Research on the technical principles of the Bean Validation Scala framework in the Java class library
Research on the technical principles of the Bean Validation Scala framework in the Java class library
Introduction:
Bean Validation is an important class library in Java, which provides developers with a simple and flexible way to verify the state of the JavaBean object.Since Scala is a programming language running on the Java virtual machine, developers can use the Bean Validation framework to verify the objects in the SCALA application.This article will discuss the technical principles of using the Bean Validation Scala framework in the Java library and explain its usage method through code examples.
Basic principle of the Bean Validation framework:
The basic principle of Bean Validation is to ensure that the object's status is complied with expectations by verifying the annotations of the JavaBean object.Developers can use annotations to define verification rules on the attributes of the JavaBean class, and then perform verification operations through the Bean Validation framework.
Use the Bean Validation framework in SCALA:
In order to use the Bean Validation framework in SCALA, we need to add dependence on Bean Validation.You can introduce the Bean Validation framework by adding the following Maven dependence:
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>6.2.0.Final</version>
</dependency>
In Scala, we can use annotations to define verification rules.The following is an example that shows how to use the annotation of Bean Validation in SCALA to verify a user object:
scala
import javax.validation.constraints.{Email, NotEmpty}
class User {
@Notempty (Message = "Username cannot be empty")
var username: String = ""
@Notempty (MESSAGE = "Password cannot be empty")
var password: String = ""
@Email (Message = "Email format is incorrect")
var email: String = ""
}
In the above examples, we use the verification rules of `username`,` Password` and `email`.
Expanded Bean Validation's Verification Rules:
In addition to the verification rules provided by the annotation, we can also expand the Bean Validation framework to meet specific needs.The following is an example that shows how to customize verification rules:
scala
import javax.validation._
import javax.validation.spi.ValidationProvider
class CustomValidator extends javax.validation.Validator {
override def validate[T](arg: T, cascaded: Class[_]*): Set[ConstraintViolation[T]] = {
// Customized verification logic
Set.empty
}
// Other necessary methods
}
class CustomValidationProvider extends ValidationProvider[CustomValidator] {
override def createSpecializedValidatorFactory(): ConfiguredValidatorFactory = ???
override def getDefaultConfiguration(): BootstrapConfiguration = ???
override def getDefaultValidatorFactory(): ValidatorFactory = ???
override def getValidationProviderResolver(): ValidationProviderResolver = ???
}
In the above example, we created a customized verification device called `CustomValidator`, and implemented the` value method to define custom logic.Then, we also implemented the `CustomValidationProvider` class to provide the configuration of a custom verification device.
in conclusion:
This article studies the technical principles of the Bean Validation Scala framework in the Java library.By using the Bean Validation framework, we can easily verify in the SCALA application.Developers can use annotations to define verification rules, and they may expand the Bean Validation framework to meet specific needs.Although SCALA is a programming language different from Java, developers can still easily implement object verification by using the Bean Validation framework.
