[Java] Creating a Spring Boot application using IntelliJ IDEA

4 minute read

This is the procedure up to the point where you create a Spring Boot application using IntelliJ IDEA and execute it. Make sure you can run the debug in IntelliJ IDEA and build it into a JAR file and run it.

Development environment

  • macOS Caralina 10.15.4
  • OpenJDK 14.0.2
  • maven 14.0.1
  • IntelliJ IDEA

Advance preparation

Please prepare the following to develop Spring Boot.

  • Download and install OpenJDK https://openjdk.java.net/
  • Download and install Maven https://maven.apache.org/download.cgi
  • Download and install IntelliJ IDEA https://www.jetbrains.com/ja-jp/idea/
  • Confirm path
  • java -version
  • mvn -v

Spring Boot development with IntelliJ IDEA

Create a project according to the contents of Getting Started of Spring Boot.

https://spring.pleiades.io/spring-boot/docs/current/reference/html/getting-started.html#getting-started-first-application

Follow the steps below.

  • Create new project
  • create pom.xml
  • Creating a Hello World! application
  • Run a program using IntelliJ IDEA
  • build into jar file and run

Creating a new project

Start IntelliJ IDEA and select “New Project”.

intelliJ_home.png

Select Maven, specify the OpenJDK you installed in the Project SDK, then select Next.

intelliJ_new_project_1.png

Enter a name for your project and select Finish.

intelliJ_new_project_2.png

edit pom.xml

Describe the following contents in pom.xml.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>org.example</groupId>
<artifactId>spring-boot-demo-app</artifactId>
<version>1.0-SNAPSHOT</version>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.2.RELEASE</version>
</parent>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.3.2.RELEASE</version>
</plugin>
</plugins>
</build>
</project>

After editing pom.xml, reload the project.

intelliJ_reload_module.png

Hello World! Application Creation

Create src/main/java/Example.java.

intelliJ_new_file.png

The following contents are described in Example.java.

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.web.bind.annotation.*;

@RestController
@EnableAutoConfiguration
public class Example {

@RequestMapping("/")
String home() {
return "Hello World!";
}

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

}

Run the program using IntelliJ IDEA

Let’s run the created program. Execute the program by pressing the Run button displayed on the left of the main class.

intelliJ_run.png

If the execution is successful, the following message will be displayed on the console.

