Servlet eroor：HTTP method GET is not supported by this URL
错误提示：
type: Status report
message: HTTP method GET is not supported by this URL
description: The specified HTTP method is not allowed for the requested resource (HTTP method GET is not supported by this URL).
原因：
1，继承自HttpServlet的Servlet没有重写对于请求和响应的处理方法：doGet或doPost等方法；默认调用父类的doGet或doPost等方法；
2，父类HttpServlet的doGet或doPost等方法覆盖了你重写的doGet或doPost等方法；
解决办法:
1，子类重写doGet或doPost等方法；
2，在你扩展的Servlert中重写doGet或doPost等方法来处理请求和响应时 不要调用父类HttpServlet的doGet或doPost等方法，即去掉super.doGet(request, response)和super.doPost(request, response);