When developing the Java library, in order to ensure the effectiveness and legitimacy of the input data, the application verification framework is very important.The verification framework can help developers easily realize the verification of data and provide friendly error prompt information.This article will introduce the best practice of the application verification framework in the Java class library and give some Java code examples.
1. Select the appropriate verification framework: When selecting the verification framework, the reliability, function richness and community support of the framework should be considered.The more popular Java verification frameworks are Hibernate Validator, Apache Commons Validator and Spring Validation.
2. Use annotations for verification: Commenting is a very useful mechanism in Java, which can provide metadata and verification information for code.By adding annotations to the attributes of the class, developers can easily define verification rules.For example, using the Hibernate Validator framework, you can add@notnull,@size, etc. to the attributes to define the non -air and length constraints of the attribute.
public class User {
@NotNull
@Size(min = 2, max = 20)
private String name;
// other properties and methods here
}
3. Create an appropriate verification device class: In some cases, the annotation may not meet complex verification needs.For example, the verification rules need to cross multiple attributes or the verification logic that needs to be customized.In this case, a verification device class can be created to achieve custom verification logic.The verification class can implement javax.validation.constraintValidator interface, and add custom annotations to the attributes that need to be verified.
public class AgeValidValidator implements ConstraintValidator<AgeValid, Integer> {
@Override
public void initialize(AgeValid constraintAnnotation) {
// Initialize operation
}
@Override
public boolean isValid(Integer age, ConstraintValidatorContext context) {
// A custom logic of customized authentication here
return age >= 18 && age <= 60;
}
// other methods here
}
4. Integrated verification framework to the class library: integrate the verification framework into the class library so that it can automatically perform the verification operation.You can use the following ways to implement verification:
public class UserValidator {
private Validator validator;
public UserValidator() {
ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
validator = validatorFactory.getValidator();
}
public List<String> validate(User user) {
Set<ConstraintViolation<User>> violations = validator.validate(user);
List<String> errors = new ArrayList<>();
for (ConstraintViolation<User> violation : violations) {
errors.add(violation.getMessage());
}
return errors;
}
}
5. Provide friendly error prompt information: When verifying failure, in order to provide users with meaningful error prompt information, the Message property can be defined in the verification annotation, and the error prompt information is returned when the verification fails.You can also use internationalization to support multi -language error prompt information.
public class User {
@Notnull (Message = "Username cannot be empty")
@Size (min = 2, max = 20, message = "User name length must be between 2 and 20")
private String name;
// other properties and methods here
}
In short, the application verification framework is one of the best practices to ensure the robustness and data effectiveness when developing the Java class library.By selecting the appropriate verification framework, using annotations for verification, creating appropriate verification classes, and providing friendly error prompt information, the verification work can be simple and efficient, and the ease of use and robustness of the class library can be enhanced.
