使用Root-Logger WARN显示Spring-Boot Banner

4 回答

• 1

  在打印 Banner 时，Spring Boot使用类 org.springframework.boot.SpringApplication 的 Logger ，其级别为 INFO .

  简单的解决方案是为此特定类启用 INFO 级别：

  <logger name="org.springframework.boot.SpringApplication"
          level="INFO" additivity="false">
      <appender-ref ref="FILE"/>
  </logger>
  

  回复于 2024-04-23T18:32:16+08:00
• 0

  我有同样的问题，只需在 application.properties 中设置此属性：

  spring.main.banner-mode=LOG
  

  现在它打印到控制台和文件，具有日志级别INFO . 只要您将根日志级别和追加者设置为接受INFO，您就会看到它 .

  <root level="info">
      <appender-ref ref="RollingFile" />
      <appender-ref ref="Console" />
  </root>
  

  回复于 2024-04-23T18:32:16+08:00
• 0

  这就是我想出的 . 它包含了在常规实现中更换 Logger 的想法 .

  使用默认日志实现的问题是通过slf4j bridge调整commons-logging的方式 .

  这可能是最活跃的代码之一，所以希望我们会在即将发布的spring-boot发行版中看到修复...

  第1步：注册新的应用程序监听器

  /META-INF/spring.factory

  org.springframework.context.ApplicationListener=ac.me.appevents.BannerDisplay
  

  第2步：实现应用程序侦听器

  package ac.me.appevents;
  
  import org.jetbrains.annotations.NotNull;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.slf4j.Marker;
  import org.slf4j.MarkerFactory;
  import org.springframework.boot.ResourceBanner;
  import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
  import org.springframework.context.ApplicationListener;
  import org.springframework.core.env.Environment;
  import org.springframework.core.io.DefaultResourceLoader;
  import org.springframework.core.io.Resource;
  import org.springframework.core.io.ResourceLoader;
  import org.springframework.util.ClassUtils;
  
  import java.io.ByteArrayOutputStream;
  import java.io.PrintStream;
  import java.io.UnsupportedEncodingException;
  
  public class BannerDisplay implements ApplicationListener<ApplicationEnvironmentPreparedEvent> {
      /**
       * Banner location property key.
       */
      private static final String BANNER_LOCATION_PROPERTY = "banner.location";
  
      /**
       * Default banner location.
       */
      private static final String BANNER_LOCATION_PROPERTY_VALUE = "banner.txt";
  
      private static final Logger LOG = LoggerFactory.getLogger(BannerDisplay.class);
  
      private static final Marker MRK = MarkerFactory.getMarker("Banner");
  
      private ResourceLoader resourceLoader;
  
      private Class<?> deduceMainApplicationClass() {
          try {
              StackTraceElement[] stackTrace = new RuntimeException().getStackTrace();
              for (StackTraceElement stackTraceElement : stackTrace) {
                  if ("main".equals(stackTraceElement.getMethodName())) {
                      return Class.forName(stackTraceElement.getClassName());
                  }
              }
          }
          catch (ClassNotFoundException ex) {
              // Swallow and continue
          }
          return null;
      }
  
      @Override
      public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
          Environment environment = event.getEnvironment();
  
          String location = environment.getProperty(BANNER_LOCATION_PROPERTY, BANNER_LOCATION_PROPERTY_VALUE);
          ResourceLoader resLoader = getResourceLoader();
          Resource resource = resLoader.getResource(location);
          if (resource.exists()) {
              ResourceBanner banner = new ResourceBanner(resource);
              ByteArrayOutputStream baos = new ByteArrayOutputStream();
              banner.printBanner(environment, deduceMainApplicationClass(), new PrintStream(baos));
              String charset = environment.getProperty("banner.charset", "UTF-8");
              try {
  
                  LOG.info(MRK, baos.toString(charset));
              }
              catch (UnsupportedEncodingException e) {
                  LOG.warn(MRK, "Unsupported banner charset encoding.", e);
              }
  
          }
      }
  
      @NotNull
      private ResourceLoader getResourceLoader() {
          if (resourceLoader == null) {
              this.resourceLoader = new DefaultResourceLoader(ClassUtils.getDefaultClassLoader());
          }
          return resourceLoader;
      }
  
      public void setResourceLoader(final ResourceLoader resourceLoader) {
          this.resourceLoader = resourceLoader;
      }
  }
  

  回复于 2024-04-23T18:32:16+08:00
• 6

  首先，我必须承认我没有对此进行测试，但至少它可能会给你一些想法 .

  您可以删除 spring.main.banner-mode=log 并提供您自己的包装器实现，该实现将使用 Logger 而不是提供的输出流 . 代码应如下所示：

  public class BannerLoggerWrapper implements Banner {
  
      private static final Log logger = LogFactory.getLog(BannerLoggerWrapper.class);
      private Banner actual;
  
      public BannerLoggerWrapper(Banner actual) {
          this.actual = actual;
      }
  
      @Override
      public void printBanner(Environment environment, Class<?> sourceClass, PrintStream out) {
          try {
              logger.info(createStringFromBanner(environment, sourceClass));
          } catch (UnsupportedEncodingException ex) {
              logger.warn("Failed to create String for banner", ex);
          }
      }
  
      private String createStringFromBanner(Environment environment, Class<?> sourceClass) throws UnsupportedEncodingException {
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          actual.printBanner(environment, sourceClass, new PrintStream(baos));
          String charset = environment.getProperty("banner.charset", "UTF-8");
          return baos.toString(charset);
      }
  
  }
  

  您可以在此类中将 logger.info 替换为 logger.warn ，或者您可以为此 Logger 创建特定的其他配置：

  <logger name="your.package.name.BannerLoggerWrapper" level="INFO" additivity="false">
      <appender-ref ref="FILE"/>
  </logger>
  

  根据documentation，您可以使用 SpringApplication.setBanner(…) 配置Spring Boot以使用Banner实现 .

  回复于 2024-04-23T18:32:16+08:00