The technical principle of verification framework framework in the application of the Java class library
The verification framework is one of the frameworks that play a key role in software development.It provides developers with a convenient method to verify the correctness of the code and can reduce the error rate in the development process.In the Java class library, there are many verification frameworks to choose from, such as Hibernate Validator, Spring Validation, etc., which all provide the application of the technical principles of the verification framework in the Java library.
The technical principles of the verification framework mainly include annotations, reflexes and verifications.Developers can use annotations to mark the fields or methods that need to be verified, and define the verification rules.The verification framework can obtain the marked fields or methods through reflection technology, and verify according to the defined rules.Finally, the verification device performs specific verification operations on the field or method and returns the verification results.
The following uses Hibernate Validator as an example to discuss the application of the verification framework in the Java library.
First, developers need to introduce the dependence of Hibernate Validator.In the Maven project, you can add the following dependencies to the pom.xml file:
<dependency>
<groupId>org.hibernate.validator</groupId>
<artifactId>hibernate-validator</artifactId>
<version>7.0.1.Final</version>
</dependency>
Next, define verification rules by adding annotations to the target class.For example, in a user class, we can use @Notblank annotations to mark the user name field:
public class User {
@NotBlank (Message = "Username cannot be empty")
private String username;
// omit other fields and methods
}
In the above code, the@notblank annotation indicates that the field cannot be empty, and can define the error message when verification is not approved.
Finally, the verification method provided by the verification framework is called to verify the target object.The following is a simple verification example:
import org.hibernate.validator.HibernateValidator;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import javax.validation.constraints.NotBlank;
import java.util.Set;
public class Main {
public static void main(String[] args) {
ValidatorFactory factory = Validation.byProvider(HibernateValidator.class)
.configure()
.failFast(true)
.buildValidatorFactory();
Validator validator = factory.getValidator();
User user = new User();
user.setUsername("");
Set<ConstraintViolation<User>> violations = validator.validate(user);
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getMessage());
}
}
}
In the above code, a validatorFactory instance is first created, and the Hibernate Validator is specified by the configuration method.Then obtain a validator instance through the getValidator () method.
Then create a user object and set a empty string as the username.Finally, the user object is verified by calling the value method and the collection of verification results.If the verification is not approved, the error message can be output through the collection.
In summary, the application of the technical principle of the verification framework in the Java library can be implemented through the combination of annotations, reflexes and verifications.By introducing the dependencies of the verification framework, using the annotation definition verification rules, and obtaining the target object and verifying through the reflex technology, the verification results are finally obtained.The above is an implementation method using Hibernate Validator as an example.Developers can choose the appropriate verification framework according to the requirements of the project, and use and customize according to the specific business scenarios.
