问题：
SpringBoot项目中集成了阿里开源Druid数据源，本地开发环境直接启动SpringBoot应用(SpringApplication.run方法)，启动成功，由于正式应用是部署在服务器已有的Tomcat环境中，经过改造将SpringBoot项目打成ROOT.war包后，部署到服务器上，启动应用程序时，报错了，错误信息如下所示：
15:13:34.616 repair [localhost-startStop-1] DEBUG o.springframework.jndi.JndiTemplate - Looking up JNDI object with name [java:comp/env/logging.level]
15:13:34.607 repair [localhost-startStop-1] DEBUG o.s.jndi.JndiPropertySource - JNDI lookup for name [logging.group] threw NamingException with message: Name [logging.group] is not bound in this Context. Unable to find [logging.group].. Returning null.
15:13:34.606 repair [localhost-startStop-1] DEBUG o.springframework.jndi.JndiTemplate - Looking up JNDI object with name [logging.group]
15:13:34.606 repair [localhost-startStop-1] DEBUG o.s.jndi.JndiLocatorDelegate - Converted JNDI name [java:comp/env/logging.group] not found - trying original name [logging.group]. javax.naming.NameNotFoundException: Name [logging.group] is not bound in this Context. Unable to find [logging.group].
15:13:34.580 repair [background-preinit] DEBUG o.h.v.m.ResourceBundleMessageInterpolator - Loaded expression factory via original TCCL
15:13:34.599 repair [localhost-startStop-1] DEBUG o.springframework.jndi.JndiTemplate - Looking up JNDI object with name [java:comp/env/logging.group]
15:13:34.578 repair [localhost-startStop-1] DEBUG o.s.jndi.JndiPropertySource - JNDI lookup for name [logging.group] threw NamingException with message: Name [logging.group] is not bound in this Context. Unable to find [logging.group].. Returning null.
15:13:34.577 repair [localhost-startStop-1] DEBUG o.springframework.jndi.JndiTemplate - Looking up JNDI object with name [logging.group]
15:13:34.577 repair [localhost-startStop-1] DEBUG o.s.jndi.JndiLocatorDelegate - Converted JNDI name [java:comp/env/logging.group] not found - trying original name [logging.group]. javax.naming.NameNotFoundException: Name [logging.group] is not bound in this Context. Unable to find [logging.group].
15:13:34.548 repair [localhost-startStop-1] DEBUG o.springframework.jndi.JndiTemplate - Looking up JNDI object with name [java:comp/env/logging.group]
... 74 common frames omitted
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:136)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:307)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:363)
at java.lang.reflect.Method.invoke(Method.java:497)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at cn.demo.repair.service.impl.VpServiceImpl.init(VpServiceImpl.java:42)
at java.util.Properties.load(Properties.java:341)
at java.util.Properties.load0(Properties.java:353)
at java.util.Properties$LineReader.readLine(Properties.java:434)
Caused by: java.lang.NullPointerException: null
... 61 common frames omitted
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1166)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1239)
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:273)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$120/684584821.getObject(Unknown Source)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:576)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1737)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:419)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:139)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'VpServiceImpl': Invocation of init method failed; nested exception is java.lang.NullPointerException
... 47 common frames omitted
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1166)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1239)
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:273)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$120/684584821.getObject(Unknown Source)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:575)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1378)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'approvalServiceImpl': Unsatisfied dependency expressed through field 'vpService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'VpServiceImpl': Invocation of init method failed; nested exception is java.lang.NullPointerException
... 33 common frames omitted
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1166)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1239)
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:273)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$120/684584821.getObject(Unknown Source)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:575)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1378)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'repairServiceImpl': Unsatisfied dependency expressed through field 'approvalService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'approvalServiceImpl': Unsatisfied dependency expressed through field 'vpService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'VpServiceImpl': Invocation of init method failed; nested exception is java.lang.NullPointerException
