Springboot banner
Banner的实现类如下：
- SpringBootBanner：Banner的默认实现类
- ImageBanner：用来打印图片日志的banner
- ResourceBanner:资源Banner
Springboot在启动的时候，默认情况下会打印如下信息
. ____ _ __ _ _
/\ / ___'_ __ _ _(_)_ __ __ _
( ( )\___ | '_ | '_| | '_ / _` |
\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.2.5.RELEASE)
可以分析源码看看为什么打印如下日志
SpringApplication中run方法
public ConfigurableApplicationContext run(String... args) {
...
Banner printedBanner = printBanner(environment);
....
return context;
}
调用printBanner(ConfigurableEnvironment environment)的方法
private Banner printBanner(ConfigurableEnvironment environment) {
if (this.bannerMode == Banner.Mode.OFF) {
return null;
}
//获取资源加载
ResourceLoader resourceLoader = (this.resourceLoader != null) ? this.resourceLoader
: new DefaultResourceLoader(getClassLoader());
//创建SpringApplicationBannerPrinter对象
SpringApplicationBannerPrinter bannerPrinter = new SpringApplicationBannerPrinter(resourceLoader, this.banner);
if (this.bannerMode == Mode.LOG) {
return bannerPrinter.print(environment, this.mainApplicationClass, logger);
}
//打印日志
return bannerPrinter.print(environment, this.mainApplicationClass, System.out);
}
Banner print(Environment environment, Class<?> sourceClass, PrintStream out) {
//获取Banner
Banner banner = getBanner(environment);
//打印Banner
banner.printBanner(environment, sourceClass, out);
return new PrintedBanner(banner, sourceClass);
}
getBanner(Environment environment)方法
private Banner getBanner(Environment environment) {
Banners banners = new Banners();
//添加ImageBanner
banners.addIfNotNull(getImageBanner(environment));
//添加TextBanner
banners.addIfNotNull(getTextBanner(environment));
if (banners.hasAtLeastOneBanner()) {
return banners;
}
if (this.fallbackBanner != null) {
return this.fallbackBanner;
}
return DEFAULT_BANNER;
}
static final String BANNER_IMAGE_LOCATION_PROPERTY = "spring.banner.image.location";
static final String[] IMAGE_EXTENSION = { "gif", "jpg", "png" };
private Banner getImageBanner(Environment environment) {
String location = environment.getProperty(BANNER_IMAGE_LOCATION_PROPERTY);
if (StringUtils.hasLength(location)) {
Resource resource = this.resourceLoader.getResource(location);
return resource.exists() ? new ImageBanner(resource) : null;
}
//获取banner.gif，banner.jpg,banner.png
for (String ext : IMAGE_EXTENSION) {
Resource resource = this.resourceLoader.getResource("banner." + ext);
if (resource.exists()) {
return new ImageBanner(resource);
}
}
return null;
}
static final String BANNER_LOCATION_PROPERTY = "spring.banner.location";
static final String DEFAULT_BANNER_LOCATION = "banner.txt";
private Banner getTextBanner(Environment environment) {
//获取路径下的banner.txt;
String location = environment.getProperty(BANNER_LOCATION_PROPERTY, DEFAULT_BANNER_LOCATION);
Resource resource = this.resourceLoader.getResource(location);
if (resource.exists()) {
return new ResourceBanner(resource);
}
return null;
}
通过上面的代码可以知道，如果在classpath路径下面添加了banner.txt,banner.jpg文件后，首先加载banner.jpg，然后加载banner.txt文件，后面都会打印出来。
下面通实现自己的Banner
@SpringBootApplication
public class Application {
public static void main(String[] args) {
//SpringApplication.run(Application.class,args);
SpringApplication application=new SpringApplication(Application.class);
//关闭banner
// application.setBannerMode(Banner.Mode.OFF);
application.setBanner(new Mybanner());
application.run(args);
// SpringApplicationBuilder applicationBuilder=new SpringApplicationBuilder();
// //applicationBuilder.profiles("");
// applicationBuilder.bannerMode(Banner.Mode.OFF).run(args);
}
}
public class Mybanner implements Banner {
private static final String BANNER = "Spring Mybanner";
@Override
public void printBanner(Environment environment, Class<?> sourceClass, PrintStream out) {
System.out.println(BANNER);
}
}