构建了一个springboot（springboot2.0版本）项目，在项目启动后报错，报错日志如下：
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:125)
at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108)
at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190)
at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132)
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'defaultValidator' defined in class path resource [org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.class]: Invocation of init method failed; nested exception is java.lang.NoSuchMethodError: javax.validation.BootstrapConfiguration.getClockProviderClassName()Ljava/lang/String;
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1745)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:576)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:316)
at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:127)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117)
... 24 more
Caused by: java.lang.NoSuchMethodError: javax.validation.BootstrapConfiguration.getClockProviderClassName()Ljava/lang/String;
at org.hibernate.validator.internal.xml.config.ValidationBootstrapParameters.<init>(ValidationBootstrapParameters.java:63)
at org.hibernate.validator.internal.engine.ConfigurationImpl.parseValidationXml(ConfigurationImpl.java:540)
at org.hibernate.validator.internal.engine.ConfigurationImpl.buildValidatorFactory(ConfigurationImpl.java:337)
at org.springframework.validation.beanvalidation.LocalValidatorFactoryBean.afterPropertiesSet(LocalValidatorFactoryBean.java:309)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1804)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1741)
... 39 more
从错误信息上看Caused by: java.lang.NoSuchMethodError: javax.validation.BootstrapConfiguration.getClockProviderClassName()Ljava/lang/String;导致错误的最终根源是这个方法执行失败了，找不到这个方法，这种情况一般要么是缺少jar包，要么是jar包冲突，有多个相同的jar包。
定位这个方法是org.hibernate.validator这个jar包的中调用ValidationBootstrapParameters（），查看maven结构可知
getClockProviderClassName（）查看源码知道在javaee-api中，而其最终的实现由jdk提供，已经能确定jdk是有的，那么为什么会还是这个不到这个方法呢，那么问题只可能出在api中，api没有这个方法
如果选择的是javaee-api的版本是7.0，是没有getClockProviderClassName()这个方法的，只需要把api版本改为8.0即可
有些人可能用7.0的api，启动springboot时却不会出错，问题在于你的springboot的版本，如果是springboot2.0以下的版本，如1.2版本，是不会出这个问题的，springboot2.0不支持jdk1.7，只支持1.8及其以上版本。