gogoWebsite

Annotation is made on the field of the entity class, and you need to determine what type of this field is.

There are three types:

1. Verify the enum class – custom various Enum types

2. Verify the enum value – Integer type

3. Verify the enum name – String type

Using enumeration involves the issue of front- and back-end database type conversion, in contrast, Integer and String are simple to use.

Verify enum class – Customized various Enum types

Verify single enumeration class

Only act on a single enumeration class.

Through the implementation class of the annotation, it can be seen that the annotation only works onEnum<GenderEnum>Enumeration class.

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.*;

@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Constraint(validatedBy = {GenderValidator.class})
public @interface GenderValid {

	String message() default "Invalid GenderEnum type, please enter the correct enum type";

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

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

}

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

/**
 * @author jjsai
 * @date 2021/7/12 15:33
 **/
public class GenderValidator implements ConstraintValidator<GenderValid, Enum<GenderEnum>> {

	@Override
	public void initialize(GenderValid constraintAnnotation) {
	}

	@Override
	public boolean isValid(Enum<GenderEnum> value, ConstraintValidatorContext context) {
		if (value instanceof GenderEnum) {
			return true;
		}
		return false;
	}

}

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonValue;

import java.util.stream.Stream;

/**
 * @author jjsai
 * @date 2021/7/12 15:32
 **/
public enum GenderEnum {

	MALE(1,"male"),

	FEMALE(2,"female"),

	MONSTERS(3,"monster");

	private Integer code;

	private String desc;

	GenderEnum(Integer code,String desc) {
		this.code = code;
		this.desc = desc;
	}

	@JsonValue
	public Integer getCode() {
		return code;
	}

	public String getDesc() {
		return desc;
	}

	@JsonCreator
	public static GenderEnum getGender(Integer code) {
		if (code == null) {
			return null;
		}
		GenderEnum[] values = GenderEnum.values();
		return Stream.of(values).filter(it -> it.getCode().equals(code)).findAny().orElse(null);
	}

}

@EnumValid
private GenderEnum gender;

Verify various enumeration classes

It can be used on any enumeration class. You need to pass in the parameter target to specify which enumeration type.

Through the implementation class of the annotation, you can see that the annotation acts onObjectClass, any enumeration class can be checked here.

import javax.validation.ConstraintValidatorContext;

/**
 * @author jjsai
 * @date 2021/7/12 11:43
 **/
@Slf4j
public class EnumValidator implements ConstraintValidator<EnumValid, Object> {

	private EnumValid annotation;

	@Override
	public void initialize(EnumValid constraintAnnotation) {
		annotation = constraintAnnotation;
	}

	@Override
	public boolean isValid(Object value, ConstraintValidatorContext constraintValidatorContext) {
		Class<?> cls = annotation.target();
		Object[] objects = cls.getEnumConstants();
		for (Object obj : objects) {
			if (obj.equals(value)) {
				return true;
			}
		}
		return false;
	}
}

@EnumValid(target = GenderEnum.class)
private GenderEnum gender;

@EnumValid(target = TypeEnum.class)
private TypeEnum type;

Verify enum value – Integer type

Through the implementation class of the annotation, you can see that the annotation acts onIntegerkind.

import lombok.extern.slf4j.Slf4j;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

/**
 * @author jjsai
 * @date 2021/7/12 11:43
 **/
@Slf4j
public class EnumValidatorInteger implements ConstraintValidator<EnumValid, Integer> {

	private EnumValid annotation;

	@Override
	public void initialize(EnumValid constraintAnnotation) {

		annotation = constraintAnnotation;
	}

	@Override
	public boolean isValid(Integer value, ConstraintValidatorContext constraintValidatorContext) {
		boolean result = false;

		// Get the target parameter passed when annotation
		Class<?> cls = annotation.target();


		if (cls.isEnum() && value != null ) {

			// Get the enum list in this enum class
			Object[] objects = cls.getEnumConstants();
			try {

				for (Object obj : objects) {

					// obj to Enum 
                    // This method is a bit sloppy, you can use reflection, below
					String s = JacksonUtils.obj2json(obj);
					GenderEnum genderEnum = JacksonUtils.json2pojo(s, GenderEnum.class);

					// The field values ​​of the annotated are compared with the code of the enumeration instance. If the verification is consistent, the verification will be passed
					if (value.equals(genderEnum.getCode())) {
						result = true;
						break;
					}
				}
			} catch (Exception e) {
				result = false;
			}
		}
		return result;
	}

