别再用 if 校验参数了，太Low！这才是专业的 SpringBoot 参数校验方式！

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

@Data
public class Student {
    @NotBlank(message = "姓名必须填")
    private String name;
    @NotNull(message = "年龄必须填写")
    @Range(min = 1,max =50, message = "年龄取值范围1-50")
    private Integer age;
    @NotEmpty(message = "成绩必填")
    private List<Double> scores;
}

@RestController
@RequestMapping("/student")
public class StudentController {
    @PostMapping("/add")
    public Rest<?> addStudent(@Valid @RequestBody Student student) {
        return RestBody.okData(student);
    }
}

POST /student/add HTTP/1.1
Host: localhost:8888
Content-Type: application/json
{
    "name": "felord.cn",
    "age": 77,
    "scores": [
        55
    ]
}

@GetMapping("/get")
public Rest<?> getStudent(@Valid Student student) {
    return RestBody.okData(student);
}

GET /student/get?name=felord.cn&age=12 HTTP/1.1
Host: localhost:8888

@NotNull(message = "年龄必须填写")
@Range(min = 1,max =50, message = "年龄取值范围1-50")
private Integer age;

import org.hibernate.validator.constraints.Range;
import javax.validation.Constraint;
import javax.validation.Payload;
import javax.validation.ReportAsSingleViolation;
import javax.validation.constraints.NotNull;
import javax.validation.constraintvalidation.SupportedValidationTarget;
import javax.validation.constraintvalidation.ValidationTarget;
import java.lang.annotation.*;
/**
 * @author a
 * @since 17:31
 **/
@Constraint(
        validatedBy = {}
)
@SupportedValidationTarget({ValidationTarget.ANNOTATED_ELEMENT})
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.FIELD,
        ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR,
        ElementType.PARAMETER, ElementType.TYPE_USE})
@NotNull
@Range(min = 1, max = 50)
@Documented
@ReportAsSingleViolation
public @interface Age {
    // message 必须有
    String message() default "年龄必须填写，且范围为 1-50 ";
    // 可选
    Class<?>[] groups() default {};
    // 可选
    Class<? extends Payload>[] payload() default {};
}

public enum Colors {
    RED, YELLOW, BLUE
}

/**
 * @author felord.cn
 * @since 17:57
 **/
public class ColorConstraintValidator implements ConstraintValidator<Color, String> {
    private static final Set<String> COLOR_CONSTRAINTS = new HashSet<>();
    @Override
    public void initialize(Color constraintAnnotation) {
        Colors[] value = constraintAnnotation.value();
        List<String> list = Arrays.stream(value)
                .map(Enum::name)
                .collect(Collectors.toList());
        COLOR_CONSTRAINTS.addAll(list);
    }
    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        return COLOR_CONSTRAINTS.contains(value);
    }
}

/**
 * @author felord.cn
 * @since 17:55
 **/
@Constraint(validatedBy = ColorConstraintValidator.class)
@Documented
@Target({ElementType.METHOD, ElementType.FIELD,
        ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR,
        ElementType.PARAMETER, ElementType.TYPE_USE})
@Retention(RetentionPolicy.RUNTIME)
public @interface Color {
    // 错误提示信息
    String message() default "颜色不符合规格";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
    // 约束的类型
    Colors[] value();
}

@Data
public class Param {
    @Color({Colors.BLUE,Colors.YELLOW})
   private String color;
}

GET /student/color?color=CAY HTTP/1.1
Host: localhost:8888

@GetMapping("/color")
public Rest<?> color(@Valid @Color({Colors.BLUE,Colors.YELLOW}) String color) {
    return RestBody.okData(color);
}

@GetMapping("/rest/{color}")
public Rest<?> rest(@Valid @Color({Colors.BLUE, Colors.YELLOW}) @PathVariable String color) {
    return RestBody.okData(color);
}

/**
 * 集合类型参数元素.
 *
 * @param student the student
 * @return the rest
 */
@PostMapping("/batchadd")
public Rest<?> batchAddStudent(@Valid @RequestBody List<Student> student) {
    return RestBody.okData(student);
}

@Data
public class Student {
    @NotBlank(message = "姓名必须填")
    private String name;
    @Age
    private Integer age;
    @NotEmpty(message = "成绩必填")
    private List<Double> scores;
    @NotNull(message = "学校不能为空")
    private School school;
}
@Data
public class School {
    @NotBlank(message = "学校名称不能为空")
    private String name;
    @Min(value = 0,message ="校龄大于0" )
    private Integer age;
}

@Data
public class Student {
    @NotBlank(message = "姓名必须填")
    private String name;
    @Age
    private Integer age;
    @NotEmpty(message = "成绩必填")
    private List<Double> scores;
    @Valid
    @NotNull(message = "学校不能为空")
    private School school;
}