SpringBoot banner內容獲取和打印原理

進入run方法。可以發現有一個printBanner方法

 

1、進入printBanner方法

	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);
	}

　　第一行判斷Banner的模式是否關閉，如果關閉直接返回。

 

2、進入bannerPrinter.print(environment, this.mainApplicationClass, System.out)

	public Banner print(Environment environment, Class<?> sourceClass, PrintStream out) {
		Banner banner = getBanner(environment);
		banner.printBanner(environment, sourceClass, out);
		return new PrintedBanner(banner, sourceClass);
	}

getBanner(environment);是獲取
printBanner是打印

還是比較簡單，可以查看源碼

 

3、圖片打印的關鍵代碼

ImageBanner中的printBanner方法。其中readFrames是java中圖案打印方法