JSP的jar类错误；The superclass "javax.servlet.http.HttpServlet" was not found on......报错

一、eclispe的jsp 首行报错错误原因为缺乏运行环境（推荐方法1）

The superclass "javax.servlet.http.HttpServlet" was not found on the Java Button..................

或者
Multiple annotations found at this line:

            - The superclass "javax.servlet.http.HttpServlet" was not found on the Java

             Build Path

            - The superclass "javax.servlet.http.HttpServlet" was not found on the Java

             Build Path

            - The superclass "javax.servlet.http.HttpServlet" was not found on the Java
             Build Path

1，bulid pase 里面缺乏导入RunTime：导入Library  ->server runtime,并在Order and Export中选择tomcat（需要eclipse配置tomcat）。
2，在WEB-INF目录-->新建lib-->选择tomcat安装目录里面的lib里面jar包，全部复制--->复制到lib里面