Explore the technical principles of verifying the core framework in the Java class library
Explore the technical principles of verifying the core framework in the Java class library
The core framework in the Java library is a key technology that is used to verify and ensure the legality and integrity of data in the application.This framework provides a mechanism that verifies the input data by using various verification annotations, verifications, and error processing mechanisms.
The most commonly used verification core framework in the Java class library is the implementation of the JSR 303 Bean Validation specification. It provides a set of annotations for verifying the Java object and can achieve the verification function through simple configuration.
In this framework, verification annotations are one of the core elements of verification.Common authentication annotations are@notnull,@notblank,@min,@max, etc.These annotations can be used for fields, method parameters, and return values, and are used to define verification rules and limited conditions.For example,@notnull annotation is used to identify a field cannot be empty,@min notes to identify the minimum value of a field.
In addition to verification annotations, the framework also provides a verification device.The verification device is a set of verification rules and logic classes used to verify the annotation.Each verification annotation can be associated with one or more verifications for verification.For example,@notnull annotations can be associated with notnullValidator verification device to ensure that the value of the field is not empty.
When the application verifies a certain object, the verification framework will verify the field of the object according to the annotation of the object and the related verification device.If the verification fails, the verification framework will generate corresponding verification errors.These verification errors can include the field information of error messages, errors, and verification failed.
The following is a simple example. It demonstrates how to use the verification core framework to verify a user object:
public class User {
@Notnull (Message = "Username cannot be empty")
private String username;
@NotBlank (Message = "Password cannot be empty")
@Size (min = 6, max = 20, message = "Password length must be between 6 and 20 characters")
private String password;
// omit other fields and methods
// Getters and Setters
}
public class Main {
public static void main(String[] args) {
User user = new User();
user.setUsername("");
user.setPassword("12345");
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 code, we define a User class, which contains two fields, which are verified with @Notnull and @Notblank annotations.We then verify the USER object using the verification core framework.If the verification fails, we will print the corresponding error messages.
All in all, by verifying the core framework, the Java class library provides a powerful and flexible mechanism to verify and ensure the legitimacy and completeness of data in the application.By using verification annotations, verification, and error processing mechanisms, we can easily implement the data verification function.This is very important for ensuring the quality and security of the data input.