sh/Library/Java/JavaVirtualMachines/jdk-14.0.2.jdk/Contents/Home/bin/java -javaagent:/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar=52512:/Applications/IntelliJ IDEA CE.app/Contents/bin -Dfile.encoding=UTF-8 -classpath /Users/masayuki/Documents/program/spring-boot-demo-app/target/classes:/Users/masayuki/.m2/repository/org/springframework/boot/spring-boot-starter-web/2.3.2.RELEASE/spring-boot-starter-web-2.3.2.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/boot/spring-boot-starter/2.3.2.RELEASE/spring-boot-starter-2.3.2.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/boot/spring-boot/2.3.2.RELEASE/spring-boot-2.3.2.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/2.3.2.RELEASE/spring-boot-autoconfigure-2.3.2.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/boot/spring-boot-starter-logging/2.3.2.RELEASE/spring-boot-starter-logging-2.3.2.RELEASE.jar:/Users/masayuki/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar:/Users/masayuki/.m2/repository/ch/qos/logback/logback-core/1.2.3/logback-core-1.2.3.jar:/Users/masayuki/.m2/repository/org/slf4j/slf4j-api/1.7.30/slf4j-api-1.7.30.jar:/Users/masayuki/.m2/repository/org/apache/logging/log4j/log4j-to-slf4j/2.13.3/log4j-to-slf4j-2.13.3.jar:/Users/masayuki/.m2/repository/org/apache/logging/log4j/log4j-api/2.13.3/log4j-api-2.13.3.jar:/Users/masayuki/.m2/repository/org/slf4j/jul-to-slf4j/1.7.30/jul-to-slf4j-1.7.30.jar:/Users/masayuki/.m2/repository/jakarta/annotation/jakarta.annotation-api/1.3.5/jakarta.annotation-api-1.3.5.jar:/Users/masayuki/.m2/repository/org/springframework/spring-core/5.2.8.RELEASE/spring-core-5.2.8.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/spring-jcl/5.2.8.RELEASE/spring-jcl-5.2.8.RELEASE.jar:/Users/masayuki/.m2/repository/org/yaml/snakeyaml/1.26/snakeyaml-1.26.jar:/Users/masayuki/.m2/repository/org/springframework/boot/spring-boot-starter-json/2.3.2.RELEASE/spring-boot-starter-json-2.3.2.RELEASE.jar:/Users/masayuki/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.11.1/jackson-databind-2.11.1.jar:/Users/masayuki/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.11.1/jackson-annotations-2.11.1.jar:/Users/masayuki/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.11.1/jackson-core-2.11.1.jar:/Users/masayuki/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jdk8/2.11.1/jackson-datatype-jdk8-2.11.1.jar:/Users/masayuki/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.11.1/jackson-datatype-jsr310-2.11.1.jar:/Users/masayuki/.m2/repository/com/fasterxml/jackson/module/jackson-module-parameter-names/2.11.1/jackson-module-parameter-names-2.11.1.jar:/Users/masayuki/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/2.3.2.RELEASE/spring-boot-starter-tomcat-2.3.2.RELEASE.jar:/Users/masayuki/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/9.0.37/tomcat-embed-core-9.0.37.jar:/Users/masayuki/.m2/repository/org/glassfish/jakarta.el/3.0.3/jakarta.el-3.0.3.jar:/Users/masayuki/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/9.0.37/tomcat-embed-websocket-9.0.37.jar:/Users/masayuki/.m2/repository/org/springframework/spring-web/5.2.8.RELEASE/spring-web-5.2.8.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/spring-beans/5.2.8.RELEASE/spring-beans-5.2.8.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/spring-webmvc/5.2.8.RELEASE/spring-webmvc-5.2.8.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/spring-aop/5.2.8.RELEASE/spring-aop-5.2.8.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/spring-context/5.2.8.RELEASE/spring-context-5.2.8.RELEASE.jar:/Users/masayuki/.m2/repository/org/springframework/spring-expression/5.2.8.RELEASE/spring-expression-5.2.8.RELEASE.jar Example



  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.3.2.RELEASE)

2020-08-02 14:26:02.276  INFO 35892 --- [           main] Example                                  : Starting Example on maa with PID 35892 (/Users/masayuki/Documents/program/spring-boot-demo-app/target/classes started by masayuki in /Users/masayuki/Documents/program/spring-boot-demo-app)
2020-08-02 14:26:02.280  INFO 35892 --- [           main] Example                                  : No active profile set, falling back to default profiles: default
2020-08-02 14:26:04.567  INFO 35892 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2020-08-02 14:26:04.624  INFO 35892 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]2020-08-02 14:26:04.625  INFO 35892 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.37]
2020-08-02 14:26:04.847  INFO 35892 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2020-08-02 14:26:04.848  INFO 35892 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2435 ms
2020-08-02 14:26:05.231  INFO 35892 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2020-08-02 14:26:05.676  INFO 35892 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2020-08-02 14:26:05.703  INFO 35892 --- [           main] Example                                  : Started Example in 4.953 seconds (JVM running for 6.18)

