Spring Boot Banner Customization: banner.txt, Colors, Disable

// Default Spring Boot banner output at startup:
//
//   .   ____          _            __ _ _
//  /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
// ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
//  \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
//   '  |____| .__|_| |_|_| |_\__, | / / / /
//  =========|_|==============|___/=/_/_/_/
//
//  :: Spring Boot ::                (v3.5.0)      <- your version
//
// Where it happens:
//   SpringApplication.run() -> printBanner(environment)
//   SpringApplicationBannerPrinter.print(...)
//   fallback when nothing else is configured: SpringBootBanner

  __  __        _
 |  \/  |_  _  /_\  _ __ _ __
 | |\/| | || |/ _ \| '_ \ '_ \
 |_|  |_|\_, /_/ \_\ .__/ .__/
         |__/      |_|  |_|

 ${spring.application.name:My Application}
 Version     : ${application.formatted-version}
 Spring Boot : ${spring-boot.formatted-version}
 Java        : ${java.version}
 Profile(s)  : ${spring.profiles.active:default}

# Show the effect of defaults — banner.txt:
#   Version : ${application.version}              -> "1.0.0" from a jar, blank from the IDE
#   Profile : ${spring.profiles.active:default}   -> "default" when no profile property is set
#   Port    : ${server.port:8080}                 -> value of server.port, or 8080

# Unresolved placeholders are printed literally:
#   Region : ${deploy.region}                     -> prints: ${deploy.region}
#   Region : ${deploy.region:unknown}             -> prints: unknown

${AnsiColor.BRIGHT_CYAN}
 ███╗   ███╗██╗   ██╗ █████╗ ██████╗ ██████╗
 ████╗ ████║╚██╗ ██╔╝██╔══██╗██╔══██╗██╔══██╗
 ██╔████╔██║ ╚████╔╝ ███████║██████╔╝██████╔╝
 ██║╚██╔╝██║  ╚██╔╝  ██╔══██║██╔═══╝ ██╔═══╝
 ██║ ╚═╝ ██║   ██║   ██║  ██║██║     ██║
 ╚═╝     ╚═╝   ╚═╝   ╚═╝  ╚═╝╚═╝     ╚═╝
${AnsiColor.DEFAULT}
${AnsiColor.BRIGHT_WHITE} :: My Application ::${AnsiColor.DEFAULT}
${AnsiStyle.BOLD}   Version     :${AnsiStyle.NORMAL} ${application.formatted-version}
${AnsiStyle.BOLD}   Spring Boot :${AnsiStyle.NORMAL} ${spring-boot.formatted-version}
${AnsiStyle.BOLD}   Java        :${AnsiStyle.NORMAL} ${java.version}
${AnsiStyle.BOLD}   Profile(s)  :${AnsiStyle.NORMAL} ${spring.profiles.active:default}

# application.properties — image banner settings
spring.banner.image.location=classpath:banner.png
spring.banner.image.width=76        # width in characters (default 76)
spring.banner.image.height=0        # height is derived from the width and the aspect ratio by default
spring.banner.image.margin=2        # left margin in characters (default 2)
spring.banner.image.invert=false    # true for dark terminal themes
spring.banner.image.bitdepth=4      # 4 or 8 (default 4)
spring.banner.image.pixelmode=text  # text or block

# Both a text banner and an image banner exist -> BOTH are printed (image first):
spring.banner.location=classpath:banner.txt
spring.banner.image.location=classpath:logo.png

# Best practices:
# - simple, high-contrast logos work best
# - keep the source image small (64x64 to 128x128 pixels)
# - use it in dev profiles only; use a short text banner in production

# ── Banner mode ──────────────────────────────────────────────────────
spring.main.banner-mode=console   # console (default) | log | off

# ── ANSI color support ────────────────────────────────────────────────
spring.output.ansi.enabled=detect # detect (default) | always | never

# ── Banner location and encoding ──────────────────────────────────────
spring.banner.location=classpath:banner.txt            # default
# spring.banner.location=classpath:banners/my-banner.txt
# spring.banner.location=file:./banner.txt              # from the filesystem
spring.banner.charset=UTF-8                             # default

# ── Profile-specific control ──────────────────────────────────────────
# application-dev.properties:
#   spring.main.banner-mode=console
#   spring.output.ansi.enabled=always
# application-prod.properties:
#   spring.main.banner-mode=log       # banner appears in the startup log
#   spring.output.ansi.enabled=never  # no escape codes in log files
# src/test/resources/application.properties:
#   spring.main.banner-mode=off

# ── Other ways to switch it off ───────────────────────────────────────
# java -jar app.jar --spring.main.banner-mode=off
# java -Dspring.main.banner-mode=off -jar app.jar
# export SPRING_MAIN_BANNER_MODE=off
#
# In code:
#   SpringApplication app = new SpringApplication(Application.class);
#   app.setBannerMode(Banner.Mode.OFF);
#   // or: new SpringApplicationBuilder(Application.class).bannerMode(Banner.Mode.OFF).run(args);
#
# In a test:
#   @SpringBootTest(properties = "spring.main.banner-mode=off")

public class ApplicationBanner implements Banner {

    @Override
    public void printBanner(Environment environment,
                            Class<?> sourceClass,
                            PrintStream out) {

        String appName = environment.getProperty("spring.application.name", "MyApp");
        String version = environment.getProperty("app.version", "unknown");
        String[] active = environment.getActiveProfiles();   // works for profiles set in code too
        String profiles = active.length > 0 ? String.join(", ", active) : "default";

        out.println();
        out.println("  ======================================");
        out.printf ("  %s%n", appName);
        out.println("  ======================================");
        out.printf ("  Version     : %s%n", version);
        out.printf ("  Profile(s)  : %s%n", profiles);
        out.printf ("  Java        : %s%n", System.getProperty("java.version"));
        out.printf ("  PID         : %d%n", ProcessHandle.current().pid());
        out.printf ("  Started at  : %s%n", LocalDateTime.now());
        out.println();
    }
}

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(Application.class);
        app.setBanner(new ApplicationBanner());   // FALLBACK: used only if no banner.txt / image exists
        app.run(args);
    }
}

// ── Make your Banner always win: print it yourself and turn the standard one off ──
//   app.setBannerMode(Banner.Mode.OFF);
//   new ApplicationBanner().printBanner(environment, Application.class, System.out);
//   (for example from an ApplicationEnvironmentPreparedEvent listener)

// ── Reuse banner.txt placeholders from code: ──────────────────────────
//   app.setBanner(new ResourceBanner(new ClassPathResource("my-banner.txt")));

# ── Option 1: manifest ───────────────────────────────────────────────
# Maven (with spring-boot-starter-parent this is already configured):
#   <plugin>
#     <groupId>org.apache.maven.plugins</groupId>
#     <artifactId>maven-jar-plugin</artifactId>
#     <configuration>
#       <archive><manifest>
#         <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
#       </manifest></archive>
#     </configuration>
#   </plugin>
#
# Gradle (build.gradle):
#   tasks.named('bootJar') {
#       manifest {
#           attributes 'Implementation-Title': project.name,
#                      'Implementation-Version': project.version
#       }
#   }
#
# Verify the manifest of the built jar:
#   unzip -p target/myapp.jar META-INF/MANIFEST.MF | grep Implementation

# ── Option 2: a property filled in at build time (Maven starter parent) ─
# application.properties:
app.version=@project.version@

# banner.txt:
#   Version : ${app.version}