Server Tomcat v7.0 Server at localhost failed to start.

找了几个小时没找到原因，其实就是少了一个符号的问题

严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/upload_down]]
    at java.util.concurrent.FutureTask.report(FutureTask.java:122)
    at java.util.concurrent.FutureTask.get(FutureTask.java:188)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1241)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:819)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1702)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1692)
    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)

原来的web.xml配置

<servlet>
    <servlet-name>ListFileServlet</servlet-name>
    <servlet-class>com.xiaobao.web.ListFileServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>ListFileServlet</servlet-name>
    <url-pattern>listFileServlet</url-pattern>
</servlet-mapping>

更改后的web.xml配置

<servlet>
    <servlet-name>ListFileServlet</servlet-name>
    <servlet-class>com.xiaobao.web.ListFileServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>ListFileServlet</servlet-name>
    <url-pattern>/listFileServlet</url-pattern>
</servlet-mapping>

url-pattern里面少了一个 /