springboot自定义注解: @Constraint实现对double类型进行大小比较

@Target({FIELD})
@Retention(RUNTIME)
@documented
@Constraint(validatedBy = {Doublevalidator.class}) // Doublevalidator具体实现校验方法
public @interface Doublevalue {
    String message() default "";
    double max();
    double min();
    // 不加以下两个参数会报错
    Class[] groups() default { };
    Class[] payload() default { };
}

public class Doublevalidator implements ConstraintValidator {

    private double max = 1;
    private double min = 1;
    private String message;

    @Override
    public void initialize(Doublevalue constraintAnnotation) {
        max = constraintAnnotation.max();
        min = constraintAnnotation.min();
        message = constraintAnnotation.message();
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext constraintValidatorContext) {
        if (value instanceof Double) { 
            Double v = (Double) value; // double类型作比较只能使用double的包装类
            if (v.compareTo(min) >= 0 && v.compareTo(max) <= 0) {
                return v.compareTo(min) >= 0 && v.compareTo(max) <= 0; // 判断数值是否在指定区间
            }
        }
        return false;
    }

}

public class MapVo {

    @NotNull(message = "经度值不能为空")
    @Doublevalue(max = 180.0, min = -180.0, message = "经度值范围: -180° ~ 180°")
    private Double wgLng;

    @NotNull(message = "纬度值不能为空")
    @Doublevalue(max = 90, min = -90, message = "纬度值范围: -90°~90°")
    private Double wgLat;

    @NotEmpty(message = "方法名不能为空")
    private String convert;
}

    @PostMapping("/mpConvert")
    public Result convert(@Valid MapVo mapVo) {
        System.out.println(mapVo);
    }