at java.lang.Thread.run(Thread.java:745)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1823)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:952)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:700)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:724)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5178)
at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:171)
at org.springframework.boot.web.servlet.support.SpringBootServletInitializer.onStartup(SpringBootServletInitializer.java:91)
at org.springframework.boot.web.servlet.support.SpringBootServletInitializer.createRootApplicationContext(SpringBootServletInitializer.java:137)
at org.springframework.boot.web.servlet.support.SpringBootServletInitializer.run(SpringBootServletInitializer.java:157)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:316)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$120/684584821.getObject(Unknown Source)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:575)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1378)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596)
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'repairController': Unsatisfied dependency expressed through field 'repairService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'repairServiceImpl': Unsatisfied dependency expressed through field 'approvalService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'approvalServiceImpl': Unsatisfied dependency expressed through field 'vpService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'VpServiceImpl': Invocation of init method failed; nested exception is java.lang.NullPointerException
15:07:53.610 repair [localhost-startStop-1] ERROR o.s.boot.SpringApplication - Application run failed
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
15:07:53.586 repair [localhost-startStop-1] INFO o.s.b.a.l.ConditionEvaluationReportLoggingListener -
15:07:53.536 repair [localhost-startStop-1] INFO c.alibaba.druid.pool.DruidDataSource - {dataSource-1} closed
15:07:53.258 repair [localhost-startStop-1] WARN o.s.b.w.s.c.AnnotationConfigServletWebServerApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'repairController': Unsatisfied dependency expressed through field 'repairService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'repairServiceImpl': Unsatisfied dependency expressed through field 'approvalService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'approvalServiceImpl': Unsatisfied dependency expressed through field 'vpService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'VpServiceImpl': Invocation of init method failed; nested exception is java.lang.NullPointerException
15:07:37.645 repair [localhost-startStop-1] INFO c.alibaba.druid.pool.DruidDataSource - {dataSource-1} inited
15:07:28.073 repair [localhost-startStop-1] INFO c.a.d.s.b.a.DruidDataSourceAutoConfigure - Init DruidDataSource
15:07:25.620 repair [localhost-startStop-1] INFO o.s.b.w.s.FilterRegistrationBean - Mapping filter: 'webStatFilter' to urls: [/*]
15:07:25.619 repair [localhost-startStop-1] INFO o.s.b.w.s.FilterRegistrationBean - Mapping filter: 'requestContextFilter' to: [/*]
15:07:25.619 repair [localhost-startStop-1] INFO o.s.b.w.s.FilterRegistrationBean - Mapping filter: 'formContentFilter' to: [/*]
15:07:25.618 repair [localhost-startStop-1] INFO o.s.b.w.s.FilterRegistrationBean - Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
15:07:25.618 repair [localhost-startStop-1] INFO o.s.b.w.s.FilterRegistrationBean - Mapping filter: 'errorPageFilter' to: [/*]
15:07:25.617 repair [localhost-startStop-1] INFO o.s.b.w.s.FilterRegistrationBean - Mapping filter: 'characterEncodingFilter' to: [/*]
15:07:25.570 repair [localhost-startStop-1] INFO o.s.b.w.s.ServletRegistrationBean - Servlet statViewServlet mapped to [/druid/*]
15:07:25.568 repair [localhost-startStop-1] INFO o.s.b.w.s.ServletRegistrationBean - Servlet dispatcherServlet mapped to [/]
15:07:23.151 repair [localhost-startStop-1] INFO o.s.web.context.ContextLoader - Root WebApplicationContext: initialization completed in 16648 ms
15:07:22.043 repair [localhost-startStop-1] INFO o.s.c.s.PostProcessorRegistrationDelegate$BeanPostProcessorChecker - Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$e7ee3861] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
15:07:17.690 repair [localhost-startStop-1] INFO o.s.d.r.c.RepositoryConfigurationDelegate - Finished Spring Data repository scanning in 421ms. Found 0 repository interfaces.
15:07:17.185 repair [localhost-startStop-1] INFO o.s.d.r.c.RepositoryConfigurationDelegate - Bootstrapping Spring Data repositories in DEFAULT mode.
15:07:17.154 repair [localhost-startStop-1] INFO o.s.d.r.c.RepositoryConfigurationDelegate - Multiple Spring Data modules found, entering strict repository configuration mode!
15:07:06.257 repair [localhost-startStop-1] INFO cn.demo.repair.RepairApplication - The following profiles are active: dev
15:07:06.256 repair [localhost-startStop-1] DEBUG cn.demo.repair.RepairApplication - Running with Spring Boot v2.1.0.RELEASE, Spring v5.1.2.RELEASE
