Springboot项目报错解决方案

项目启动时报错Instantiation of bean failed; nested exception is java.lang.ExceptionInInitializerError

错误日志如下：

启动项目时，报错：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'searchIPAttributionService' defined in file [***\service\SearchIPAttributionService.class]: 
Instantiation of bean failed; nested exception is java.lang.ExceptionInInitializerError
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1013)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:959)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:490)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:626)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:651)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:599)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:665)
    at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:518)
    at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:459)
    at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
    at javax.servlet.GenericServlet.init(GenericServlet.java:158)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1284)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1197)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1087)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5266)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5554)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1263)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1948)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ExceptionInInitializerError
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1006)
    ... 33 more
Caused by: java.lang.NullPointerException
    at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:133)
    at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:66)
    at ***.***.SearchIPAttributionService.(SearchIPAttributionService.java:28)
    ... 40 more

在排除问题时，一直没有发现什么异常，后续通过堆栈错误，看到最后的错误信息

Caused by: java.lang.NullPointerException
    at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:133)
    at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:66)
    at ***.***.SearchIPAttributionService.(SearchIPAttributionService.java:28)

 问题应该在本身的代码上，但是，我记得代码是测试过的，没有问题。但是，没有其他办法，只能顺着提示一步步寻找问题所在。最终，确实问题出在代码上。Spring在实例化这个类的时候，先执行静态方法，此时某个类还未实例化(检查是否已加注解)，故而报了这个空指针错误。

经验教训：

1、解决问题，不要急躁，要淡定，淡定，淡定。

2、仔细看报错信息。

3、每次修改过代码以后，都要记得进行测试，确保修改是正确的。

4、迁移其他项目的Service服务时，看看调用的任务关系图