[JAVA] How to set Spring Boot + PostgreSQL

Note

Overview

--Enable PostgreSQL with Spring Boot --Make a simple app

• Detailed explanation of how it works is omitted.

environment

--SpringToolSuite 3.8.4 (hereinafter STS)

• SpringBoot 1.5.3.RELEASE
• PostgreSQL v9.3

Premise

--Spring Tool Suite installed --PostgreSQL has already been installed (this time, the one installed in the host OS is used)

procedure

1. DB settings
2. Create a project
3. Project settings
4. Create a model controller repository service
5. Run

Preparation

Create a DB in advance before creating a project

PostgreSQL

CREATE DATABASE testdb;
 (Don't forget to switch databases)
CREATE TABLE person (
id SERIAL PRIMARY KEY
, name VARCHAR(16)
, age INT);
 
INSERT INTO person VALUES
 (1,'taro',19)
 , (2,'tadokoro',24)
 , (3,'hanako',14);

Introduction

Create a new project

Create a project using Spring Initializr

Press the Generate Project button to download the project folder. Then ** unzip ** and leave it wherever you like

Project import

Select the [Directory] button from the File-> Open Projects From File Systems .. on the STS tab and select the project folder you just unzipped. Make sure Import as is Maven and select Finish

• If Import as is Eclipse, decompress it again or change the decompression method and select the project.

Environmental setting

Rewriting pom.xml

Access Spring IO platform Copy the settings description in QuickStart and add it to your pom.xml

/bootpostgres/pom.xml

～～～
</properties>

<!--from here-->
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>io.spring.platform</groupId>
            <artifactId>platform-bom</artifactId>
            <version>Brussels-SR2</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>
<!--So far-->

<dependencies>
  <!--Also add the following-->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
  </dependency>
  <!--Add up to here-->
～～～

Add connection information to PostgreSQL

/src/main/resources/application.properties

spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.url=jdbc:postgresql://localhost:5432/testdb
spring.datasource.username=postgres
spring.datasource.password=hogehoge

That's all for environment settings

Creating a model

java:src/main/java/com.takahashi.Person.java/

@Entity
@Table(name = "person")
public class Person {

  @Id
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  private int id;
  
  @Column(name="name")
  private String name;
  
  @Column(name="age")
  private int age;

  public Integer getId() {
    return id;
  }
  public void setId(Integer id) {
    this.id = id;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
}

Creating a repository

java:/src/main/resources/com.takahashi.PersonRepository.java

@Repository
public interface PersonRepository extends JpaRepository<Person,Integer>{

}

Creating a service

java:/src/main/resources/com.takahashi.PersonService.java

@Service
@Transactional
public class PersonService {

  @Autowired
  PersonRepository repository;
  
  public List<Person> findAll(){
    return repository.findAll(new Sort(Sort.Direction.ASC,"id"));
  } 
}

Creating a controller

java:/src/main/resources/com.takahashi.PersonController.java

@RestController
@RequestMapping("/person")
public class PersonController {
  
  @Autowired
  PersonService service;
  
  @RequestMapping(value="/",method=RequestMethod.GET)
  public List<Person> index(){
    return service.findAll();
  }
  
}

Execute

Select a project and right click Run as -> Spring Boot App

If it is displayed as above, it is OK

Reference site

https://www.slideshare.net/shintanimoto/spring-boot10 http://dev.classmethod.jp/server-side/java/using_spring_boot_2/

Sample project

https://github.com/aiue1500/bootpostgres