[VSCode] Try Java

Intro

I will try writing Java with VSCode.
In this time, I won't use build tools like Maven, Gradle, etc.
And I will use Amazon Corretto.

• Amazon Corretto

Creating a Java project without any build tools

First, I installed "Extension Pack for Java" into my VSCode.

• Extension Pack for Java - Visual Studio Marketplace

• Extension Pack for Java

• Java in Visual Studio Code

After installing, I create a Java project by Ctrl + Shift + P -> "Java:Create Java Project...".
After creating, the project has four folders and four files.

JavaSample
  L.vscode
    Lsettings.json
  Lbin
    LApp.class
  Llib
  Lsrc
    LApp.java
  LREADME.md

Changing build settings

I can change building settings for Java from settings.json.

settings.json

{
    "java.project.sourcePaths": ["src"],
    "java.project.outputPath": "bin",
    "java.project.referencedLibraries": [
        "lib/**/*.jar"
    ]
}

Stopping auto compile

By default, when I change Java files, the compiler will recompile automatically.
But in some cases, I want to stop it.

To do this, I add "java.autobuild.enabled".

settings.json

...
    ],
    "java.autobuild.enabled": false
}

Changing default file encodings

By default, VSCode open files with UTF-8 encoding.
But in some cases, I want to change it for specific projects.

Adding "files.encoding" changes the default file encodings for the project.

settings.json

...
    "java.autobuild.enabled": true,
    "files.encoding": "shiftjis",
}

Creating a Springboot project

To create Springboot projects, I installed "Spring Boot Extension Pack" and "Gradle for Java".

• Spring Boot Extension Pack - Visual Studio Marketplace
• Gradle for Java
• Maven and Gradle support for Java in Visual Studio Code

I selected Gradle as the build tool and I didn't add any dependencies.

build.gradle

plugins {
    id 'java'
    id 'org.springframework.boot' version '3.1.5'
    id 'io.spring.dependency-management' version '1.1.3'
}

group = 'jp.masanori'
version = '0.0.1-SNAPSHOT'

java {
    sourceCompatibility = '17'
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

tasks.named('test') {
    useJUnitPlatform()
}

SpringbootsampleApplication.java

package jp.masanori.springbootsample;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringbootsampleApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootsampleApplication.class, args);
    }
}

Adding a controller class

To create Web API, I added "org.springframework.boot:spring-boot-starter-web" into build.gradle.

build.gradle

...
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
...

Because Springboot automatically maps URLs through annotations, so I just need to add a controller class.

HomeController.java

package jp.masanori.springbootsample;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HomeController {

    @GetMapping("/hello")
    public String hello(@RequestParam(value = "name", defaultValue = "World") String name) {
      return String.format("Hello %s!", name);
    }
}

• Spring Quickstart Guide