java - spring-mvc 运行报错 No adapter for handler-PHP中文网问答

配置了DispatcherServlet的detectAllHandlerMappings属性为true；
spring-mvc.xml也有声明：


    
        
                
        
    


**访问：http://localhost:8080/demo/index 一直报错：**
javax.servlet.ServletException: No adapter for handler [com.wch.controller.UserController@20142abf]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler
org.springframework.web.servlet.DispatcherServlet.getHandlerAdapter(DispatcherServlet.java:1136)

下面是Controller部分：
package com.wch.controller;

import com.wch.entity.User;
import com.wch.service.IUserService;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;

@Controller
public class UserController {

@Resource
private IUserService userService;

@RequestMapping(value = "/index", method = RequestMethod.GET)
public String toIndex(HttpServletRequest request, Model model)
{
    String name = (String)request.getParameter("name");
    User user = this.userService.getUser(name);
    model.addAttribute("user",user);
    return  "index";
}

}