异常：Handler dispatch failed; nested exception is java.lang.ExceptionInInitializerError...已解决
org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.ExceptionInInitializerError at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1054) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:96) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123) ~[druid-1.1.10.jar:1.1.10] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:88) ~[spring-boot-actuator-2.1.8.RELEASE.jar:2.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.cloud.sleuth.instrument.web.ExceptionLoggingFilter.doFilter(ExceptionLoggingFilter.java:50) [spring-cloud-sleuth-core-2.1.1.RELEASE.jar:2.1.1.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.24.jar:9.0.24] at brave.servlet.TracingFilter.doFilter(TracingFilter.java:86) [brave-instrumentation-servlet-5.6.1.jar:?] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:114) [spring-boot-actuator-2.1.8.RELEASE.jar:2.1.8.RELEASE] at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:104) [spring-boot-actuator-2.1.8.RELEASE.jar:2.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) [spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) [spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587) [tomcat-embed-core-9.0.24.jar:9.0.24] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.24.jar:9.0.24] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_191] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_191] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.24.jar:9.0.24] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_191] Caused by: java.lang.ExceptionInInitializerError at com.sgcc.epri.platform.controller.TreeController.getImageUrl(TreeController.java:107) ~[classes/:?] at com.sgcc.epri.platform.controller.TreeController$$FastClassBySpringCGLIB$$b19f1730.invoke(<generated>) ~[classes/:?] at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:56) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:55) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at com.sgcc.epri.platform.controller.TreeController$$EnhancerBySpringCGLIB$$35178ab0.getImageUrl(<generated>) ~[classes/:?] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_191] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_191] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_191] at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_191] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] ... 65 more Caused by: java.lang.NullPointerException at com.sgcc.epri.platform.util.HttpUtil.getUrl(HttpUtil.java:37) ~[classes/:?] at com.sgcc.epri.platform.util.OSSClientUtil.<clinit>(OSSClientUtil.java:60) ~[classes/:?] at com.sgcc.epri.platform.controller.TreeController.getImageUrl(TreeController.java:107) ~[classes/:?] at com.sgcc.epri.platform.controller.TreeController$$FastClassBySpringCGLIB$$b19f1730.invoke(<generated>) ~[classes/:?] at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:56) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:55) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE] at com.sgcc.epri.platform.controller.TreeController$$EnhancerBySpringCGLIB$$35178ab0.getImageUrl(<generated>) ~[classes/:?] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_191] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_191] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_191] at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_191] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE] ... 65 more
异常再现：
上面是我复制的控制台所有异常，下面是异常的主要内容：html
重点留意下面这行提示：java
异常缘由：
问题应该在自己的代码上，但是我记得代码是测试过的，保证逻辑没有问题，没可能出现“NullPointException”。可是，没有其余办法，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。web
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。spring
解决办法：
小编的问题出在：手写了一个Utils类，向外部提供static的静态方法，内部须要加载一些写在propertis文件中的常量。而JVM加载static方法老是在读取propertis文件以前进行，致使方法执行时候出现空指针异常。apache
方法1：将写在propertis文件中的常量写在Utils方法中tomcat
方法2：将JVM读取propertis文件中的过程放在加载static方法以前websocket
着急下班了，改天再把方法的具体实现补齐，若是你恰巧须要，庆私信我！mvc
少侠请留步 ... ヾ(◍°∇°◍)ﾉﾞ ...
欢迎点赞、评论、加关注，让更多人看到学到赚到
更多精彩，请关注个人"今日头条号"：Java云笔记app