Spring boot @ModelAttribute标注的实现
作者：麦穗儿
这篇文章主要介绍了Spring boot @ModelAttribute标注的实现，文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值，需要的朋友们下面随着小编来一起学习学习吧
@ModelAttribute可以注释方法和参数
@ModelAttribute注释方法
@ModelAttribute注释方法该方法会在controller的所有方法之前被执行。通过Model将value设定到相应的key中。
(1)注释返回值为void的方法，通过传入Model添加属性值
@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)注释返回值为具体类型的。通过添加属性（属性名为返回值的头字母小写,例如返回值为Group，属性为group）将返回值添加
实际结果类似与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)指定属性的名称
//类似于Model.addAttribute("defaultuser", User)
@ModelAttribute("defaultuser")
public User createDefaultUser() {
return new User("defaultUsr","SH", 22, true);
}
@GetMapping(path="/checkdefaultuser")
@ResponseBody
public 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注释方法的参数
@ModelAttribute("defaultuser")
public User createDefaultUser() {
return new User("defaultUsr","SH", 22, true);
}
@GetMapping(path="/checkdefaultuser")
@ResponseBody
public String checkDefaultUser(@ModelAttribute("defaultuser") User dfUsr) {
String dfUsrStr = "Default user("+dfUsr.name + "," + dfUsr.address + "," + dfUsr.age + "," + dfUsr.isMan + ")";
System.out.println(dfUsrStr);
return dfUsrStr;
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。