Decrypted the Validation :: API framework technical principles in the Java class library

Decrypted Validation :: API framework technical principle in the Java class library introduction: Data verification is a very important link when developing Java applications.Data verification can ensure that the data entered by the user conforms to the expected format, scope and rules, thereby enhancing the security and reliability of the application.In order to simplify and unified data verification, the Java class library provides validation :: API framework. This article will decrypt the technical principles of Validation :: API framework, and provide the corresponding Java code example to help readers understand the framework in depth. 1. Validation :: API framework Introduction: Validation :: API is a set of data verification API defined in the Javaee 6 specification.It provides a set of interfaces and classes defining verification rules and constraints, as well as the corresponding verification device implementation.Through Validation :: API, developers can easily define and execute verification rules in the application to ensure the legitimacy of the input data. Second, commonly use value :: API Note: Validation :: API framework provides some commonly used annotations to define different types of verification rules.Here are some of these commonly used annotations and functions: 1. @Notnull: This annotation is used to verify fields or parameters cannot be NULL. Example code: @NotNull private String username; 2. @Notempty: This annotation is used to verify the string field or the collection field cannot be null or empty. Example code: @NotEmpty private String firstName; @NotEmpty private List<String> emails; 3. @min and @Max: These two annotations are used to verify the minimum and maximum values of the digital fields. Example code: @Min(0) private int age; @Max(100) private int score; 4. @Pattern: This annotation is used to verify whether the format of the field meets the specified regular expression. Example code: @Pattern(regexp = "[A-Za-z0-9]+") private String password; The above is only part of the annotations provided by Validation ::pi. Developers can choose appropriate annotations according to actual needs to define verification rules. 3. Validation :: API verification device: In addition to the annotation, Validation :: API also provides some built -in verifications to perform verification rules.For example, developers can use the verification device to implement the class to verify whether the rules of the annotation definition are met. Here are some commonly used verifications provided by Validation :: API: 1. Validator: This validator interface is the core interface in Validation :: API, defining the execution method of verification rules. Example code: Validator validator = Validation.buildDefaultValidatorFactory().getValidator(); Set<ConstraintViolation<User>> violations = validator.validate(user); 2. ConstraintVilation: This class means verification of violations and can obtain the field name, error information, etc. that are not passed. Example code: for (ConstraintViolation<User> violation : violations) { System.out.println(violation.getPropertyPath() + ": " + violation.getMessage()); } By using the verification device provided by Validation :: API, developers can perform verification rules at runtime and obtain verification results. in conclusion: This article decrypts the technical principles of Validation :: API framework in the Java class library.Through Validation :: API, developers can standardize and simplify the process of data verification to increase the security and reliability of the application. We introduced the basic concepts of Validation :: API, commonly used annotations and verifications, and provide the corresponding Java code example. It is hoped that this article can help readers understand Validation :: API framework, and can apply these knowledge in actual development to improve the quality and maintenance of the project.