Springboot中怎么實現(xiàn)@ModelAttribute標注

本篇文章給大家分享的是有關Springboot中怎么實現(xiàn)@ModelAttribute標注，小編覺得挺實用的，因此分享給大家學習，希望大家閱讀完這篇文章后可以有所收獲，話不多說，跟著小編一起來看看吧。

@ModelAttribute可以注釋方法和參數(shù)

@ModelAttribute注釋方法

@ModelAttribute注釋方法該方法會在controller的所有方法之前被執(zhí)行。通過Model將value設定到相應的key中。

(1)注釋返回值為void的方法，通過傳入Model添加屬性值

@RestController@RequestMapping("/usrcontroller")public class UserController {  UserService us = new UserService();  @ModelAttribute  public void findUserById(@RequestParam Long uid, Model model) {    model.addAttribute("user", us.getUser(uid));  }  @GetMapping(path="/getuser")  @ResponseBody  public String getUser(Model model) {    User u = (User)(model.getAttribute("user"));    System.out.println(u.name);    return u.name;  }}

(2)注釋返回值為具體類型的。通過添加屬性（屬性名為返回值的頭字母小寫,例如返回值為Group，屬性為group）將返回值添加實際結果類似與model.addAttribute("returnvaluename", var);

@RestController@RequestMapping("/groupcontroller")public class GroupController {  @ModelAttribute  public Group getGroupId(@RequestParam Long gid) {    Group g = new Group();    g.groupName = "group_"+gid;    g.groupId = gid;    return g;    //same as Model.addAttribute("group", g)  }  @GetMapping(path="/getgroup")  @ResponseBody  public String getGroup(Model model) {    Group g = (Group)model.getAttribute("group");    String gStr = "group(id:" + g.groupId + "," + g.groupName + ")";    System.out.println(gStr);    return gStr;  }}

(3)指定屬性的名稱

//類似于Model.addAttribute("defaultuser", User)@ModelAttribute("defaultuser")public User createDefaultUser() {  return new User("defaultUsr","SH", 22, true);}@GetMapping(path="/checkdefaultuser")@ResponseBodypublic String checkDefaultUser(@ModelAttribute("defaultuser") User dfUsr) {  String dfUsrStr = "Default user("+dfUsr.name + "," + dfUsr.address + "," + dfUsr.age + "," + dfUsr.isMan + ")";  System.out.println(dfUsrStr);  return dfUsrStr;}

@ModeAttribute注釋方法的參數(shù)

@ModelAttribute("defaultuser")public User createDefaultUser() {  return new User("defaultUsr","SH", 22, true);}@GetMapping(path="/checkdefaultuser")@ResponseBodypublic String checkDefaultUser(@ModelAttribute("defaultuser") User dfUsr) {  String dfUsrStr = "Default user("+dfUsr.name + "," + dfUsr.address + "," + dfUsr.age + "," + dfUsr.isMan + ")";  System.out.println(dfUsrStr);  return dfUsrStr;}

以上就是Springboot中怎么實現(xiàn)@ModelAttribute標注，小編相信有部分知識點可能是我們?nèi)粘９ぷ鲿姷交蛴玫降?。希望你能通過這篇文章學到更多知識。更多詳情敬請關注億速云行業(yè)資訊頻道。