In -depth analysis of Valdr Bean Validation framework principles and mechanisms in the Java class library

Valdr Bean Validation framework is a Java class library that is used to implement object verification and data verification in the application.It is developed based on the standard Bean Validation framework, which provides a simple and flexible way to verify the fields and properties in the Java object. The principles and mechanisms of Valdr Bean Validation are mainly involved in the following aspects: 1. Note: Valdr Bean Validation framework uses annotations to mark the field or attributes that need to be verified.Common annotations include@notnull,@notblank,@siZe, etc. These annotations define the rules and conditions of verification. 2. The verification device: A series of built -in verifications are provided in the framework to verify different types of fields or properties.The verification device will be verified according to the rules defined in the annotation and returns the verification results. 3. Verification process: Verification process is the core part of the framework.When calling the verification method in the application, the framework will be verified based on the annotation and the verification.The verification process includes the following steps: -Check whether the field or attribute is marked as a required verification.If there is no mark, skip the verification. -Adamed according to annotations and verifications.The verification device will verify the field or attribute according to the rules defined in the annotation. -If the verification failure, throw an abnormal or return error message. 4. Error treatment: The framework provides an error treatment mechanism, which can be processed to the failure of the verification.You can define the processing strategy by configuring the error processor, such as throwing abnormalities and returning error messages. 5. Configuration: When using Valdr Bean Validation framework, you need to perform some configuration.Configuration mainly includes definition of verification rules, configuration error processors, etc. The following is an example code that shows how to use Valdr Bean Validation framework for object verification: public class User { @Notnull (Message = "Username cannot be empty") @Size (min = 3, max = 20, message = "Username length must be between 3 and 20") private String username; @NotBlank (Message = "Password cannot be empty") private String password; // omit the getter and setter method } public class UserService { public void createUser(User user) { // Call the verification method for object verification ValidatorFactory factory = Validation.buildDefaultValidatorFactory(); Validator validator = factory.getValidator(); Set<ConstraintViolation<User>> violations = validator.validate(user); // Check the verification results if (!violations.isEmpty()) { // Process verification failure, such as printing error information for (ConstraintViolation<User> violation : violations) { System.out.println(violation.getMessage()); } } else { // Successful verification and follow -up operation // ... } } } In the above code, the User class uses annotations provided by the Valdr Bean Validation framework to define the verification rules.The Createuser method in the UserService class uses Validator to verify the user object and processes accordingly according to the verification results. By understanding the principles and mechanisms of Valdr Bean Validation framework, we can better apply the framework to realize the function of object verification and data verification.And according to specific needs, corresponding configuration and customization can be performed to improve the reliability and security of the application.