HTTP 415错误-Unsupported media type详解

<script>
	jQuery(function($){
	var urlStr = "<%=request.getContextPath()%>/user/GetUser";
		var user = {
			"id" : 6,
			"userName" : "小红",
			"password" : "123",
			"age" : 12
		};
		$.ajax({
			url : urlStr,
			type : "POST",
			data : JSON.stringify(user), //转JSON字符串  
			dataType : 'json',
			contentType : 'application/json;charset=UTF-8', //contentType很重要     
			success : function(result) {
				console.log(result);
				//alert(result);
				//data = eval("(" + result + ")");
				//alert(data);
				$("#a").html(result.userName);
			}
		});
	});
</script>

package com.cn.hnust.controller;
 
import javax.servlet.http.HttpServletRequest;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
 
import com.cn.hnust.domain.User;
import com.cn.hnust.service.IUserService;
 
@Controller
@RequestMapping("/user")
public class UserController {
 
	@Autowired
	private IUserService userService;
 
	@RequestMapping("/showUser")
	public String toIndex(HttpServletRequest request, Model model) {
		// int userId = Integer.parseInt(request.getParameter("id"));
		// User user = this.userService.getUserById(userId);
		// model.addAttribute("user", user);
		return "showUser";
	}
 
	@RequestMapping(value = "/GetUser", method = RequestMethod.POST)
	public @ResponseBody
	User GetUser(@RequestBody User user) {
		user.setUserName("Wei");
		return user;
	}
 
}

<bean
		class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
		<property name="order" value="1" />
		<property name="mediaTypes">
			<map>
				<entry key="json" value="application/json" />
				<entry key="xml" value="application/xml" />
				<entry key="htm" value="text/html" />
			</map>
		</property>
 
		<property name="defaultViews">
			<list>
				<!-- JSON View -->
				<bean
					class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
				</bean>
			</list>
		</property>
		<property name="ignoreAcceptHeader" value="true" />
	</bean>

MappingJacksonJsonView

MappingJackson2JsonView