Construct a maintenance of Java class library: use the Fluent Validator framework to improve the quality of code
Construct a maintenance of Java class library: use the Fluent Validator framework to improve the quality of code
Introduction:
When developing the Java library, the requirements for code quality are particularly important.This article will introduce how to use the Fluent Validator framework to improve the code quality of the Java library, thereby building a maintainable class library.
What is the Fluent Validator framework:
Fluent Validator is an open source Java framework for data verification.It provides a smooth API that makes the code clearer and easy to read. At the same time, it provides rich verification rules to meet various verification needs.
Why use Fluent Validator framework:
1. Improve code readability: The API design of Fluent Validator is very simple and smooth. You can implement multiple verification rules by chain calling, making the code more clear and easy to read.
2. Improve code maintenance: Fluent Validator provides a variety of verification rules, which can easily complete various data verification requirements.By using Fluent Validator, the verification logic can be more concentrated, unified, and easy to maintain.
3. Reduce duplicate code: Fluent Validator provides rich built -in verification rules, and also supports custom verification rules, which can reduce duplicate verification logic in the code.
How to use Fluent Validator framework:
1. Introduce FLUENT VALIDATOR dependencies:
First, add the following dependencies to the pom.xml file of the project:
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-validator</artifactId>
<version>1.7</version>
</dependency>
2. Create verification rules:
First of all, we need to create a verification rule class.For example, we want to verify that the user name in a user object is not empty, and the length is between 5 and 20:
public class UserValidator implements Validator<User> {
@Override
public ValidationResult validate(User user) {
return new ValidationResult()
.adderrorif (StringUtils.isblank (User.getUsername ()), "Username cannot be empty")
.adderrorif (user.getUsername (). LENGTH () <5 || User.getUsername (). Length ()> 20, "The length of the user name must be between 5 and 20");
}
}
In the above code, we first created a `UserValidator` class to implement the` value <user> `interface.Then, we added two verification rules to the `value method to determine whether the user name is not empty and the length meets the requirements.If the verification is not approved, add an error message through the `adderrorif` method.
3. Use verification rules:
Where to verify, we can directly call the verification rules and obtain the verification results:
public class Main {
public static void main(String[] args) {
User user = new User();
user.setUsername("test");
UserValidator validator = new UserValidator();
ValidationResult result = validator.validate(user);
if (result.isValid()) {
// Verification Pass
} else {
// Verification does not pass, handle error information
List<String> errors = result.getErrors();
for (String error : errors) {
System.out.println(error);
}
}
}
}
In the above code, we created an object of `user` and set the username.Then, we instinctively `UserValidator" and called the `value method to verify.Finally, we judge whether the verification results pass. If it is not passed, the error message can be obtained through the `Geterrors` method.
Summarize:
By using the Fluent Validator framework, we can improve the code quality of the Java library.It can make the verification logic more concentrated and unified, and improve the readability and maintenance of code.It is hoped that this article can help readers build a maintainable Java library and improve the quality of code.
Please note: In order to demonstrate the use of Fluent Validator, this article uses Apache Commons Validator as verification dependencies.In actual projects, the implementation of other verification dependencies or custom verification rules can be selected according to the needs.
