SpringBoot Validation 自定义校验器

先给出官方文档的链接：Spring Boot Validation

需要设定自己的校验器，这里我需要对两个属性进行相互校验

先给出代码

kotlin

package com.example.demo.annotation

import jakarta.validation.Constraint
import jakarta.validation.ConstraintValidator
import jakarta.validation.ConstraintValidatorContext
import jakarta.validation.Payload
import kotlin.reflect.KClass
import kotlin.reflect.full.memberProperties
import kotlin.reflect.jvm.isAccessible

@Target(AnnotationTarget.CLASS)
@Retention(AnnotationRetention.RUNTIME)
@Constraint(validatedBy = [IconValueValidator::class])
annotation class IconValidation(
    val message: String = "Icon validation failed",
    val groups: Array<KClass<*>> = [],
    val payload: Array<KClass<out Payload>> = [],
    val iconTypeField: String = "iconType",
    val iconValueField: String = "iconValue"
)

class IconValueValidator: ConstraintValidator<IconValidation, Any> {
    private var iconTypeField: String = "iconType"
    private var iconValueField: String = "iconValue"

    override fun initialize(constraintAnnotation: IconValidation) {
        iconTypeField = constraintAnnotation.iconTypeField
        iconValueField = constraintAnnotation.iconValueField
    }

    override fun isValid(obj: Any?, context: ConstraintValidatorContext): Boolean {
        if (obj == null) return true

        try {
            val kClass = obj::class
            val iconTypeProp = kClass.memberProperties.find { it.name == "iconType" }
            val iconValueProp = kClass.memberProperties.find { it.name == "iconValue" }

            iconTypeProp?.isAccessible = true
            iconValueProp?.isAccessible = true

            val iconType = iconTypeProp?.call(obj)?.toString()
            val iconValue = iconValueProp?.call(obj)?.toString()
            if (iconType == null || iconValue == null) return true

            val isValid = when(iconType) {
                "font" -> iconValue.matches(Regex("^[a-zA-Z0-9_-]+$"))
                "image" -> iconValue.matches(Regex("^(https?|ftp)://[^\\s/$.?#].[^\\s]*$"))
                "svg" -> iconValue.matches(Regex("^<svg[^>]*>.*</svg>$"))
                else -> false
            }

            if (!isValid) {
                context.disableDefaultConstraintViolation()
                context.buildConstraintViolationWithTemplate("Invalid icon value for type $iconType")
                    .addPropertyNode("iconValue")
                    .addConstraintViolation()
            }
            return isValid
        } catch (e: Exception) {
            println("Error during icon validation: ${e.message}")
            return false
        }
    }
}

这个校验器会根据 iconType 的值来校验 iconValue 的格式是否正确

因为我的校验器需要在多个类中使用，主要用来校验前端传递的 dto 的准确性, 所以这里使用了反射实现，但是性能应该会有损耗，但是我目前还没有找到更好的方法来实现这个校验器接下来是使用这个校验器的示例：

kotlin

import com.example.demo.annotation.IconValidation
import jakarta.validation.constraints.NotBlank
import jakarta.validation.constraints.Pattern

@IconValidation
data class CategoryCreateDto (
    var name: String? = null,
    var comment: String? = null,
    @field:NotBlank
    @field:Pattern(regexp = "^(font|image|svg)$")
    var iconType: String? = null,
    @field:NotBlank
    var iconValue: String? = null,
)

SpringBoot Validation 自定义校验器 ​

SpringBoot Validation 自定义校验器