是这样设置的么?
<Context className="org.apache.catalina.core.StandardContext" cachingAllowed="true" charsetMapperClass="org.apache.catalina.util.CharsetMapper" cookies="true" crossContext="true" debug="0" displayName="Tomcat Examples" docBase="d:/work/sm/defaultroot" mapperClass="org.apache.catalina.core.StandardContextMapper" path="/sm" privileged="false" reloadable="true" swallowOutput="false" useNaming="true" wrapperClass="org.apache.catalina.core.StandardWrapper">
</Context>