この状態でブラウザでhttp://localhost:8080へアクセスすると、Hello World!が表示されます。

jarファイルにビルドして実行

右側の「Maven」をクリックすると表示されるツリーから、「プロジェクト名」 > 「Lifecycle」 > 「package」を右クリックし、さらに「Run Maven Build」を選択します。

intelliJ_build.png

正しくビルドできた場合は、コンソールに以下のメッセージが表示されます。

/Library/Java/JavaVirtualMachines/jdk-14.0.2.jdk/Contents/Home/bin/java -Dmaven.multiModuleProjectDirectory=/Users/masayuki/Documents/program/spring-boot-demo-app "-Dmaven.home=/Applications/IntelliJ IDEA CE.app/Contents/plugins/maven/lib/maven3" "-Dclassworlds.conf=/Applications/IntelliJ IDEA CE.app/Contents/plugins/maven/lib/maven3/bin/m2.conf" "-Dmaven.ext.class.path=/Applications/IntelliJ IDEA CE.app/Contents/plugins/maven/lib/maven-event-listener.jar" "-javaagent:/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar=52530:/Applications/IntelliJ IDEA CE.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Applications/IntelliJ IDEA CE.app/Contents/plugins/maven/lib/maven3/boot/plexus-classworlds.license:/Applications/IntelliJ IDEA CE.app/Contents/plugins/maven/lib/maven3/boot/plexus-classworlds-2.6.0.jar" org.codehaus.classworlds.Launcher -Didea.version=2020.2 package
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------< org.example:spring-boot-demo-app >------------------
[INFO] Building spring-boot-demo-app 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ spring-boot-demo-app ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ spring-boot-demo-app ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /Users/masayuki/Documents/program/spring-boot-demo-app/target/classes
[INFO] 
[INFO] --- maven-resources-plugin:3.1.0:testResources (default-testResources) @ spring-boot-demo-app ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /Users/masayuki/Documents/program/spring-boot-demo-app/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ spring-boot-demo-app ---
[INFO] Changes detected - recompiling the module!
[INFO] 
[INFO] --- maven-surefire-plugin:2.22.2:test (default-test) @ spring-boot-demo-app ---
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ spring-boot-demo-app ---
[INFO] Building jar: /Users/masayuki/Documents/program/spring-boot-demo-app/target/spring-boot-demo-app-1.0-SNAPSHOT.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:2.3.2.RELEASE:repackage (repackage) @ spring-boot-demo-app ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  9.498 s
[INFO] Finished at: 2020-08-02T14:27:21+09:00
[INFO] ------------------------------------------------------------------------

ビルドした際のコンソールのメッセージに[プロジェクトのルートフォルダ]/target/[プロジェクト名]-1.0-SNAPSHOT.jarを作成したと表示されているので、JARファイルを探しjava -jar [作成されたjarファイル]で起動します。正しく実行できた場合は、コンソールに以下のメッセージが表示されます。

$ java -jar target/spring-boot-demo-app-1.0-SNAPSHOT.jar

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.3.2.RELEASE)2020-08-02 14:27:49.758  INFO 35907 --- [           main] Example                                  : Starting Example on maa with PID 35907 (/Users/masayuki/Documents/program/spring-boot-demo-app/target/spring-boot-demo-app-1.0-SNAPSHOT.jar started by masayuki in /Users/masayuki/Documents/program/spring-boot-demo-app)
2020-08-02 14:27:49.765  INFO 35907 --- [           main] Example                                  : No active profile set, falling back to default profiles: default
2020-08-02 14:27:52.252  INFO 35907 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2020-08-02 14:27:52.306  INFO 35907 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2020-08-02 14:27:52.306  INFO 35907 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.37]
2020-08-02 14:27:52.528  INFO 35907 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2020-08-02 14:27:52.528  INFO 35907 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2622 ms
2020-08-02 14:27:53.043  INFO 35907 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2020-08-02 14:27:53.586  INFO 35907 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2020-08-02 14:27:53.613  INFO 35907 --- [           main] Example                                  : Started Example in 5.628 seconds (JVM running for 6.985)

この状態でブラウザでhttp://localhost:8080へアクセスすると、Hello World!が表示されます。

以上、IntelliJ IDEAを使ってSpring Bootアプリケーションの実行とビルドを確認しました。