在學習 Spring Mvc 過程中，有必要來先了解幾個關鍵引數：

   @Controller：

         在類上註解，則此類將程式設計一個控制器，在專案啟動 Spring 將自動掃描此類，並進行對應URL路由對映。

@Controller
public class UserAction 
{
   
}

　 @RequestMapping

         指定URL對映路徑，如果在控制器上配置 RequestMapping  ，具體請求方法也配置路徑則對映的路徑為兩者路徑的疊加 常用對映如:RequestMapping("url.html")

        配置對映路徑：

@Controller
public class UserAction 
{
    @RequestMapping(value = "/get_alluser.html")
   public ModelAndView GetAllUser(String Id)
   {
   }
}

     以上配置對映

 　　  http://***:8080:web1/get_alluser.html：

         如在 @Controller新增 @RequestMapping(value = "/user"),則對映路徑變成

          http://***:8080:web1/user/get_alluser.html

   @ResponseBody

      將註解方法對應的字串直接返回

   @RequestParam

      自動對映URL對應的引數到Action上面的數值，RequestParam 預設為必填引數。

   @PathVariable

      獲取@RequestMapping 配置指定格式的URL對映引數

     /*
      *   直接輸出 HTML，或JSON 字串
      *   請求路徑:
      *       /web1/urlinfo/getcontent.html?key=rhythmk
      *      /web1/urlinfo/getcontent.json?key=rhythmk
      * 
 
*/
    @ResponseBody
    @RequestMapping(value = "/getcontent.**")
    public String GetContent(
            @RequestParam("key") String key,
            @RequestParam(value = "key2", required = false, defaultValue = "defaultValue") String key2) {
        System.out.println("getcontent 被呼叫");
        String result = "直接返回內容  - key:" + key + ",key2:" + key2;
        System.out.println(result);
        return result;
    }

    /*
     * RequestMapping 支援 Ant 風格的URL配置 ：
     *  請求路徑：
     *     /urlinfo/geturlant/config.html?key=adddd
     */
    @ResponseBody
    @RequestMapping(value = "/geturlant/**.html")
    public String getUrlAnt(HttpServletRequest request) {
        String result = "?後面的引數為：" + request.getQueryString();
        return result;
    }

    /*
     * 配置指定格式的URL，對映到對應的引數
     *   請求路徑：/web1/urlinfo/geturlparam/12_123.html
     *     
     * */
    
    @RequestMapping(value = "/geturlparam/{id}_{menuId}.html")
    public ModelAndView getUrlParam(@PathVariable("id") String id,
            @PathVariable("menuId") String menuId) {
        ModelAndView mode = new ModelAndView(ShowMsg);
        mode.addObject("msg", "獲取到的Id:" + id + ",menuId:" + menuId);
        return mode;
    }

    /*
     * 只接收Post 請求
     */
    @ResponseBody
    @RequestMapping(value = "/posturl.html", method = RequestMethod.POST)
    public String UrlMethod(@RequestParam String id) {
        return "只能是Post請求,獲取到的Id:" + id;
    }

    /*
     *   寫入 cookie
     * */ 
    @RequestMapping("/writecookies.html")
    public ModelAndView writeCookies(@RequestParam String value,
            HttpServletResponse response) {

        response.addCookie(new Cookie("key", value));
        ModelAndView mode = new ModelAndView(ShowMsg);
        mode.addObject("msg", "cookies 寫入成功");
        return  mode ;
    }

      /*
       *  通過 @CookieValue 獲取對應的key的值
       * */
    @RequestMapping("/getcookies.html")
    public ModelAndView getCookie(@CookieValue("key") String cookvalue) {
        ModelAndView mode = new ModelAndView(ShowMsg);
        mode.addObject("msg", "cookies=" + cookvalue);
        return mode;
    }

    /* 
     * 將 Servlet Api 作為引數傳入 
     *   可以在action中直接使用  HttpServletResponse，HttpServletRequest
     * */
    @RequestMapping("/servlet.html")
    public String Servlet1(HttpServletResponse response,
            HttpServletRequest request) {

        Boolean result = (request != null && response != null);
        ModelAndView mode = new ModelAndView();
        mode.addObject("msg", "result=" + result.toString());
        return ShowMsg;

    }

    /*
     *   根據URL傳入的引數例項化物件
     *   
     *   如： http://127.0.0.1:8080/web1/urlinfo/getobject.html?UserId=1&UserName=ad
     * */
    @RequestMapping("getobject.html")
    public ModelAndView getObject(UserInfo user) {
        String result = "使用者ID：" + user.getUserId().toString() + ",使用者名稱:"
                + user.getUserName().toString();
        ModelAndView mode = new ModelAndView(ShowMsg);
        mode.addObject("msg", "result=" + result.toString());
        return mode;
    }

 實現頁面跳轉：

    /* 
     * 實現頁面跳轉
     * /web1/urlinfo/redirectpage.html
     * */
    @RequestMapping("/redirectpage.html")
    public String RedirectPage()
    {
        return  "redirect:getcookies.html?r=10"; 
                
    }

直接回傳JSON

    請求的URL地址一定是以.json結尾，否則異常

     Failed to load resource: the server responded with a status of 406 (Not Acceptable) ： The resource identified by this request is only capable of generating responses with characteristics not acceptable according to the request "accept" headers () 

回傳實體：

@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class UserInfo {

      private  Integer UserId;
      public Integer getUserId() {
        return UserId;
    }
    public void setUserId(Integer userId) {
        UserId = userId;
    }
    public String getUserName() {
        return UserName;
    }
    public void setUserName(String userName) {
        UserName = userName;
    }
    private String UserName;
      
     
}

 回傳 action

@ResponseBody
    @RequestMapping("/getuser.json")
    public UserInfo  GetUser()
    {
        System.out.println("getuser");
        UserInfo model=new  UserInfo();
        model.setUserId(100);
        model.setUserName("王坤");
        return model;
    }

請求：

/web1/urlinfo/getuser.json

輸出：

{"userId":100,"userName":"王坤"}