The goal of this howto is to get a simple Spring Boot application running on a Raspberry Pi 4.
Install 64-bit OS
Installing RaspiOS Bullseye on the RPi3 or RPi4 is straight forward.
I recommend using the Raspberry Pi Imager.
After getting Bullseye installed, this is my RPi4.
~$ lsb_release -d
Description: Debian GNU/Linux 11 (bullseye)
~$ uname -a
Linux raspberrypi 5.10.63-v8+ #1459 SMP PREEMPT Wed Oct 6 16:42:49 BST 2021 aarch64 GNU/Linux
~$
Install SDKMAN
Install SDKMAN to install and configure a JDK.
~$ sudo apt -q install zip
~$ curl -s "https://get.sdkman.io" | bash
~$ source "$HOME/.sdkman/bin/sdkman-init.sh"
~$ sdk version
~$ ==== BROADCAST =================================================================
* 2022-01-06: connor 1.2.1 available on SDKMAN! https://github.com/helpermethod/connor/releases/tag/v1.2.1
* 2022-01-04: micronaut 3.2.4 available on SDKMAN!
* 2022-01-02: jbang 0.86.0 available on SDKMAN! https://github.com/jbangdev/jbang/releases/tag/v0.86.0
================================================================================
SDKMAN 5.13.1
~$
Install a Java JDK
Install the GraalVM for Java 17, using SDKMAN.
~$ sdk install java 21.3.0.r17-grl
Downloading: java 21.3.0.r17-grl
In progress...
######################################### 100.0%
Repackaging Java 21.3.0.r17-grl...
Done repackaging...
Installing: java 21.3.0.r17-grl
Done installing!
Setting java 21.3.0.r17-grl as default.
~$
This took several minutes to complete on RPi 4
Confirm that java is the correct version.
~$ java -version
openjdk version "17.0.1" 2021-10-19
OpenJDK Runtime Environment GraalVM CE 21.3.0 (build 17.0.1+12-jvmci-21.3-b05)
OpenJDK 64-Bit Server VM GraalVM CE 21.3.0 (build 17.0.1+12-jvmci-21.3-b05, mixed mode, sharing)
~$
Create simple Spring Boot application
Use the Spring Initializer web API to create a simple example.
The parameters below:
- name the artifact
- choose Java 17
- include the "web" and "actuator" dependencies
- use latest version of Spring Boot by default
~$ mkdir demo
~$ cd demo
~/demo $ curl https://start.spring.io/starter.tgz -d groupId=dev.dashaun -d artifactId=spring-pi -d name=spring-pi -d packageName=dev.dashaun.spring-pi -d dependencies=web,actuator -d javaVersion=17 | tar -xzf -
~/demo $ ls
HELP.md mvnw mvnw.cmd pom.xml src
~/demo $
Build the application with Maven
The Spring Initializer includes a recent version of Maven to use for the build.
~/demo $ ./mvnw clean package
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------------< dev.dashaun:spring-pi >------------------------
[INFO] Building spring-pi 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ spring-pi ---
...
...
...
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 25.854 s
[INFO] Finished at: 2022-01-11T18:36:55Z
[INFO] ------------------------------------------------------------------------
~/demo $
Start the embedded web server
The "web" dependency includes an embedded web server that we can now run.
~/demo $ ./mvnw spring-boot:start
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------------< dev.dashaun:spring-pi >------------------------
[INFO] Building spring-pi 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- spring-boot-maven-plugin:2.6.2:start (default-cli) @ spring-pi ---
[INFO] Attaching agents: []
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.6.2)
2022-01-11 18:38:56.137 INFO 13687 --- [ main] d.dashaun.springpi.SpringPiApplication : Starting SpringPiApplication using Java 17.0.1 on raspberrypi with PID 13687 (/home/pi/fun/demo/target/classes started by pi in /home/pi/fun/demo)
2022-01-11 18:38:56.147 INFO 13687 --- [ main] d.dashaun.springpi.SpringPiApplication : No active profile set, falling back to default profiles: default
2022-01-11 18:39:01.051 INFO 13687 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2022-01-11 18:39:01.089 INFO 13687 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2022-01-11 18:39:01.091 INFO 13687 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.56]
2022-01-11 18:39:01.322 INFO 13687 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2022-01-11 18:39:01.323 INFO 13687 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 4958 ms
2022-01-11 18:39:03.347 INFO 13687 --- [ main] o.s.b.a.e.web.EndpointLinksResolver : Exposing 1 endpoint(s) beneath base path '/actuator'
2022-01-11 18:39:03.481 INFO 13687 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2022-01-11 18:39:03.534 INFO 13687 --- [ main] d.dashaun.springpi.SpringPiApplication : Started SpringPiApplication in 8.781 seconds (JVM running for 11.137)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 15.003 s
[INFO] Finished at: 2022-01-11T18:39:03Z
[INFO] ------------------------------------------------------------------------
~/demo $
Our applicaiton is now running on port 8080
Install 'jq'
Install 'jq' first, to format the output.
~/demo $ sudo apt install -yq jq
Call the Spring Boot actuator endpoint
The included the "actuator" dependency provides endpoints to test with.
~/demo $ curl -fsSL localhost:8080/actuator | jq .
{
"_links": {
"self": {
"href": "http://localhost:8080/actuator",
"templated": false
},
"health": {
"href": "http://localhost:8080/actuator/health",
"templated": false
},
"health-path": {
"href": "http://localhost:8080/actuator/health/{*path}",
"templated": true
}
}
}
~/demo $ curl -fsSL localhost:8080/actuator/health | jq .
{
"status": "UP"
}
~/demo $
Summary
For this example we are using a Raspberry Pi 4 to run Spring Boot 2.6.2 using Java 17 on the Raspberry Pi!
Even though we are using the GraalVM for this example we are not generating a native application.
We will containerize this application into a native image, in a follow up article.
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