Use the Java Ee Validation framework in the Java library
The Java EE Validation framework is part of Java. During the development process, you can use the framework to verify and check the input data.This framework provides a set of annotations that can use these annotations to define the verification rules to ensure the correctness of the input data.In this article, we will discuss how to use the Java Ee Validation framework in the Java library for data verification and provide some example code.
First, we need to add the Java Ee Validation framework to the project.In the Maven project, the following dependencies can be added to the pom.xml file:
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>2.0.1.Final</version>
</dependency>
After completing the dependencies, we can start using the Java Ee Validation framework.Suppose we have a User class that contains the basic information of some users, such as the username, age, and mailbox address.We want to verify this information to ensure that they meet our requirements.
The example code is as follows:
import javax.validation.constraints.*;
public class User {
@NotNull
@Size (min = 3, max = 20, message = "Username length must be between 3 and 20")
private String username;
@Min (Value = 18, Message = "Age must be greater than or equal to 18 years"))
private int age;
@Email (message = "Email address is incorrect")
private String email;
// omit the getter and setter method
}
In the above example code, we use some commonly used verification annotations.`@Notnull` to ensure that the field is not null;` `@` defines the range of the string length; `` MIN` ensures that the value is greater than or equal to the specified value;
It is very simple to use the Java EE Validation framework, just add appropriate annotations to the field to be verified.The verification process is usually performed in the service layer or control layer in the program. You can use the `value of` javax.validation.Validator` interface to perform verification.
The following is an example code that uses the Java Ee Validation framework to verify the USER class:
import javax.validation.*;
import java.util.Set;
public class Main {
public static void main(String[] args) {
User user = new User();
user.setUsername("abc");
user.setAge(16);
user.setEmail("abc");
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 code, we first created a User object and set some values that do not meet the verification rules.Then, we used the `Javax.Validation. Validation` class to create a validatorFactory object.By calling the `GetValidator` method, we obtained a validator object, which can be used to perform verification.
Finally, we use the `Validate` method to verify the user object and save the verification results in a set of sets.Finally, we traversed the set of sets to print the news of each verification failure.
In summary, the Java Ee Validation framework is a powerful tool that can help us easily verify and verify the data.By using verification annotations, we can quickly define the verification rules and use the verification input data provided by the framework.In this way, we can better ensure the data integrity and security of the system.I hope this article is helpful to you how to use the Java Ee Validation framework in the Java class library!
