Valdr Bean Validation framework in the Java class library analysis
Valdr Bean Validation framework is a verification framework widely used in the Java library.Based on the JSR 303 standard, it verifies Java objects through annotations to improve the reliability and robustness of the code.This article will analyze the application case of Valdr Bean Validation framework in the Java library and explain its related programming code and configuration.
In an enterprise -level Java application, data verification is a very important part.Data verification can ensure the correctness and consistency of the data, and avoid data abnormality and errors.The Valdr Bean Validation framework provides a simple and flexible method to verify the data in the Java object.
The following is an example case, showing how to use the Valdr Bean Validation framework in the Java class library for data verification.
1. First, we need to add the dependency item of the Valdr Bean Validation framework to the project dependency management.You can use Maven to manage the dependence of the project.Add the following dependencies to the pom.xml file:
<dependency>
<groupId>org.valdr</groupId>
<artifactId>valdr-bean-validation</artifactId>
<version>1.2.0</version>
</dependency>
2. Create a Java class that contains data fields that need to be verified.For example, we create a class called `user``, including names and age fields, and use the annotation of the Valdr Bean Validation framework on the field for verification.
public class User {
@Notnull (Message = "Name cannot be empty")
private String name;
@Min (Value = 18, Message = "Age must be greater than or equal to 18 years"))
private int age;
// omit the creation function and getter/setter method
}
In the above example, the annotation of the Valdr Bean Validation framework `@notnull`` and` `@min`` to verify` name`` and `` Age`` and fields.If the field verification fails, the framework will return the corresponding error message.
3. Create a verification device class to perform data verification.We create a class named `` value ``, to achieve verification logic by calling the API of the Valdr Bean Validation framework.
import org.valdr.Validator;
import org.valdr.beans.ValidationResult;
public class UserValidator {
public ValidationResult validate(User user) {
Validator validator = new Validator();
return validator.validate(user);
}
}
In the above examples, we use the `value` "class of the Valdr Bean Validation framework to perform the verification operation.By calling the `` value`` method, and passing the subject to verify as a parameter, we can get a `` valueResult`` object.
4. Finally, call the verification class in the application to perform the data verification operation.
public class App {
public static void main(String[] args) {
User user = new User();
user.setName(null);
user.setAge(15);
UserValidator validator = new UserValidator();
ValidationResult result = validator.validate(user);
if (result.hasViolations()) {
System.out.println ("Data verification failed:");
for (String message : result.getMessages()) {
System.out.println(message);
}
} else {
System.out.println ("Data verification is successful!");
}
}
}
In the above example, we created a class called `` APP``, which created an `user`` object in its` main`` method and set some invalid data.Then, we instinctively `userValidator``, and call the` `value` `method to perform data verification.Finally, according to the verification results, we print the corresponding messages.
Through the above examples, we can see the application cases of the Valdr Bean Validation framework in the Java library.The framework provides a simple and flexible verification solution that can help developers easily implement data verification function in the Java class library and improve code quality and reliability.
It should be noted that the above example is only a simple application case based on the Valdr Bean Validation framework. In actual use, more complicated verification logic and more configuration may be required.Developers can further study and practice according to specific needs.
