---

title: SpringBoot之Banner tags:

• SpringBoot
• banner categories: springboot date: 2017-11-14 22:48:02

---

背景

初次執行SpringBoot的小夥伴想必對於SpringBoot列印的Banner很感興趣

通常長成這樣

一個Spring撲面而來~

那麼我們能否定製自己的啟動頁呢？

原始碼

SpringBoot在啟動時會呼叫如下一段程式碼

    private Banner printBanner(ConfigurableEnvironment environment) {
       if (this.bannerMode == Banner.Mode.OFF) {
          return null;
       }
       ResourceLoader resourceLoader = this.resourceLoader != null ? this.resourceLoader
             : new DefaultResourceLoader(getClassLoader());
       SpringApplicationBannerPrinter bannerPrinter = new SpringApplicationBannerPrinter(
             resourceLoader, this.banner);
       if (this.bannerMode == Mode.LOG) {
          return bannerPrinter.print(environment, this.mainApplicationClass, logger);
       }
       return bannerPrinter.print(environment, this.mainApplicationClass, System.out);
    }
    public Banner print(Environment environment, Class<?> sourceClass, PrintStream out) {
       Banner banner = getBanner(environment, this.fallbackBanner);
       banner.printBanner(environment, sourceClass, out);
       return new PrintedBanner(banner, sourceClass);
    }
    private Banner getBanner(Environment environment, Banner definedBanner) {
       Banners banners = new Banners();
       banners.addIfNotNull(getImageBanner(environment));
       banners.addIfNotNull(getTextBanner(environment));
       if (banners.hasAtLeastOneBanner()) {
          return banners;
       }
       if (this.fallbackBanner != null) {
          return this.fallbackBanner;
       }
       return DEFAULT_BANNER;
    }
    private static final Banner DEFAULT_BANNER = new SpringBootBanner();
複製程式碼

而 SpringBootBanner長成這樣

    /**
     * Default Banner implementation which writes the 'Spring' banner.
     *
     * @author Phillip Webb
     */
    class SpringBootBanner implements Banner {
     
       private static final String[] BANNER = { "",
             "  .   ____          _            __ _ _",
             " /\\\\ / ___'_ __ _ _(_)_ __  __ _ \\ \\ \\ \\",
             "( ( )\\___ | '_ | '_| | '_ \\/ _` | \\ \\ \\ \\",
             " \\\\/  ___)| |_)| | | | | || (_| |  ) ) ) )",
             "  '  |____| .__|_| |_|_| |_\\__, | / / / /",
             " =========|_|==============|___/=/_/_/_/" };
     
       private static final String SPRING_BOOT = " :: Spring Boot :: ";
     
       private static final int STRAP_LINE_SIZE = 42;
     
       @Override
       public void printBanner(Environment environment, Class<?> sourceClass,
             PrintStream printStream) {
          for (String line : BANNER) {
             printStream.println(line);
          }
          String version = SpringBootVersion.getVersion();
          version = (version == null ? "" : " (v" + version + ")");
          String padding = "";
          while (padding.length() < STRAP_LINE_SIZE
                - (version.length() + SPRING_BOOT.length())) {
             padding += " ";
          }
     
          printStream.println(AnsiOutput.toString(AnsiColor.GREEN, SPRING_BOOT,
                AnsiColor.DEFAULT, padding, AnsiStyle.FAINT, version));
          printStream.println();
       }
     
    }
複製程式碼

上述程式碼可以看到banner存在兩種 imageBanner和textBanner

imageBanner需要配置屬性為banner.image.location

或者支援名為banner格式為 "gif", "jpg", "png的圖片

textBanner支援預設情況下在banner.location 或者預設為banner.txt

比如我們可以如下設定

在resource分別放置banner.txt和banner.png

banner.png

banner.txt

    /$$$$$$$$ /$$$$$$
    | $$_____//$$__  $$
    | $$     | $$  \__/
    | $$$$$  | $$$$$$$
    | $$__/  | $$__  $$
    | $$     | $$  \ $$
    | $$     |  $$$$$$/
    |__/      \______/
複製程式碼

我們可以看一下結果

哈哈 F6小人變成了這樣！！！

生成文字banner可以使用 patorjk.com/software/ta… 【同樣可以用在javascript 列印出console~】