BEAN VALIDATION Scala framework example code commonly used in the Java class library

Title: Bean Validation Scala framework for the commonly used in the Java class library Introduction: Bean Validation is a common Java standard that is used to verify the effectiveness of the object in the application.Starting from Java Ee 6, it has become part of the Java class library and is widely used in daily development.This article will introduce a common example code that uses the Bean Validation framework in SCALA, and how to use it in practical applications to verify the attributes of the object. 1. What is Bean Validation? Bean value is a framework for verifying the JavaBeans property.It provides a set of annotations and APIs to help developers verify objects at runtime.This framework allows developers to define custom verification logic and declare sexual constraints on attributes.By using Bean Validation, developers can ensure that objects in the application meet specific verification rules. 2. Use Bean Validation in SCALA Bean value can be easily used in SCALA.First, ensure that the relevant dependencies are included in the construction document of the project.Example configuration using Gradle for construction is as follows: groovy dependencies { implementation 'org.hibernate:hibernate-validator:6.0.16.Final' implementation 'org.scala-lang:scala-library:2.13.6' } Once the configuration of the file is built, you can start using Bean Validation in SCALA. Third, sample code Suppose we have a Person class that includes names and ages.We want to verify these attributes so that the name cannot be NULL or empty string, and the age must be between 0 and 120.Below is an example code using the Bean Validation framework: scala import javax.validation.{ConstraintViolation, Validation, Validator} case class Person(name: String, age: Int) object Main { def main(args: Array[String]): Unit = { val person = Person("", 150) val validatorFactory = Validation.buildDefaultValidatorFactory() val validator: Validator = validatorFactory.getValidator val violations: Set[ConstraintViolation[Person]] = validator.validate(person) if (violations.nonEmpty) { for (violation <- violations) { println(violation.getMessage) } } else { println("Person is valid.") } } } In this example code, we first define a Person class.Next, in the main method, we created a Person object and verified it with the Bean Validation framework. Obtain the verification device by calling the factory instance by calling the `value.builddefaultValidatorFactory () method, and then obtain the verification device through the` valueFactory.GetValidator` method. Finally, we use the method of the Person object to use the method of `validator.validate (Person).If the Person object does not meet the constraints, a set of Constraintvilation objects return.We can traverse these objects and output the corresponding verification error messages.If the Person object is effective, the output "Person is Valid.". 4. Use Bean Validation in practical applications The example code is just a simple entry demonstration of the Bean Validation framework. In practical applications, we can define custom annotations and constraints according to our own needs, and apply it to various attributes or methods. For example, we can create a custom annotation `@Validemail` to verify the effectiveness of the email address: scala import javax.validation.constraints.{Email, Pattern} @Email @Pattern(regexp = ".*@example\\.com") class ValidEmail Then, we can apply this annotation to the email attribute in the Person class: scala case class Person(name: String, age: Int, @ValidEmail email: String) In this way, we can use the Bean Validation framework to easily verify the attributes in the data model and ensure the constraints that we expect. in conclusion: In the Java library, Bean Validation is a very useful tool to verify the effectiveness of the JavaBeans property.By using it, developers can simplify verification logic to ensure that objects in the application meet specific constraints.In SCALA, we can easily use the Bean Validation framework and customize the verification rules as needed.This article provides an example code to demonstrate the basic usage of the Bean Validation framework in practical applications.