Spring MVC 学习之 - URL参数传递

清疚 2022-06-16 06:11 197阅读 0赞

在学习 Spring Mvc 过程中，有必要来先了解几个关键参数：

handler method 参数绑定常用的注解,我们根据他们处理的Request的不同内容部分分为四类：（主要讲解常用类型）

A、处理requet uri 部分（这里指uri template中variable，不含queryString部分）的注解：   @PathVariable;

B、处理request header部分的注解：   @RequestHeader, @CookieValue;

C、处理request body部分的注解：@RequestParam,  @RequestBody;

D、处理attribute类型是注解： @SessionAttributes, @ModelAttribute;

@Controller：

在类上注解，则此类将编程一个控制器，在项目启动 Spring 将自动扫描此类，并进行对应URL路由映射。

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      3 
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      5 
    </div> </td> 
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    <div style="margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:relative!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:auto!important; background:none!important"> 
     <div style="margin:0px!important; padding:0px 1em!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.8em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:auto!important; white-space:nowrap!important; background:none rgb(244,244,244)!important"> 
      <code style="margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.8em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; min-height:auto!important; color:gray!important; background:none!important">@Controller</code> 
     </div> 
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     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

@RequestMapping

指定URL映射路径，如果在控制器上配置 RequestMapping  ，具体请求方法也配置路径则映射的路径为两者路径的叠加 常用映射如:RequestMapping("url.html")

配置映射路径：

![复制代码][copycode.gif]

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

![复制代码][copycode.gif]

以上配置映射

http://\*\*\*:8080:web1/get\_alluser.html：

如在 @Controller添加 @RequestMapping(value = "/user"),则映射路径变成

http://\*\*\*:8080:web1/user/get\_alluser.html

@ResponseBody

将注解方法对应的字符串直接返回

@RequestParam

自动映射URL对应的参数到Action上面的数值，RequestParam 默认为必填参数。

@PathVariable

获取@RequestMapping 配置指定格式的URL映射参数

![复制代码][copycode.gif]

/*
          *   直接输出 HTML，或JSON 字符串
          *   请求路径:
          *       /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 被调用");
            String result = "直接返回内容  - key:" + key + ",key2:" + key2;
            System.out.println(result);
            return result;
        }

![复制代码][copycode.gif]

/*
         * RequestMapping 支持 Ant 风格的URL配置 ：
         *  请求路径：
         *     /urlinfo/geturlant/config.html?key=adddd
         */
        @ResponseBody
        @RequestMapping(value = "/geturlant/**.html")
        public String getUrlAnt(HttpServletRequest request) {
            String result = "?后面的参数为：" + request.getQueryString();
            return result;
        }

![复制代码][copycode.gif]

/*
         * 配置指定格式的URL，映射到对应的参数
         *   请求路径：/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", "获取到的Id:" + id + ",menuId:" + menuId);
            return mode;
        }

![复制代码][copycode.gif]

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

![复制代码][copycode.gif]

/*
         *   写入 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 写入成功");
            return  mode ;
        }

![复制代码][copycode.gif]

/*
           *  通过 @CookieValue 获取对应的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;
        }

![复制代码][copycode.gif]

/* 
         * 将 Servlet Api 作为参数传入 
         *   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;
    
        }

![复制代码][copycode.gif]

/*
         *   根据URL传入的参数实例化对象
         *   
         *   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 = "用户ID：" + user.getUserId().toString() + ",用户名:"
                    + user.getUserName().toString();
            ModelAndView mode = new ModelAndView(ShowMsg);
            mode.addObject("msg", "result=" + result.toString());
            return mode;
        }

![复制代码][copycode.gif]

实现页面跳转：

![复制代码][copycode.gif]

/* 
         * 实现页面跳转
         * /web1/urlinfo/redirectpage.html
         * */
        @RequestMapping("/redirectpage.html")
        public String RedirectPage()
        {
            return  "redirect:getcookies.html?r=10"; 
                    
        }

![复制代码][copycode.gif]

直接回传JSON

请求的URL地址一定是以.json结尾，否则异常

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 ()

回传实体：

![复制代码][copycode.gif]

@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;
          
         
    }

![复制代码][copycode.gif]

回传 action

![复制代码][copycode.gif]

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

![复制代码][copycode.gif]

请求：

/web1/urlinfo/getuser.json

输出：

{"userId":100,"userName":"王坤"}

一只站在树上的鸟儿，从来不会害怕树枝会断裂，因为它相信的不是树枝，而是它自己的翅膀。与其每天担心未来，不如努力做好现在。

[copycode.gif]: /images/20220616/c2078d4ed72242768c8b4aad58b24633.png