Introduction to Java Ee Validation framework
Introduction to Java Ee Validation framework
Java Ee Validation is a framework on the Java Enterprise Edition (Java EE) platform to verify data.It provides a convenient way to verify the input data of the application to ensure specific rules and constraints.
The Java Ee Validation framework is based on the Java Standard Annotations, which provides a set of annotations for defining verification rules and constraints.By applying these annotations to the JavaBean attributes, data verification can be performed in the application.
In Java Ee Validation, the key annotation is the annotation in the Javax.Validation.Constraints package.These annotations include:
1. @Notnull: Verification cannot be empty
2. @Notempty: The verification cannot be empty, and the length must be greater than 0
3. @size: The length of the verification attribute value is within the specified range
4. @pattern: Verify whether the attribute value matches the specified regular expression
5. @EMAIL: Verify whether the attribute value is an valid email address
6. @Min: Verify whether the attribute value is greater than or equal to the specified minimum value
7. @Max: Verify whether the attribute value is less than or equal to the specified maximum value
In addition to these basic verification annotations, Java Ee Validation also provides some other annotations and characteristics for customization and expansion verification rules.Can customize annotations, create custom verifications, and use combination annotations to define more complicated verification rules.
Below is a simple example of using Java Ee value:
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
public class User {
@NotNull
@Size(min = 1, max = 20)
private String username;
@NotNull
@Size(min = 6, max = 20)
private String password;
// omit other attributes and methods
}
In the above examples, the User class uses @Notnull and @size annotations to define the verification rules for username and password properties.The username attribute cannot be empty, and the length must be between 1 to 20; the Password attribute cannot be empty, and the length must be between 6 and 20.
You can use the Validator class of Java Ee Validation to perform data verification.The following is a verification example:
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
public class Main {
public static void main(String[] args) {
User user = new User();
user.setUsername(null);
user.setPassword("password");
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 example, we created a user object, but did not set the value of the username property.Then, we use the Validator verification device to verify the User object and obtain a collection of verification results.If there are verification errors, you can traverse the error set and obtain the error message.
The Java Ee Validation framework provides a simple and powerful way to verify the input data of the application.It can help developers reduce errors and vulnerabilities, and improve the stability and security of applications.
We recommend using Java Ee Validation to verify the user input data in the application to ensure the integrity and effectiveness of the data.It is an important tool on the Java EE platform, which is very helpful for building reliable and secure applications.
