eclipse Server Tomcat Server at localhost failed to start.命令行可启动

eclipse中部署项目报错：

Server Tomcat  Server at localhost failed to start.

查看控制台报错信息如下,原来是web.xml文件有问题,导致不能启动

查看控制台报错信息

Caused by: java.lang.IllegalArgumentException: Invalid <url-pattern> MailSend in servlet mapping
    at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3432)
    at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3407)
    at org.apache.catalina.deploy.WebXml.configureContext(WebXml.java:1438)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1359)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:888)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:388)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5519)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)

检查了下 MailSend in servlet mapping

    <servlet>
    <servlet-name>MailSend</servlet-name>
    <servlet-class>com.csy.servlet.MailSend</servlet-class>
    </servlet>
    <servlet-mapping>
    <servlet-name>MailSend</servlet-name>
    <url-pattern>MailSend</url-pattern>
    </servlet-mapping>

发现<url-pattern>MailSend</url-pattern>少写了个/
正确的是

<url-pattern>/MailSend</url-pattern>