Detailed explanation of technical principles of verification framework framework in Java Library
Detailed explanation of the technical principle of verification framework in the Java class library
Overview:
In actual development, data verification and processing are an important link.The Java library provides many verification framework technology to verify the data entered by the user to ensure the legality and effectiveness of the data.This article will introduce the verification framework technical principles in the Java class library in detail and provide the corresponding Java code example.
1. The role of the verification framework
The main role of the verification framework is to verify the data entered by the user, including verifications of data types, formats, lengths, scope, etc. to ensure that the data meets the expected rules.The verification framework can effectively reduce code redundancy, improve development efficiency and readability of code.
2. Common Java verification framework
1. Hibernate Validator: Hibernate Validator is a powerful and flexible verification framework that is compatible with Java Bean verification (JSR 380).Through annotations, APIs, or custom verifications, the attributes of the object can be easily verified.
2. Apache Commons Validator: Apache Commons Validator is a regular expression framework. It provides a series of verification rules and general -purpose verifications that can be verified by common data types.
3. Spring Validation: Spring Validation is a verification framework provided by the Spring framework. It is based on the Java Bean verification (JSR 380), and data verification is performed through annotations or API.
4. JUNIT: Junit is a Java unit testing framework that can also be used for data verification.You can verify the input and output of the method of test cases to meet the expectations.
Third, the principle and implementation of the verification framework
1. Note verification: The verification framework in the Java library is verified by annotations.Developers can define the verification rules of attributes by adding corresponding verification annotations to the attributes of the Java class.The verification framework will analyze the coding solution at runtime, and data verification is performed according to the rules of the annotation.
Example code:
public class User {
@NotNull
private String username;
@Size(min = 6, max = 12)
private String password;
// omit the getter and setter method
}
2. API verification: In addition to using annotations for verification, the verification framework also provides API to verify.Developers can define verification rules and implement verification logic by writing code.The verification framework will be verified based on code logic.
Example code:
public class UserValidator {
public static boolean validate(User user) {
if (user.getUsername() == null || user.getUsername().isEmpty()) {
return false;
}
if (user.getPassword() == null || user.getPassword().length() < 6 || user.getPassword().length() > 12) {
return false;
}
return true;
}
}
3. Custom verification device: The verification framework also supports developers custom verification.Developers can meet specific verification needs by implementing the verification interface and realizing custom verification logic.
Example code:
public class CustomValidator implements ConstraintValidator<CustomValidation, String> {
@Override
public void initialize(CustomValidation constraintAnnotation) {
// Initialize operation
}
@Override
public boolean isValid(String value, ConstraintValidatorContext context) {
// Customized verification logic
// If you meet the verification rules, return to TRUE; otherwise, return false
}
}
4. How to use the verification framework
1. Data verification: When using the verification framework, you need to pass the data to be verified into the verification device for verification.The verification framework will determine whether the data is legal according to the defined verification rules and return the verification results.
Example code:
User user = new User();
user.setUsername("admin");
user.setPassword("123456");
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
javax.validation.Validator validator = factory.getValidator();
Set<ConstraintViolation<User>> violations = validator.validate(user);
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getMessage());
}
2. Abnormal processing: During the data verification process, if the data does not meet the verification rules, the verification framework will throw an abnormality.Developers can handle abnormalities in the verification process through an abnormal processing mechanism and perform corresponding errors.
Example code:
try {
// Data verification code
} catch (ConstraintViolationException e) {
Set<ConstraintViolation<?>> violations = e.getConstraintViolations();
for (ConstraintViolation<?> violation : violations) {
System.out.println(violation.getMessage());
}
}
Summarize:
The verification framework in the Java library realizes the data verification function through annotations, APIs, and custom verifications.Developers can choose the appropriate verification framework according to actual needs to improve the reliability and maintenance of code.By learning the method and principle of the use of verification framework, you can better apply verification framework technology and improve development efficiency.
