Circular view path [***]: would dispatch back to the current handler URL [/springmvc_01/hello] ag

背景：IDEA中新建springmvc程序，运行tomcat报错

Circular view path [hello]: would dispatch back to the current handler URL [/springmvc_01/hello] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.)

运行tomcat。浏览器报错。详细错误信息如下

HTTP Status 500 – Internal Server Error

Type Exception Report
Message Circular view path [hello]: would dispatch back to the current handler URL [/springmvc_01/hello] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.)
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception 
javax.servlet.ServletException: Circular view path [hello]: would dispatch back to the current handler URL [/springmvc_01/hello] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.)
	org.springframework.web.servlet.view.InternalResourceView.prepareForRendering(InternalResourceView.java:205)
	org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:145)
	org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
	org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1286)
	org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1041)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:984)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Note The full stack trace of the root cause is available in the server logs.

Apache Tomcat/7.0.93

解决方法：

是control类导包错误（这个包因为ModelAndView）

发现是import org.springframework.web.portlet.ModelAndView;有问题，本应该是import org.springframework.web.servlet.ModelAndView;