1、The superclass “javax.servlet.http.httpservlet” is not found in the build path

　　原因：未添加server library

　　解决：在工程的build path-》library中添加server runtime library

2. jsp错误： requires that an attribute name is preceded by whitespace

　引入的包格式出现问题

3. tomcat版本问题-Tomcat version 6.0 only supports J2EE 1.2, 1.3, 1.4, and Java EE 5 Web modules 

　　在eclipse的workspace里面找到该项目->.settings 文件夹->org.eclipse.wst.common.project.facet.core.xml
　　更改servlet版本