問題詳細：
啟動項目時，報錯：
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.<clinit>(SearchIPAttributionService.java:28) ... 40 more
解決過程：
1、檢查配置，反反復復看了很多遍，確認沒有問題。
2、 網上找了很多資料，類似的問題很多，看過答案以后依舊不得其要領。只好繼續看報錯代碼，直到看到這一句：
Caused by: java.lang.NullPointerException at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:133) at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:66) at ***.***.SearchIPAttributionService.<clinit>(SearchIPAttributionService.java:28)
問題應該在本身的代碼上，但是，我記得代碼是測試過的，沒有問題。但是，沒有其他辦法，只能順着提示一步步尋找問題所在。最終，確實問題出在代碼上。Spring在實例化這個類的時候，先執行靜態方法，此時某個類還未實例化(檢查是否已加注解)，故而報了這個空指針錯誤。
經驗教訓：
1、解決問題，不要急躁，要淡定，淡定，淡定。
2、仔細看報錯信息。
3、每次修改過代碼以后，都要記得進行測試，確保修改是正確的。