Spring MVC 学习 之 - URL参数传递详解

在学习 Spring Mvc 过程中，有必要来先了解几个关键参数：

@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。

@Controller

public class UserAction{ }

@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：

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

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

 /*
   *  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;
  }

 /*
   * 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;
  } 

 /*
   * 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;
  } 

  /*
   * 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;
  } 

  /*
   *  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 ;
  }

  /*
    * 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;
  } 

  /*
   * 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;

  }

  /*
   *  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;
  } 

实现页面跳转：

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

  } 

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：

@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;

}

回传 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;
  }

请求：

/web1/urlinfo/getuser.json

输出：

 {"userId":100,"userName":"王坤"}

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