org.springframework.boot.SpringApplicationBannerPrinter Maven / Gradle / Ivy
/*
* Copyright 2012-2022 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.boot;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.io.UnsupportedEncodingException;
import org.apache.commons.logging.Log;
import org.springframework.aot.hint.RuntimeHints;
import org.springframework.aot.hint.RuntimeHintsRegistrar;
import org.springframework.core.env.Environment;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
/**
* Class used by {@link SpringApplication} to print the application banner.
*
* @author Phillip Webb
*/
class SpringApplicationBannerPrinter {
static final String BANNER_LOCATION_PROPERTY = "spring.banner.location";
static final String DEFAULT_BANNER_LOCATION = "banner.txt";
private static final Banner DEFAULT_BANNER = new SpringBootBanner();
private final ResourceLoader resourceLoader;
private final Banner fallbackBanner;
SpringApplicationBannerPrinter(ResourceLoader resourceLoader, Banner fallbackBanner) {
this.resourceLoader = resourceLoader;
this.fallbackBanner = fallbackBanner;
}
Banner print(Environment environment, Class sourceClass, Log logger) {
Banner banner = getBanner(environment);
try {
logger.info(createStringFromBanner(banner, environment, sourceClass));
}
catch (UnsupportedEncodingException ex) {
logger.warn("Failed to create String for banner", ex);
}
return new PrintedBanner(banner, sourceClass);
}
Banner print(Environment environment, Class sourceClass, PrintStream out) {
Banner banner = getBanner(environment);
banner.printBanner(environment, sourceClass, out);
return new PrintedBanner(banner, sourceClass);
}
private Banner getBanner(Environment environment) {
Banner textBanner = getTextBanner(environment);
if (textBanner != null) {
return textBanner;
}
if (this.fallbackBanner != null) {
return this.fallbackBanner;
}
return DEFAULT_BANNER;
}
private Banner getTextBanner(Environment environment) {
String location = environment.getProperty(BANNER_LOCATION_PROPERTY, DEFAULT_BANNER_LOCATION);
Resource resource = this.resourceLoader.getResource(location);
try {
if (resource.exists() && !resource.getURL().toExternalForm().contains("liquibase-core")) {
return new ResourceBanner(resource);
}
}
catch (IOException ex) {
// Ignore
}
return null;
}
private String createStringFromBanner(Banner banner, Environment environment, Class mainApplicationClass)
throws UnsupportedEncodingException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
banner.printBanner(environment, mainApplicationClass, new PrintStream(baos));
String charset = environment.getProperty("spring.banner.charset", "UTF-8");
return baos.toString(charset);
}
/**
* Decorator that allows a {@link Banner} to be printed again without needing to
* specify the source class.
*/
private static class PrintedBanner implements Banner {
private final Banner banner;
private final Class sourceClass;
PrintedBanner(Banner banner, Class sourceClass) {
this.banner = banner;
this.sourceClass = sourceClass;
}
@Override
public void printBanner(Environment environment, Class sourceClass, PrintStream out) {
sourceClass = (sourceClass != null) ? sourceClass : this.sourceClass;
this.banner.printBanner(environment, sourceClass, out);
}
}
static class SpringApplicationBannerPrinterRuntimeHints implements RuntimeHintsRegistrar {
@Override
public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
hints.resources().registerPattern("banner.txt");
}
}
}