code that is duplicated in multiple ...

[Java] [Java] Create a Minecraft Mod 1.14.4 [Introduction]

7 minute read

TL;DR ・I want to create something that has a “moving” feeling ・Let’s try the popular game Minecraft MOD creation! ・It’s ideal because it’s surprisingly easy...

[Java] [Algorithm] Budget

1 minute read

Problem description In order to support the goods needed by each department, Company A examined how much each department needed to buy goods. However, we ca...

[Ruby] Set [rails] validation

less than 1 minute read

What is validation It is a function to check whether the corresponding column contains data when receiving the parameter.

[Java] Java adds hyperlink to Word document

1 minute read

Typically, when editing a Word document, inserting hyperlinks to specific text or images will allow users to quickly jump to other target locations or web p...

[Ruby] Error handling with Graphql-ruby

2 minute read

Introduction Recently, I have implemented an API with graphql-ruby. So I sought best practices for error handling in graphql. I have just started, so there ...

[Java] Display hello world with spring + gradle

3 minute read

In Construct Java environment and output helloworld, I wrote helloworld to the console. This time, let’s go a little further and display HTML in the spring ...

[Java] Coordinating API with Spring+Vue.js

4 minute read

Introduction This time, create RestAPI with Spring framework, The goal is to display the data with Vue.js. (The initial environment setup such as Java insta...

[Java] [Java] Get List/Map elements with Iterator

3 minute read

table of contents at first What is Iterator List Iterator Map Iterator From generic expression to extended for statement Summary in conclusio...

[Java] [Algorithm] Addition of digits

less than 1 minute read

Problem description Create a solution method that receives a natural number N, adds each digit of N, and returns. **Example) When N=123, 1 + 2 + 3 = 6 is re...

[Ruby] Writing class inheritance in Ruby

1 minute read

I will write the method of inheriting and using the method defined in the parent class in other new classes.

[Ruby] Post videos with rails

1 minute read

This time I will post for the first time. Please understand that it may be difficult to see.

[Java] Getting started with Android!

10 minute read

Introduction Hello, end of school this week full, spend the summer vacation with no contents from next week is my. This time, I would like to try HTTP commu...

[Ruby] About conditional branching of rails development

2 minute read

rails Development of conditional branch I have summarized a good description that it is web application development with rails! I want to be able to edit/de...

[Ruby] [Today’s stack #1] Until on rails on cloud9

1 minute read

result This article (Https://skillhub.jp/courses/134/lessons/785) Based on, I moved the rails server on cloud9 and completed until I saw the screen of “Yay!...

[Ruby] Writing keys and values in Ruby

less than 1 minute read

Based on the 3 types of reference, the types of key and value are summarized below.

[Ruby] Ruby Hash memo

less than 1 minute read

Reference This is a memo for yourself when you do not know the hash of ruby. If you make a mistake, please comment. Environment ruby 2.7.1 Definition Can be...

[Ruby] Ruby exception handling

less than 1 minute read

background It was necessary to use it properly depending on the situation when drawing the exception handling of Ruby, so I summarized it as a memorandum. ...

[Ruby] How to configure routing with [rails]resources

less than 1 minute read

Set routing with #resources The routing can also be set individually. However, since the seven basic actions in rails are often used during development, Set...

[Ruby] [rails]Strong Parametersとは?

less than 1 minute read

What is #Strong Parameters Strong Parameters is a mechanism for improving the security added from Rails 4 series. A security measure that prevents the execu...

[Ruby] [rails]devise cannot be registered/logged in

less than 1 minute read

Cannot register/login with #devise After creating user registration and login screen with devise, This method is for when you want to register/login with in...

[Ruby] [Rails] Prepare dummy data for testing [Faker]

1 minute read

Introduction When testing with RSpec etc., we may prepare data in advance with FactoryBot etc., but at that time, I will write about how to use Faker which ...

[Ruby] [rails] devise view page edit is not reflected

less than 1 minute read

Edit of view page created with #deivse is not reflected After editing the default login page with devise and checking the screen, I’ve encountered a problem...

[Java] [Algorithm] N numbers with intervals of X

less than 1 minute read

Problem description The method solution takes a parameter of integer x and a natural number n and returns a list with n numbers starting from x and incremen...

[Java] [Algorithm] Descending order of character strings

less than 1 minute read

Problem description Create a method solution that receives the parameter of the character string s, sorts in descending order and returns a new character st...

[Ruby] List of actions defined in [rails]Controller

less than 1 minute read

List of actions defined in #Controller Rails uses actions that have the following seven roles that are the basis of web applications.

