Java Class Library Validation :: API framework technical summary
Java class library Validation :: API framework technical principle summary
introduction:
Java Library Validation :: API framework is a powerful tool for verifying the effectiveness of data. It has flexibility and scalability.This article will outline the technical principles of this framework and provide some Java code examples to illustrate its usage.
1. Validation :: API Introduction
Java Library Validation :: API is a framework for validating data validity provided by Java.It contains a set of annotations, interfaces, and classes that can be used to verify whether the fields and methods in the data model are in line with pre -defined rules.This can ensure the integrity and correctness of the data, avoiding abnormal or errors when the program is running.
2. Validation :: API working principle
1. Note
Validation :: API's core is a set of interfaces for annotations. These interfaces define different types of verification rules.You can apply these annotations to fields or methods to define the constraints of data.
2. Verification device
Validation :: API provides a set of built -in validators to perform verification operations.The implementation classes of these verifications can check the effectiveness of the data according to the rules defined in the annotation.
3. constraint context
Before verification, a constraints need to be created.This object is used to store the verification device and verification results.You can set the authentication of the configuration options to restrict the processing method used in the context, and the processing method when verifying the failure.
4. Verification process
When the verification device executes the verification operation, it checks whether the rules defined by the annotation are met.If it is not satisfied, the verification device will record the failed information in the constraint context.Otherwise, the validator will continue to check the next verification rules.
5. Verification results
After completing the verification, the verification results can be obtained from the constraints.Verification results include statistical information of verification operations, such as verifying the number of data passed and the number of data failed.You can judge the effectiveness of the data based on this information and take corresponding operations as needed.
Third, sample code
The following is a simple example of using Validation :: API framework:
import javax.validation.constraints.*;
public class Person {
@NotNull
private String name;
@Min(18)
private int age;
@Email
private String email;
// Getter and Setter methods
public static void main(String[] args) {
Person person = new Person();
person.setName("John");
person.setAge(25);
person.setEmail("john@example.com");
// Verify the effectiveness of data
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
Validator validator = factory.getValidator();
Set<ConstraintViolation<Person>> violations = validator.validate(person);
// Judgment verification results
if (violations.isEmpty()) {
System.out.println ("Person object verification pass");
} else {
for (ConstraintViolation<Person> violation : violations) {
System.out.println(violation.getMessage());
}
}
}
}
In the above examples, the field names, Age, and Email in the Person class use@notnull,@min, and @email annotations, respectively.In the main method, we first used the static method of the Validation class to create a verification factory factory.Then, a verification device instance was obtained through the verification device factory.Next, we used the verification device to perform data verification operations on the Person object and obtained the verification results.Finally, the corresponding information is output according to the verification results.
in conclusion:
This article outlines the technical principles of the Java class library value :: API framework, and provides a simple example code to illustrate its usage.By using Validation :: API, you can easily verify the data to ensure its effectiveness and correctness, thereby improving the robustness and reliability of the program.
