SpringBoot自定义validation验证

注解类

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER})
@Retention(RUNTIME)
@Documented
@Constraint(validatedBy = StringLengthValidator.class)
public @interface StringLength {

    // 必须加
    String message() default "{javax.validation.constraints.NotNull.message}";

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

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

    int minLength() default 0;

    int maxLength() default 16;
}

验证实现类

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.util.Objects;

public class StringLengthValidator implements ConstraintValidator<StringLength, Object> {

    private StringLength stringLength;

    @Override
    public void initialize(StringLength constraintAnnotation) {
        this.stringLength = constraintAnnotation;
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext context) {
        if (Objects.isNull(value)) {
            return true;
        }
        if (null != stringLength) {
            int length = String.valueOf(value).length();
            int maxLen = stringLength.maxLength(),
                    minLen = stringLength.minLength();
            return length >= minLen && length <= maxLen;
        }
        return false;
    }
}