15:07:06.235 repair [localhost-startStop-1] INFO cn.demo.repair.RepairApplication - Starting RepairApplication v0.0.1-SNAPSHOT on 10.40.20.119 with PID 102172 (/home/work/data/www/demo-repair/ROOT/WEB-INF/classes started by work in /home/work)
:: Spring Boot :: (v2.1.0.RELEASE)
=========|_|==============|___/=/_/_/_/
' |____| .__|_| |_|_| |_\__, | / / / /
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
. ____ _ __ _ _
复制代码分析：
分析报错信息，看到DruidDataSource初始化后，出现WARN信息，依赖生成bin的时候（最终生成VpServiceImpl的bin时）出现了空指针异常，如下异常信息：
15:07:53.536 repair [localhost-startStop-1] INFO c.alibaba.druid.pool.DruidDataSource - {dataSource-1} closed
15:07:53.258 repair [localhost-startStop-1] WARN o.s.b.w.s.c.AnnotationConfigServletWebServerApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'repairController': Unsatisfied dependency expressed through field 'repairService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'repairServiceImpl': Unsatisfied dependency expressed through field 'approvalService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'approvalServiceImpl': Unsatisfied dependency expressed through field 'vpService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'VpServiceImpl': Invocation of init method failed; nested exception is java.lang.NullPointerException
15:07:37.645 repair [localhost-startStop-1] INFO c.alibaba.druid.pool.DruidDataSource - {dataSource-1} inited
复制代码刚开始以为是SpringBoot集成DruidDataSource出了问题，各种查各种找，没有解决。
在网上搜能引起SpringBoot启动出现以下报错的原因，然也没有解决。
15:07:53.610 repair [localhost-startStop-1] ERROR o.s.boot.SpringApplication - Application run failed Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
异常意思是：应用程序运行启动ApplicationContext失败，要显示条件报告，请在“debug”模式下重新运行应用程序。
复制代码此时觉得可能是出发的方向错了，所以再次回过头来，仔细分析异常堆栈信息，看到两行：
at cn.demo.repair.service.impl.VpServiceImpl.init(VpServiceImpl.java:42)
at java.util.Properties.load(Properties.java:341)
复制代码觉得应该是自己程序中：在VpServiceImpl类初始化方法init中，Properties对象load文件时抛出了空指针异常。有了明确方向，开始研究出现问题的代码。
较详细的异常信息摘录：
15:13:34.548 repair [localhost-startStop-1] DEBUG o.springframework.jndi.JndiTemplate - Looking up JNDI object with name [java:comp/env/logging.group]
... 74 common frames omitted
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:136)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:307)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:363)
at java.lang.reflect.Method.invoke(Method.java:497)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at cn.demo.repair.service.impl.VpServiceImpl.init(VpServiceImpl.java:42)
at java.util.Properties.load(Properties.java:341)
at java.util.Properties.load0(Properties.java:353)
at java.util.Properties$LineReader.readLine(Properties.java:434)
Caused by: java.lang.NullPointerException: null
... 61 common frames omitted
复制代码结果发现直接用SpringBoot自带的SpringApplication.run方法启动应用程序，VpServiceImpl类的init方法不报错，而且应用程序启动成功，跑业务也正常，但是改造打成ROOT.war包后，部署到服务器的Tomcat上，就报错了，应用程序也启动失败。
哎呀，脑仁疼，怎么办，怎么办，怎么办......
脑子里一闪现，可能是打ROOT.war包出的问题，不对，不能再跑偏(因为之前版本部署ROOT.war没问题)，立即弄死这个想法。
正确的招：分析代码，添加详细的日志打印。
然后问题的根源逐渐浮出水面，直接看代码：
@Service
@Slf4j
public class VpServiceImpl implements VpService{
@Value("${vp.path}")
private String vpPath;
/**
* VP列表
*/
private Set vpSet;
/**
* Properties文件
*/
private Properties vpProperties;
/**
* 初始化VP列表
*/
@PostConstruct
private void init() {
vpProperties = new Properties();
try {
vpProperties.load(ClassLoader.getSystemResourceAsStream(vpPath));
} catch (IOException e) {
log.error("Failed to load the vp.properties file. vpPath = " + vpPath + ", IOException : " + e);
}
vpSet = vpProperties.stringPropertyNames();
}
@Override
public Set getVpSet() {
return vpSet;
}
@Override
public String getVpLeader(String username) {
if (!vpSet.contains(username)) {
return null;
}
String vpLeader = vpProperties.getProperty(username);
return StringUtils.isEmpty(vpLeader) ? vpProperties.getProperty("vpLeader", "xxx") : vpLeader;
}
@Override
public void setVpSet(Set vpSet) {
this.vpSet = vpSet;
}
@Override
public boolean addVp(String... vp) {
if (vpSet == null) {
vpSet = new HashSet<>();
}
return vpSet.addAll(Arrays.asList(vp));
}
@Override
public boolean addVp(List vpList) {
if (vpSet == null) {
vpSet = new HashSet<>();
}
return vpSet.addAll(vpList);
}
}
复制代码 vp.path在application.yml文件中的配置如下：
vp:
path: vp.properties
复制代码vp.properties在SpringBoot工程的resources目录下：
代码中Properties对象vpProperties转载InputStream输入流，而InputStream输入流是通过获取vp.properties文件资源转换而来的，这里是有问题的，ClassLoader.getSystemResourceAsStream(vpPath)在实际线上服务器环境中找不到vp.properties文件，所以报了空指针异常，导致线上应用程序启动失败。
解决方法：
代码修改：
@PostConstruct
private void init() {
vpProperties = new Properties();
try {
vpProperties.load(VpServiceImpl.class.getClassLoader().getResourceAsStream(vpPath));
} catch (Exception e) {
log.error("Failed to load the vp.properties file. vpPath = " + vpPath + ", Exception : " + e);
}
vpSet = vpProperties.stringPropertyNames();
}
复制代码修改点：
- 将
vpProperties.load(ClassLoader.getSystemResourceAsStream(vpPath));改为vpProperties.load(VpServiceImpl.class.getClassLoader().getResourceAsStream(vpPath)); - catch所有异常，不会导致应用程序启动失败。
总结：
程序报错了，不要瞎考虑，乱认为，一定要仔细研究异常栈信息，仔细研究异常栈信息，仔细研究异常栈信息（重要的事说三遍）。
知识扩展：
写累了，随后再扩展吧。