Java -class library verification framework (Working Principles of the Validation Framework in Java Class Libraries))
The working principle of the Java library verification framework
introduction:
In software development, data verification is an important task to ensure the accuracy and integrity of data.In order to simplify the process of data verification of developers, Java provides many types of library verification frameworks.This article will introduce the working principle of the Java class library verification framework, and provide some Java code examples to help readers better understand its realization process.
1. What is the Java class library verification framework?
The Java -class library verification framework is a tool set for checking the effectiveness of data.By using the verification framework, developers can define rules to verify data, thereby reducing the risk of errors or abnormal data.The verification framework provides a simple and powerful method that allows developers to intuitively verify data and improve the maintenance and readability of code.
Second, common Java library verification framework
In Java, there are many popular library verification frameworks that can be used, including but not limited to the following:
1. Hibernate Validator: It is an annotated verification framework that is currently widely used in Java Ee and Spring applications.
2. Apache Commons Validator: It is an open source framework for verifying the input data, which provides a set of verification rules and verifications.
3. Bean Validation API: It is part of the Java Ee and provides an annotation -based verification mechanism.
3. The working principle of the Java class library verification framework
The working principle of the Java class library verification framework can be simply divided into the following steps:
1. Define the verification rules:
Developers use the annotations or configuration file definition verification rules provided by the class library verification framework.These rules can define positions such as physical class, method parameters, and method return values.
2. Data verification:
When the data is submitted to the verification framework, the verification framework will verify the data according to the predetermined rules.The verification framework will check the effectiveness of the data and return the corresponding verification results according to the verification rules.
3. Processing verification results:
Developers can handle them accordingly according to the verification results.For example, if data verification fails, you can return error information to users, or perform other necessary operations.
The following is an example of using the Hibernate Validator verification framework. It demonstrates how to define the verification rules and process the verification results:
Step 1: Introduce dependency library
In the Maven project, add the following dependencies to the pom.xml file:
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>2.0.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate.validator</groupId>
<artifactId>hibernate-validator</artifactId>
<version>6.0.17.Final</version>
</dependency>
Step 2: Define the physical class
import javax.validation.constraints.NotEmpty;
public class User {
@Notempty (Message = "Username cannot be empty")
private String username;
@Notempty (MESSAGE = "Password cannot be empty")
private String password;
// omit the getter and setter method
}
STEP 3: Perform data verification
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import javax.validation.ConstraintViolation;
public class Main {
public static void main(String[] args) {
User user = new User();
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
Validator validator = factory.getValidator();
Set<ConstraintViolation<User>> violations = validator.validate(user);
if (violations.size() > 0) {
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getMessage());
}
}
}
}
In the above examples, we define a User class and use @NoteMPTY annotations on Username and Password fields to specify the verification rules that cannot be empty.Then, we use the Hibernate Validator API to create a value instance and verify the User object.If the verification fails, we will print the corresponding error information.
in conclusion:
The Java library verification framework enables developers to easily verify data and provide a powerful and flexible way to ensure the effectiveness and integrity of the data.This article introduces the working principle of the Java library verification framework, and provides a process of demonstrating the verification process using the Hibernate Validator.It is hoped that readers can better understand and apply the JAVA library verification framework through this article.
