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

1、安装tomcat ，tomcat7.0版本以上无需配置环境变量。

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

   解决方法：右键项目——>Build Path——>Configure Build Path——>Build and Path——>Add Library

选择Server Runtinme，然后点击Next

如图选择Tomcat，前提是已在本机安装了tomcat，然后点击Finish。