Check工具类

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * @author : sungm
 * @since  : 2020-06-15
 */
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Check {

    boolean notNull() default false;

    boolean notEmpty() default false;

    boolean notBlank() default false;

    String regex() default "";

}

import demo.annotations.Check;

import java.lang.reflect.Field;
import java.util.Objects;
import java.util.regex.Pattern;

/**
 * @author : sungm
 * @since : 2020-06-15 16:01
 */
public class CheckUtils {

    private static final String EMPTY = "";

    public static <T> void check(T t) throws Exception {
        Class clazz = t.getClass();
        Field[] fields = clazz.getDeclaredFields();
        if (fields.length == 0) {
            return;
        }
        for (Field field : fields) {
            field.setAccessible(true);
            check(field.get(t), field);
        }
    }

    private static void check(Object value, Field field) throws Exception {
        Check check = field.getAnnotation(Check.class);
        if (Objects.isNull(check)) {
            return;
        }

        if (check.notNull() && Objects.isNull(value)) {
            throw new Exception("Field (" + field.getName() + ") cannot be null.");
        }
        if (check.notEmpty() && (Objects.isNull(value) || EMPTY.equals(value.toString()))) {
            throw new Exception("Field (" + field.getName() + ") cannot be empty.");
        }
        if (check.notBlank() && (Objects.isNull(value) || EMPTY.equals(value.toString().trim()))) {
            throw new Exception("Field (" + field.getName() + ") cannot be blank.");
        }
        checkRegex(field, value, check.regex());
    }

    private static void checkRegex(Field field, Object value, String regex) throws Exception {
        if (EMPTY.equals(regex) || Objects.isNull(value)) {
            return;
        }

        if (!Pattern.matches(regex, value.toString())) {
            throw new Exception("Wrong data format : Field (" + field.getName() + "), value  is : " + " value" + ", regex is : " + regex);
        }
    }

}

public class PersonDto {

    @Check(notBlank = true)
    private String name;
    @Check(notNull = true, regex = "\\d\\d")
    private Integer age;
    @Check(notBlank = true, regex = "男|女")
    private String sex;
    private String idCard;
    private String accessNumber;

    //省略了getter、setter方法
}

/**
 * @author : sungm
 * @since : 2020-06-15 17:50
 */
public class Main {

    public static void main(String[] args) throws Exception {
        PersonDto personDto = new PersonDto();
        personDto.setIdCard("0001");
        personDto.setName("孙广明");
        personDto.setSex("男");
        personDto.setAge(25);
        CheckUtils.check(personDto);
    }
}