java 编译异常及其解决办法（持续更新）
1.解决办法：将jar版本降低适配 低版本的jdk或tomcat
1 严重: ContainerBase.addChild: start: 2 org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/EasyGo]] 3 at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) 4 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:754) 5 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:730) 6 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734) 7 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1140) 8 at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875) 9 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) 10 at java.util.concurrent.FutureTask.run(FutureTask.java:262) 11 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 12 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 13 at java.lang.Thread.run(Thread.java:745) 14 Caused by: java.lang.UnsupportedClassVersionError: org/springframework/web/SpringServletContainerInitializer : Unsupported major.minor version 52.0 (unable to load class [org.springframework.web.SpringServletContainerInitializer]) 15 at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2341) 16 at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:828) 17 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1277) 18 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1136) 19 at java.lang.Class.forName0(Native Method) 20 at java.lang.Class.forName(Class.java:278) 21 at org.apache.catalina.startup.WebappServiceLoader.loadServices(WebappServiceLoader.java:188) 22 at org.apache.catalina.startup.WebappServiceLoader.load(WebappServiceLoader.java:159) 23 at org.apache.catalina.startup.ContextConfig.processServletContainerInitializers(ContextConfig.java:1612) 24 at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1125) 25 at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:765) 26 at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299) 27 at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94) 28 at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5154) 29 at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) 30 ... 10 more 31 十二月 26, 2018 10:34:42 上午 org.apache.catalina.startup.HostConfig deployDirectory 32 严重: Error deploying web application directory [D:softwaremyeclipseapache-tomcat-8.5.31webappsEasyGo] 33 java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/EasyGo]] 34 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:758) 35 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:730) 36 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734) 37 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1140) 38 at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875) 39 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) 40 at java.util.concurrent.FutureTask.run(FutureTask.java:262) 41 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 42 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 43 at java.lang.Thread.run(Thread.java:745)
2.解决办法：点击该项目->properties->Deployment Assmebly->Add->Java Build Path Entries（手动将项目所需要的jar添加）
问题：使用tomcat运行Dynamic Web Project时，在webapps中的项目没有加载jar包
3.空指针:java NullPointerException 可能是包未导入。
4.解决方法：添加jar包javassist
问题：java.lang.ClassNotFoundException: javassist.ClassPath
5.解决方法：正常情况下springmvc的xml文件应放在WEB-INF下，命名规则为 [name]-servlet.xml “-servlet”这个字段是必不可少的 [name]你可以随便命名 但是为了规范和方便阅读 最好是springmvc-servlet.xml(我这里是测试随便起的) 同时你的xml文件中两个servlet要和你的name相同 不然会报错的,对应此处的HelloWeb,所以需要使用HelloWeb-servlet.xml。
问题：找不到xml
org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from ServletContext resource [/WEB-INF/HelloWeb-servlet.xml]; nested exception is java.io.FileNotFoundException: Could not open ServletContext resource [/WEB-INF/HelloWeb-servlet.xml]
6.解决方法：把 https 改为 http
问题：
java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens
7.解决方法：将attach 类型改为class AttachBean{Map<String,Object> tinfo}
问题：使用Gson自动化将json转化为javaBean的时候，属性String attach无法正确解析。因为收到的attach不是String类型，而是一个嵌套json
"attach": {
"tinfo": {
"22": "0"
}
},
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected a string but was BEGIN_OBJECT at line 1 column 280 path $.attach