筆者新建了一個QQ群：571278542 。歡迎大家加入！ tomcat重啟兩次的原因是appBase和Context中docBase設定的值導致的，只需要把appBase置為空，docBase寫專案的絕對路徑就可以了，程式碼如下：

      <Host name="localhost"  appBase=""
            unpackWARs="true" autoDeploy="true">
		<Context path="/" docBase="F:/Tomcat8.5/webroot/taocloud" debug="0"/>
        <!-- SingleSignOn valve, share authentication between web applications
             Documentation at: /docs/config/valve.html -->
        <!--
        <Valve className="org.apache.catalina.authenticator.SingleSignOn" />
        -->

        <!-- Access log processes all example.
             Documentation at: /docs/config/valve.html
             Note: The pattern used is equivalent to using pattern="common" -->
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

      </Host>