2018.10.10 Java的The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path 错误

我们在用Eclipse进行Java web开发时，可能会出现这样的错误：The superclass javax.servlet.http.HttpServlet was not found on the Java Build Path。我们该怎么解决这个问题呢？

解决办法是重新构建路径就是Build Path 然后添加Server Runtime 就是服务器运行环境