Spring MVC中参数校验失败示例-蒲公英云

Spring MVC中参数校验失败示例

在Spring MVC中，参数校验通常通过ActionController的@Validated注解以及Validator接口实现。如果校验失败，会抛出ValidationException。

以下是一个参数校验失败的示例：

创建一个实体类（User.java）：

public class User {
    @NotBlank(message = "Username cannot be blank"))
    private String username;
    // getters and setters
}

在ActionController中使用校验（UserController.java）：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
@Controller
public class UserController {
    @Autowired
    private UserService userService;
    // action methods for GET and POST
    @GetMapping("/user")
    public String getUser(ModelMap model) {
        User user = userService.getUser(); // assume valid return
        model.addAttribute("user", user);
        return "user Profile"; // view name
    }
    @PostMapping("/save-user")
    public String saveUser(@Validated @BindingResult User user, ModelMap model) {
        if (!user.getName().equals(user.getUsername()))) { // validation error
            model.addAttribute("error", "Username and Name must match");
            return "save-user"; // view name to show error message
        }
        userService.saveUser(user); // assume valid return
        model.addAttribute("success", "User saved successfully!");
        return "user-profile-success"; // view name to show success message
    }
}