The new features and updates of the JSR 303 verification constraint framework
The new features and updates of JSR 303 verification constraint framework
Introduction:
JSR 303 is an important specification for the Java community to provide standard specifications for JavaBean verification.It defines a set of annotations to verify and restraint the attributes of JavaBean in application development.These verifications and constraints can ensure the accuracy and integrity of the data, thereby improving the stability and security of the system.This article will introduce the new features and updates of the JSR 303 verification constraint framework to help developers better understand and use this specification.
1. New verification annotation
The latest version of JSR 303 has added some new verification annotations to meet more business needs.Here are some commonly used new verification annotations:
1. @Notempty: Check whether the string, collection or array is empty;
2. @NotBlank: Check whether the string is not empty, and the length is greater than 0, remove the blank characters before and after;
3. @email: Check whether the string conforms to the email format;
4. @pattern: Check whether the string matches the specified regular expression.
These new verification annotations provide more verification options for developers, which can more accurately define and control the effectiveness of data.
2. Update verification annotation
In addition to the new verification annotation, the JSR 303 has also updated and improved the original verification annotation.Here are some updates instructions for verification annotations:
1. @size: This annotation can be used for string, collection and array.If you are used to a string, you can specify the minimum length and maximum length limit.If it is applied to a collection or array, you can specify the limit of the minimum element and the maximum number of elements;
2. @Range: This annotation can be used for the attributes of the digital type, specify the limit of the value range, including the minimum value and maximum value;
3. @valid: This annotation is used for grade joint verification, that is, the verification operation of the associated object is performed;
4. @Notnull: This annotation is used to check whether the attribute is null.
These updated verification annotations enable developers to verify data more flexibly and support more types of attributes.
Third, sample code
Below is an example code that uses JSR 303 to verify the constraint framework.Suppose we have a user -class user, which contains the two attributes of the username and age, and we hope to verify these two attributes.
public class User {
@Notempty (Message = "Username cannot be empty")
private String username;
@Min (Value = 18, Message = "Age must be greater than or equal to 18 years"))
private int age;
// omit the getter and setter method
}
In the above example, we used @Notempty annotations to verify non -empty user names and specified error messages.The minimum verification of age is used to use @MIN annotations, and the age must be greater than or equal to 18 years.
Then, we can use the verification framework where the user enters is required to verify the operation.
public class Main {
public static void main(String[] args) {
User user = new User();
user.setUsername("");
user.setAge(16);
ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
Validator validator = validatorFactory.getValidator();
Set<ConstraintViolation<User>> violations = validator.validate(user);
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getMessage());
}
}
}
In the above sample code, we created a verification factory, and then obtained the verification instance by verifying the factory.We then call the value method to verify the User object and obtain the verification results set.Finally, we traversed the error message of the verification results set and the output verification failed.
Summarize:
The JSR 303 verification constraint framework provides powerful data verification and constraints, which can help us ensure the accuracy and integrity of the data.Through the new features and updates introduced herein, developers can more flexibly verify data and can be customized according to business needs.It is hoped that this article will help developers understand and use the JSR 303 verification constraint framework.
