List校验，使用原生@Size即可实现，下诉只是范例

自定义注解

@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = ListValidator.class)
public @interface ListValid {

    int min() default 0;

    int max() default Integer.MAX_VALUE;

    String message() default "";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};

}

自定义注解校验实现类

@Component
public class ListValidator implements ConstraintValidator<ListValid, List> {

    private int minLength;
    private int maxLength;

    @Override
    public void initialize(ListValid listValid) {
        minLength = listValid.min();
        maxLength = listValid.max();
    }

    @Override
    public boolean isValid(List target, ConstraintValidatorContext constraintValidatorContext) {
        int size = null == target ? 0 : target.size();
        if (0 != minLength && null == target) {
            return false;//不允许为空，List为空
        }
        if (size < minLength) {
            return false;//长度小于最小值
        }
        if (0 != maxLength && size > maxLength) {
            return false;//指定最大长度，且长度大于最大值
        }
        return true;
    }

}

应用

 	@Valid
    @ListValid(min = 1,message = "请编辑后保存")
    private List<BO> BOList;