}

import lombok.extern.slf4j.Slf4j;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.lang.reflect.Method;

/**
 * @author jjsai
 * @date 2021/7/12 11:43
 **/
@Slf4j
public class EnumValidatorInteger implements ConstraintValidator<EnumValid, Integer> {

	private EnumValid annotation;

	@Override
	public void initialize(EnumValid constraintAnnotation) {

		annotation = constraintAnnotation;
	}

	@Override
	public boolean isValid(Integer value, ConstraintValidatorContext constraintValidatorContext) {
		boolean result = false;

		// Get the target parameter passed when annotation
		Class<?> cls = annotation.target();

		if (cls.isEnum() && value != null ) {

			// Get the enum list in this enum class
			Object[] objects = cls.getEnumConstants();
			try {
				// Get the getCode method object in the enumeration class
				Method method = cls.getMethod("getCode");
				for (Object obj : objects) {

					// Obj object reflection calls getCode method
					Object code = method.invoke(obj);

					// The field values ​​of the annotated are compared with the code of the enumeration instance. If the verification is consistent, the verification will be passed
					if (value.equals(code)) {
						result = true;
						break;
					}
				}
			} catch (Exception e) {
				result = false;
			}
		}
		return result;
	}

}

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonValue;

import java.util.stream.Stream;

/**
 * @author jjsai
 * @date 2021/7/12 15:32
 **/
public enum GenderEnum {

	MALE(1,"male"),

	FEMALE(2,"female"),

	MONSTERS(3,"monster");

	private Integer code;

	private String desc;

	GenderEnum(Integer code,String desc) {
		this.code = code;
		this.desc = desc;
	}

	@JsonValue
	public Integer getCode() {
		return code;
	}

	public String getDesc() {
		return desc;
	}

	@JsonCreator
	public static GenderEnum getGender(Integer code) {
		if (code == null) {
			return null;
		}
		GenderEnum[] values = GenderEnum.values();
		return Stream.of(values).filter(it -> it.getCode().equals(code)).findAny().orElse(null);
	}

}

import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author jjsai
 * @date 2021/7/11 19:05
 **/
@Data
@NoArgsConstructor
public class Student {

	private Long id;

	private String userName;

	private String telphone;

	@EnumValid(target = GenderEnum.class)
	private Integer gender;

}

Verify enum name – String type

Through the implementation class of the annotation, you can see that the annotation acts onStringkind.

import lombok.extern.slf4j.Slf4j;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * @author jjsai
 * @date 2021/7/12 11:43
 **/
@Slf4j
public class EnumValidatorString implements ConstraintValidator<EnumValid, String> {

	private EnumValid annotation;

	@Override
	public void initialize(EnumValid constraintAnnotation) {

		annotation = constraintAnnotation;
	}

	@Override
	public boolean isValid(String value, ConstraintValidatorContext constraintValidatorContext) {
		boolean result = false;
		Class<?> cls = annotation.target();
		if (cls.isEnum() && (value != null && value.trim().length() != 0)) {
			Object[] objects = cls.getEnumConstants();
			try {
				Method method = cls.getMethod("name");
				for (Object obj : objects) {
					Object code = method.invoke(obj);
					if (value.equals(code.toString())) {
						result = true;
						break;
					}
				}
			} catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
				result = false;
			}
		}
		return result;
	}
}

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonValue;

import java.util.stream.Stream;

/**
 * @author jjsai
 * @date 2021/7/12 15:32
 **/
public enum GenderEnumString {

	MALE(1, "male"),

	FEMALE(2, "female"),

	MONSTERS(3, "monster");

	private Integer code;

	private String desc;

	GenderEnumString(Integer code, String desc) {
		this.code = code;
		this.desc = desc;
	}

	public String getDesc() {
		return desc;
	}

	@JsonValue
	public Integer getCode() {
		return code;
	}

	@JsonCreator
	public static GenderEnumString getGender(String desc) {
		if (desc == null) {
			return null;
		}
		GenderEnumString[] values = GenderEnumString.values();
		return Stream.of(values).filter(it -> it.getDesc().equals(desc)).findAny().orElse(null);
	}

}

import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author jjsai
 * @date 2021/7/11 19:05
 **/
@Data
@NoArgsConstructor
public class Student {

	private Long id;

	private String userName;

	private String telphone;

	@EnumValid(target = GenderEnumString.class)
	private String gender;

}