[JAVA] Implement a simple Web REST API server with Spring Boot + MySQL

Outline Implement a REST API server using Spring Boot from scratch. YutaKase6/spring-api-sample

Goal Entry Point Create an API with the following entry points.

table

Physical name	Logical name
id	User ID
value	User information

Steps...

First, create a project

Create a Spring Boot project using IntelliJ (Spring Initializr) --Qiita

Check about Gradle

A little research on Gradle and read the build.gradle generated by Spring Initializr --Qiita

Think about architecture and class design before implementation

Consider the architecture of Web API implemented by Spring Boot --Qiita

I will implement

Implementing REST API with Spring Boot and JPA (domain layer) --Qiita Implementing REST API with Spring Boot and JPA (Infrastructure Layer) --Qiita Implementing REST API with Spring Boot and JPA (Application Layer) --Qiita

MySQL settings

MySQL preparation

Install & Start

% brew install mysql
% mysql.server start

** Create table **

CREATE TABLE test_users (
  id VARCHAR(18) PRIMARY KEY
  , value TEXT DEFAULT NULL
  , created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
  , updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=utf8
;

mysql> desc test_users;
+------------+-------------+------+-----+-------------------+-----------------------------+
| Field      | Type        | Null | Key | Default           | Extra                       |
+------------+-------------+------+-----+-------------------+-----------------------------+
| id         | varchar(18) | NO   | PRI | NULL              |                             |
| value      | text        | YES  |     | NULL              |                             |
| created_at | timestamp   | NO   |     | CURRENT_TIMESTAMP |                             |
| updated_at | timestamp   | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+------------+-------------+------+-----+-------------------+-----------------------------+
4 rows in set (0.00 sec)

Spring Boot settings

Write the settings in src / main / resources / application.properties. You can write in yml, so write in yml. First of all, rename.

Write the connection settings with MySQL.

`application.yml`


spring:
  datasource:
    url: jdbc:mysql://localhost:3306/<SchemaName>
    username: root
    password:

  jpa:
    hibernate:
      ddl-auto: none

Operation check

Run

** Run from IntelliJ (Part 1) ** It can be executed by pressing the play button on the left of the main method.

** Run from IntelliJ (Part 2) ** You can select the main class from the pull-down on the upper right and execute it with the play button on the right.

** Run from Gradle **

% ./gradlew bootRun

** Run from java **

% ./gradlew build
% java -jar build/libs/spring-api-0.0.1-SNAPSHOT.jar

Normal confirmation

--Registration

% curl -X POST "http://localhost:8080/v1/users" -H "Content-Type: application/json" -d "{ \"id\": \"id\", \"value\": \"value\"}" -s -w '\nstatus code: %{http_code}\n'

{"id":"id","value":"value"}
status code: 201

--Reference

% curl "http://localhost:8080/v1/users/id" -s -w '\nstatus code: %{http_code}\n'

{"id":"id","value":"value"}
status code: 200

Delete

% curl -X DELETE "http://localhost:8080/v1/users/id" -s -w '\nstatus code: %{http_code}\n'


status code: 204

Abnormality check (Spring Boot default)

--Non-existent user

% curl "http://localhost:8080/v1/users/hoge" -s -w '\nstatus code: %{http_code}\n'

{"timestamp":"2018-07-20T12:11:51.131+0000","status":500,"error":"Internal Server Error","message":"No message available","path":"/v1/users/hoge"}
status code: 500

--Undefined methods

% curl "http://localhost:8080/v1/users" -s -w '\nstatus code: %{http_code}\n'

{"timestamp":"2018-07-20T12:14:08.013+0000","status":405,"error":"Method Not Allowed","message":"Request method 'GET' not supported","path":"/v1/users"}
status code: 405

--Undefined path

% curl "http://localhost:8080/v1/user" -s -w '\nstatus code: %{http_code}\n'

{"timestamp":"2018-07-20T12:14:14.668+0000","status":404,"error":"Not Found","message":"No message available","path":"/v1/user"}
status code: 404

There are many others.