SpringBoot之自定义Banner详解

https://www.bootschool.net/ascii
http://www.network-science.de/ascii/
http://patorjk.com/software/taag/
http://www.degraeve.com/img2txt.php

public static void main(String[] args) {
		SpringApplication springApplication = new SpringApplication(Application.class);
		//开启Banner打印方式(OFF：关闭，CONSOLE：控制台输出，LOG：日志输出)
		springApplication.setBannerMode(Mode.LOG);
		springApplication.run(args);
	}

private Banner printBanner(ConfigurableEnvironment environment) {
       //是否开启Banner模式
        if (this.bannerMode == Mode.OFF) {
            return null;
        } else {
            ResourceLoader resourceLoader = this.resourceLoader != null ? this.resourceLoader : new DefaultResourceLoader((ClassLoader)null);
            SpringApplicationBannerPrinter bannerPrinter = new SpringApplicationBannerPrinter((ResourceLoader)resourceLoader, this.banner);
            return this.bannerMode == Mode.LOG ? bannerPrinter.print(environment, this.mainApplicationClass, logger) : bannerPrinter.print(environment, this.mainApplicationClass, System.out);
        }
    }

Banner print(Environment environment, Class<?> sourceClass, Log logger) {
	   //调用getBanner()方法
        Banner banner = this.getBanner(environment);
        try {
            logger.info(this.createStringFromBanner(banner, environment, sourceClass));
        } catch (UnsupportedEncodingException var6) {
            logger.warn("Failed to create String for banner", var6);
        }
        return new SpringApplicationBannerPrinter.PrintedBanner(banner, sourceClass);
    }

private Banner getBanner(Environment environment) {
    SpringApplicationBannerPrinter.Banners banners = new SpringApplicationBannerPrinter.Banners();
    //先获取image类型的banner
    banners.addIfNotNull(this.getImageBanner(environment));
    //在获取text类型的banner
    banners.addIfNotNull(this.getTextBanner(environment));
    if (banners.hasAtLeastOneBanner()) {
        // 如果至少有一个，则返回
        // Banners 也实现了 Banner 接口，运用了组合模式，实际上可同时打印图片和文本 banner。
        return banners;
    } else {
         // 返回自定义的banner(this.fallbackBanner) 或者 springboot默认的banner(DEFAULT_BANNER)
         // 默认的banner类：SpringBootBanner。
         // 自定义的banner：需要我们仿照SpringBootBanner去自定义一个类
         
         //this.fallbackBanner: 表示自定义的banner，此参数可在springboot启动类的main方法中设置,后续会介绍
         
         //   public static void main(String[] args) {
         //        SpringApplication springApplication = new SpringApplication(Application.class);
         //        springApplication.setBanner(new MyBanner());//自定义的banner
         //        springApplication.run(args);
         //   }
        
          return this.fallbackBanner != null ? this.fallbackBanner : DEFAULT_BANNER;
    }
}

//获取Text类型的banner
private Banner getTextBanner(Environment environment) {
    //先从spring.banner.location路径中去取，如果没有，默认banner.txt
    String location = environment.getProperty("spring.banner.location", "banner.txt");
    Resource resource = this.resourceLoader.getResource(location);
    try {
        if (resource.exists() && !resource.getURL().toExternalForm().contains("liquibase-core")) {
            return new ResourceBanner(resource);
        }
    } catch (IOException var5) {}
    return null;
}

//获取image类型的banner
private Banner getImageBanner(Environment environment) {
    String location = environment.getProperty("spring.banner.image.location");
    if (StringUtils.hasLength(location)) {
        Resource resource = this.resourceLoader.getResource(location);
        return resource.exists() ? new ImageBanner(resource) : null;
    } else {
        String[] var3 = IMAGE_EXTENSION;
        int var4 = var3.length;
        for(int var5 = 0; var5 < var4; ++var5) {
            String ext = var3[var5];
            Resource resource = this.resourceLoader.getResource("banner." + ext);
            if (resource.exists()) {
                return new ImageBanner(resource);
            }
        }
        return null;
    }
}

spring.banner.location=classpath:banner1.png
spring.banner.image.margin=2
spring.banner.image.height=76
spring.banner.charset=UTF-8
spring.banner.image.invert=false
spring.banner.image.location=banner1.png
spring.main.banner-mode=console
spring.main.show-banner=true

import org.springframework.boot.Banner;
import org.springframework.boot.ansi.AnsiColor;
import org.springframework.boot.ansi.AnsiOutput;
import org.springframework.boot.ansi.AnsiStyle;
import org.springframework.core.env.Environment;
import java.io.PrintStream;

public class MyBanner implements Banner {

    private static final String[] BANNER = new String[]{"", "  .   ____          _            __ _ _", " /\\\\ / ___'_ __ _ _(_)_ __  __ _ \\ \\ \\ \\", "( ( )\\___ | '_ | '_| | '_ \\/ _` | \\ \\ \\ \\", " \\\\/  ___)| |_)| | | | | || (_| |  ) ) ) )", "  '  |____| .__|_| |_|_| |_\\__, | / / / /", " =========|_|==============|___/=/_/_/_/"};

    public MyBanner() {
    }

    @Override
    public void printBanner(Environment environment, Class<?> sourceClass, PrintStream out) {
        String[] bannerArray = BANNER;
        int bannerLength = bannerArray.length;
        for(int i = 0; i < bannerLength; ++i) {
            String line = bannerArray[i];
            out.println(line);
        }
        out.println(AnsiOutput.toString(new Object[]{AnsiColor.GREEN, " :: Spring Boot :: ", AnsiColor.DEFAULT,  AnsiStyle.FAINT}));
        out.println();
    }
}

@SpringBootApplication
public class Application extends SpringBootServletInitializer {
   public static void main(String[] args) {
      SpringApplication springApplication = new SpringApplication(Application.class);
      //添加自定义banner
      springApplication.setBanner(new MyBanner());
      springApplication.run(args);
   }
}

AnsiColor： 用来设定字符的前景色
AnsiBackground： 用来设定字符的背景色
AnsiStyle： 用来控制加粗、斜体、下划线等等。

${application.version}   与 MANIFEST.MF文件中相同的版本号，比如1.5.4.RELEASE
${application.formatted-version}   格式化过的版本号就是加个v然后用括号包起来，比如(v1.5.4.RELEASE)
${application.title} 
${spring-boot.version} Spring Boot的版本
${spring-boot.formatted-version} 格式化过的版本