org.apache.catalina.core.StandardWrapperValve invoke报错

tomcat报错如下：

HTTP Status 404 - Servlet xxx is not available

---

type Status report

message Servlet xxx is not available

description The requested resource is not available.

---

Apache Tomcat/6.0.37

org.apache.catalina.core.StandardWrapperValve invoke

INFO: Servlet xxx is currently unavailable

 

解决方案： 查看是否正确生成class文件 1.clean project 2.清空tomcat缓存 3.重新发布工程