Valdr Bean Validation Framework Optimized Java Library Development Practical Skills

Bean Validation is a Java specification that is used to verify and verify the attributes of objects.It provides a simple and scalable way by using annotations, APIs, and verifications to ensure that the attribute of the object meets specific conditions.This article will introduce some practical skills to optimize the development of the Java library, and how to use the Bean Validation framework during the development process. 1. Introduce Bean Validation dependencies First, we need to introduce the dependencies of Bean Validation in the project.Usually, we can use Maven or Gradle to configure the dependence of the project.The following is an example of using Maven configuration dependency relationship: <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>7.0.1.Final</version> </dependency> 2. Create a model class Next, we can create a model class that needs to be verified.Suppose we have a User class that contains user names and age attributes.We can use the Bean Validation annotation to define the verification rules.The following is an example: public class User { @Notempty (Message = "Username cannot be empty") private String username; @Min (Value = 18, Message = "Age must be greater than or equal to 18 years")) private int age; // omit other attributes and methods } In the above examples, the annotation of `@notempty` We ensure that the user name attribute is not empty, and it can be customized by the` Message` attribute to verify the error message displayed when failed.Through `@min`, we ensure that the value of the age attribute must be greater than or equal to 18. 3. Verify model object Once we create a model class, we can verify the attributes of the model object where we need.The following is an example: public class Main { public static void main(String[] args) { User user = new User(); user.setUsername(""); user.setAge(17); 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 up an empty user name and a age of less than 18.Then, we use the `buildDefaultValidatorFactory` method to create a` validatorFactory` method to create an instance of the `Vetvalidator` method.Finally, we use the `Validate` method to verify the user object, and obtain and print the error message of the failure of the failure by traversing the` Constraintviolation "object set. Through the above steps, we can use the Bean Validation framework to optimize the development of the Java library.By using the Bean Validation annotation, we can easily check the model object without writing a large number of repeated verification logic.This can improve the maintenance and readability of the code, avoid writing lengthy verification logic, and ensure that the attributes of the model object meet the specific conditions.