[Java] JavaFX dropbox update delay issue

1 minute read

Overview JavaFX ChoiceBox instance (I expect the same for ComboBox) Occurs when swapping the alternative list of Latency and increased memory usage were iss...

[Java] igv memory settings

2 minute read

what happened Can’t open a file on a memory loading machine due to an out of memory error? ? ? ?

[Java] Use PlantUML with Visual Studio Code

less than 1 minute read

Preference is important Install JAVA and set PATH Setting the path of Oracle Java https://java.com/ja/download/win10.jsp (I also installed Java SE Deve...

[Java] use enum instead of int constant

1 minute read

int enum pattern Poor expressiveness. Passing Apple to Methods Expecting Orange The compiler doesn’t get offended when comparing Apple and Orange with the =...

[Java] Java diary

less than 1 minute read

⭕️Spring⭕️ A little summary of what I learned today!

[Java] Image upload function with Vue.js + Flask

2 minute read

Overview This time, I will make an image recognition application using Vue.js for the front end and Flask for the back end. For the time being, this time we...

[Java] [Java] Superclass/Subclass constructors

3 minute read

table of contents Introduction Prerequisite knowledge -About inherited classes -Constructor This time -Implicit constructor execution in conc...

[Java] Android Detects pinch-in and pinch-out

3 minute read

Introduction Hello. This time, I will detect the pinch operation with Android. I will explain how to distinguish between pinch-in and pinch-out.

[Java] How to make Burp Suite extensions

1 minute read

It is a post of (almost) daily Qiita article. It is quite difficult to write every day, so it may be better to put together URLs of information of interest ...

[Java] HashMap and HashSet classes

1 minute read

HashMap class HashMap is a collection that can manage a collection of elements that have a set of keys and values.

[Java] ArrayList class

less than 1 minute read

Use an ordinary array after deciding how many elements to store.

[Java] About Records added in preview in Java JDK 14

1 minute read

Introduction Java is also fast and JDK15 will be released soon! (Scheduled for September 2020) However, it was honest that the JDK 14 just before that didn’...

[Ruby] [Ruby] I made a simple Ping client

2 minute read

Overview I tried to make a simple client that sends and receives ICMP Echo Request only once, so before I forget it, I memorized what I learned during imple...

[Ruby] [Rails] About active hash

less than 1 minute read

What is Active Hash A gem that allows you to manipulate hashed values like Active Record It is convenient because you can also attach a Relation

[Java] @quantity

less than 1 minute read

https://www.it-swarm-ja.tech/ja/java/spring-boot%E3%81%AF2%E3%81%A4%E3%81%AE%E3%83%87%E3%83%BC%E3%82%BF%E3%82%BD%E3%83%BC%E3%82%B9%E3%82%92%E8%A8%AD%E5%AE%9...

[Ruby] Rails Tutorial cheat sheet

4 minute read

“I did a Rails Tutorial, but after two weeks I can’t remember what I did.”

[Ruby] I want to delete files managed by Git

less than 1 minute read

When I forget to write it in .gitignore and commit it, “Adding to .gitignore is all right…” Do you misunderstand that? Like me.. sweat

[Ruby] Getting started with Ruby

4 minute read

irb Interactive execution environment Check object type ”Character string” (receiver).class → String 1.class → Integer check object_id “String”.object_id → ...

[Ruby] Getting started with Ruby 2

2 minute read

initialize When an object is created with the new method, the initialize method of that object is executed

[Java] Format and serialize nicely in Jackson

less than 1 minute read

When I want to serialize to JSON in Java, I often use Jackson because JSON-B is not powerful enough, but I always forget how to write it, so it is a memo.

[Java] [Rails] JavaScript-related tests

1 minute read

Introduction In the test with Capybara, you need to change the setting a little if you want to process JavaScript. As a simple example, let’s test the proce...

[Java] Self-made by Spring

2 minute read

background Make a note of the validation method other than adding annotations to the Form (double check, etc.). This time use Spring Validator instead of Be...

[Ruby] Make a typing game with ruby

1 minute read

Hello. This time I’m going to make a typing game with Ruby. If you want to try it for the time being, please try it from here.

[Java] I want to determine the range using the month

less than 1 minute read

problem I want to get it before September when I have monthly data, Since January, February, and March are data for the next year, I think there is somethin...

[Ruby] I tried FizzBuzz.

1 minute read

Overview In Ruby,, FizzBuzz Display 1 to 100 variables, of which For the value divisible by 3, use the string “Fizz” For the value divisible by 5, use the c...

[Ruby] Chat app production

less than 1 minute read

We have created a chat app to spread the knowledge of individual learning.