SpringBoot之自定義啟動異常堆棧信息打印方式

更新時間：2021年08月09日 08:38:52 作者：weixin_36276193

這篇文章主要介紹了SpringBoot之自定義啟動異常堆棧信息打印方式，具有很好的參考價值，希望對大家有所幫助。如有錯誤或未考慮完全的地方，望不吝賜教

在SpringBoot項目啟動過程中，當一些配置或者其他錯誤信息會有一些的規(guī)范的提示信息

***************************
APPLICATION FAILED TO START
***************************

Description:

Web server failed to start. Port 8080 was already in use.

Action:

Identify and stop the process that's listening on port 8080 or configure this application to listen on another port.

在SpringBoot 中其實現(xiàn)原理是什么，我們該如何自定義異常信息呢

1、SpringBoot異常處理的源碼分析

在springboot啟動的核心方法run中會加載所有的SpringBootExceptionReporter

 exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class,
     new Class[] { ConfigurableApplicationContext.class }, context);

調用了getSpringFactoriesInstances方法

private <T> Collection<T> getSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, Object... args) {
  ClassLoader classLoader = getClassLoader();
  // Use names and ensure unique to protect against duplicates
  Set<String> names = new LinkedHashSet<>(SpringFactoriesLoader.loadFactoryNames(type, classLoader));
  List<T> instances = createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names);
  AnnotationAwareOrderComparator.sort(instances);
  return instances;
 }

其主要通過Spring的Factories機制來加載

public ConfigurableApplicationContext run(String... args) {
  StopWatch stopWatch = new StopWatch();
  stopWatch.start();
  ConfigurableApplicationContext context = null;
  Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
  configureHeadlessProperty();
  SpringApplicationRunListeners listeners = getRunListeners(args);
  listeners.starting();
  try {
   ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
   ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments);
   configureIgnoreBeanInfo(environment);
   Banner printedBanner = printBanner(environment);
   context = createApplicationContext();
   exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class,
     new Class[] { ConfigurableApplicationContext.class }, context);
   prepareContext(context, environment, listeners, applicationArguments, printedBanner);
   refreshContext(context);
   afterRefresh(context, applicationArguments);
   stopWatch.stop();
   if (this.logStartupInfo) {
    new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);
   }
   listeners.started(context);
   callRunners(context, applicationArguments);
  }
  catch (Throwable ex) {
  //異常捕獲中，向用戶打印異常信息
   handleRunFailure(context, ex, exceptionReporters, listeners);
   throw new IllegalStateException(ex);
  }

  try {
   listeners.running(context);
  }
  catch (Throwable ex) {
   handleRunFailure(context, ex, exceptionReporters, null);
   throw new IllegalStateException(ex);
  }
  return context;
 }

在try catch中，catch會打印異常信息

private void handleRunFailure(ConfigurableApplicationContext context, Throwable exception,
   Collection<SpringBootExceptionReporter> exceptionReporters, SpringApplicationRunListeners listeners) {
  try {
   try {
    handleExitCode(context, exception);
    if (listeners != null) {
     listeners.failed(context, exception);
    }
   }
   finally {
    reportFailure(exceptionReporters, exception);
    if (context != null) {
     context.close();
    }
   }
  }
  catch (Exception ex) {
   logger.warn("Unable to close ApplicationContext", ex);
  }
  ReflectionUtils.rethrowRuntimeException(exception);
 }

 private void reportFailure(Collection<SpringBootExceptionReporter> exceptionReporters, Throwable failure) {
  try {
   for (SpringBootExceptionReporter reporter : exceptionReporters) {
    if (reporter.reportException(failure)) {
     registerLoggedException(failure);
     return;
    }
   }
  }
  catch (Throwable ex) {
   // Continue with normal handling of the original failure
  }
  if (logger.isErrorEnabled()) {
   logger.error("Application run failed", failure);
   registerLoggedException(failure);
  }
 }

遍歷exceptionReporters，打印日常信息

SpringBootExceptionReporter-

SpringBootExceptionReporter是一個回調接口，用于支持對SpringApplication啟動錯誤的自定義報告。里面就一個報告啟動失敗的方法。

其實現(xiàn)類：org.springframework.boot.diagnostics.FailureAnalyzers

用于觸發(fā)從spring.factories加載的FailureAnalyzer和FailureAnalysisReporter實例。

2、如何自定義異常信息

/**
 * <p>
 *
 * <p>
 *
 * @author: xuwd
 * @time: 2020/11/16 10:52
 */
public class WannaStopException extends RuntimeException {
}

自定義異常信息打印

public class StopFailureAnalyzer
        extends AbstractFailureAnalyzer<WannaStopException> {
    @Override
    protected FailureAnalysis analyze(Throwable rootFailure, WannaStopException cause) {
        for (StackTraceElement stackTraceElement : cause.getStackTrace()) {
            if (stackTraceElement.getClassName().equals("com.pigx.demo.Config21")) {
                return new FailureAnalysis("A想停止", "別要A了", cause);
            }
        }
        return null;
    }
}

接下來令他生效，通過上面分析可以可看出需要通過AutoConfigurationImportSelector，類似于自定義SpringBoot Starter AutoConfiguration的形式，我們需要在META-INF/spring.factories文件內進行定義，如下所示：