如何在spring-hibernate中动态地通过字段验证

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.2.0.Final</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

public class User {
    @NotNull
    private String username;
    
    @Size(min = 6, max = 20)
    private String password;
    
    // 其他字段...
    
    // Getters and setters...
}

@RestController
public class UserController {
    @PostMapping("/users")
    public ResponseEntity<String> createUser(@Valid @RequestBody User user, BindingResult bindingResult) {
        if (bindingResult.hasErrors()) {
            // 处理验证错误
            return ResponseEntity.badRequest().body("Validation failed");
        }
        
        // 保存用户到数据库
        // ...
        
        return ResponseEntity.ok("User created");
    }
}