Java class library Validation :: API framework technical principle interpretation
Java class library Validation :: API framework technical principle interpretation
Introduction:
Validation API is a framework in the Java class library for data verification and verification.This article will explain the technical principles of the Validation API framework and provide some Java code examples.
Technical principle interpretation:
Java Library Validation :: API framework is created to simplify data verification and verification.It provides a set of basic interfaces and tools that allows developers to easily verify the input data.
First, we need to introduce the dependencies of the Validation API framework in our Java project.It can be implemented by adding the following configuration in the pom.xml file of the project:
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>2.0.1.Final</version>
</dependency>
Next, we need to create a Java class for the target object to be verified.Suppose we have a class called User. It has several fields that need to be verified, as shown below:
public class User {
@NotNull
private String name;
@Email
private String email;
@Size(min = 6, max = 12)
private String password;
// getters and setters
}
In the above example, we use the annotations provided by three Validation APIs to verify the User class field.@Notnull Note to ensure that the 'name' field is not empty,@email ensures that the 'email' field conforms to the format of email,@siZe (min = 6, max = 12) ensures that the length of the 'password' field is from 6 to 12 characters.between.
Next, we need to perform verification in the code.We can use Validator provided by the Validation API to perform verification operations.The following is a simple example:
public class Main {
public static void main(String[] args) {
User user = new User();
user.setName("John Doe");
user.setEmail("john.doe@example.com");
user.setPassword("password123");
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
Validator validator = factory.getValidator();
Set<ConstraintViolation<User>> violations = validator.validate(user);
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getMessage());
}
}
}
In the above example, we first created a User object and set the values of some fields.Then, we obtained a validatorFactory object through the BUILDDEFAULTVALTRIDALIDIDIDATORFACTORY () method of the Validation class, and used it to create a Validator object.Next, we use the validator.validate () method to verify the user object and obtain a collection of verification results.Finally, we only need to traverse the collection of verification results to print the detailed information of the verification error.
Summarize:
Validation :: API framework is one of the important technologies for data verification and verification in the Java class library.By using annotations and verifications provided by Validation API, developers can easily verify the Java objects.This article provides the technical principles of the Validation API framework, and has some simple Java code example for reference.It is hoped that this article can help readers in -depth understanding of the Validation API framework.
