今天部署应用到Tomcat，发现启动过程中有异常，验证码前台出不来，以为是此异常导致的，后来解决了Java.NET.UnknownHostException，登录页面的验证码还是出不来不知是何问题。
详细异常输出
报错方式：java.Net.UnknownHostException: 主机名: 主机名
java.net.UnknownHostException: RD-CD-APP122.wlyd.local: RD-CD-APP122.wlyd.local
at java.net.InetAddress.getLocalHost(InetAddress.java:1473)
at net.sf.ehcache.Cache.<clinit>(Cache.java:214)
at net.sf.ehcache.config.ConfigurationHelper.createCache(ConfigurationHelper.java:296)
at net.sf.ehcache.config.ConfigurationHelper.createDefaultCache(ConfigurationHelper.java:219)
at net.sf.ehcache.CacheManager.configure(CacheManager.java:722)
at net.sf.ehcache.CacheManager.doInit(CacheManager.java:439)
at net.sf.ehcache.CacheManager.init(CacheManager.java:377)
at net.sf.ehcache.CacheManager.<init>(CacheManager.java:259)
at net.sf.ehcache.CacheManager.newInstance(CacheManager.java:1037)
at net.sf.ehcache.CacheManager.newInstance(CacheManager.java:818)
at net.sf.ehcache.CacheManager.create(CacheManager.java:799)
at com.wlyd.fmcgwms.util.ehcache.EhcacheUtil.<clinit>(EhcacheUtil.java:18)
at com.wlyd.fmcgwms.util.sysinit.InitSysProperties.setApplicationContext(InitSysProperties.java:55)
at org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces (ApplicationContextAwareProcessor.java:117)
at org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization (ApplicationContextAwareProcessor.java:92)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization (AbstractAutowireCapableBeanFactory.java:396)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean (AbstractAutowireCapableBeanFactory.java:1505)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean (AbstractAutowireCapableBeanFactory.java:521)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean (AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject (AbstractBeanFactory.java:296)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton (DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean (AbstractBeanFactory.java:293)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean (AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons (DefaultListableBeanFactory.java:628)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization (AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh (AbstractApplicationContext.java:479)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext (ContextLoader.java:389)
at org.springframework.web.context.ContextLoader.initWebApplicationContext (ContextLoader.java:294)
at org.springframework.web.context.ContextLoaderListener.contextInitialized (ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart (StandardContext.java:4994)
at org.apache.catalina.core.StandardContext.startInternal (StandardContext.java:5492)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1081)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1877)
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:745)
Caused by: java.net.UnknownHostException: RD-CD-APP122.wlyd.local
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:901)
at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1293)
at java.net.InetAddress.getLocalHost(InetAddress.java:1469)
... 41 more
[localhost-startStop-1] INFO [org.quartz.core.SchedulerSignalerImpl] - Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
[localhost-startStop-1] INFO [org.quartz.core.QuartzScheduler] - Quartz Scheduler v.1.8.5 created.
[localhost-startStop-1] INFO [org.quartz.simpl.RAMJobStore] - RAMJobStore initialized.
[localhost-startStop-1] INFO [org.quartz.core.QuartzScheduler] - Scheduler meta-data: Quartz Scheduler (v1.8.5) 'SpringJobSchedulerFactoryBean' with instanceId 'NON_CLUSTERED'
Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
NOT STARTED.
Currently in standby mode.
Number of jobs executed: 0
Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.
解决方法
命令：vi /etc/hosts
在最后一行添加：127.0.0.1 主机名。我的系统改成了如下图所示：
修改完成，保存文件，之后就不会有此异常发生了。