springboot freemarker 国际化只显示中文，点击英文切换不起作用？

为什么我这个国际化，点击切换按钮英文不起作用？只显示中文

最后附上controller代码

package com.yadu.example.demo.controller;

import com.yadu.example.demo.entity.User;
import com.yadu.example.demo.service.LocaleMessageSourceService;
import com.yadu.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.MessageSource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;

import javax.annotation.Resource;

@RestController
public class Controller {

    @Autowired
    private UserService userService;

    @Autowired
    private MessageSource messageSource;

    /**
     * 获取国际化信息
     */
    @Resource
    private LocaleMessageSourceService localeMessageSourceService;

    @GetMapping("/hi")
    public String index(){
        return "hello spring boot";
    }
    @RequestMapping("/users/{userId}")
    public User getUser(@PathVariable("userId") int userId){
        User user = userService.getById(userId);
        return user;
    }

    /**
     * freemarker模板
     * @param modelAndView
     * @return
     */
    @RequestMapping(value = "/indexFre")
    public ModelAndView indexFre(ModelAndView modelAndView) {
        //设置返回的页面名称
        modelAndView.setViewName("indexFre");
        //要返回在页面的数据
      /*  List<User> userList =  userService.getUsers();
        modelAndView.addObject("userList", userList);*/
        return modelAndView;
    }


    @RequestMapping("/hello")
    public ModelAndView hello(ModelAndView modelAndView){
        String msg3 = localeMessageSourceService.getMessage("welcome");
        modelAndView.setViewName("hello");
        return  modelAndView;

    }



   /* @RequestMapping("/changeSessionLanauage")
    public String changeSessionLanauage(HttpServletRequest request, HttpServletResponse response, String lang){
        System.out.println(lang);
        LocaleResolver localeResolver = RequestContextUtils.getLocaleResolver(request);
        if("zh".equals(lang)){
            localeResolver.setLocale(request, response, new Locale("zh", "CN"));
        }else if("en".equals(lang)){

            localeResolver.setLocale(request, response, new Locale("en", "US"));
        }
        return "redirect:/hello";
    }*/
}

https://blog.csdn.net/qq_17025903/article/details/80883270
可以用百度翻译接口