Comparison of commentary scanning in the scannotation framework and the Java library
Combate scanning scanning scanning in the scannotation framework and the Java library
Introduction:
With the development of the Java language, annotations have become one of the important features in code development.The annotation provides a mechanism that adds metadata information to the code, which can be accessed and processed during compilation and runtime.In order to effectively use annotations, developers need to scan and analyze the annotations in the code.This article will compare the scanning function of the Scannotation framework and the Java class library and share their characteristics and usage.
1. Scannotation framework
Scannotation is an open source Java framework that is used to quickly scan the annotations in class files and resource files.It provides tool categories and APIs for scanning and parsing annotations, enabling developers to use and handle annotations easier.
Features of scannotation framework:
1. Quick scanning: Scannotation can quickly and accurately scan the annotations in class files and resource files by using low -level bytecode scanning technology.
2. Flexible API: Scannotation provides rich APIs, so that developers can customize the rules and strategies of commentary scanning to meet different needs.
3. Multiple annotations type support: Scannotation supports scanning and analytical multiple annotations, including classification, method annotations, field annotations, etc.
4. Easy integration: Scannotation can be seamlessly integrated with other Java frameworks and tools, such as Spring, Hibernate, etc.
Example of the use of scannotation framework:
Below is a sample code that uses Scannotation framework scanning category:
import org.scannotation.ClasspathUrlFinder;
import org.scannotation.WarUrlFinder;
import org.scannotation.archiveiterator.FilteredArchiveIterator;
import org.scannotation.archiveiterator.JarIterator;
import org.scannotation.archiveiterator.StreamIterator;
import org.scannotation.archiveiterator.WebIterator;
import org.scannotation.scanner.ClasspathScanner;
public class AnnotationScanner {
public static void main(String[] args) {
// Comment on scanning paths
ClasspathScanner scanner = new ClasspathScanner();
scanner.scan(ClasspathUrlFinder.findClassPaths());
scanner.getAnnotations().forEach(System.out::println);
// Scan the annotation in web applications
WebIterator webIterator = new WebIterator(WarUrlFinder.findWebInfClassesPath());
FilteredArchiveIterator filteredArchiveIterator = new FilteredArchiveIterator(
webIterator,
New String [] {"ORG/MyProject/EXClude/**"} // Remove the class under the specified package
);
scanner.scan(filteredArchiveIterator);
scanner.getAnnotations().forEach(System.out::println);
// Scan the annotation in the jar package
JarIterator jarIterator = new JarIterator("/path/to/myjar.jar");
StreamIterator streamIterator = new StreamIterator(jarIterator);
scanner.scan(streamIterator);
scanner.getAnnotations().forEach(System.out::println);
}
}
2. Comment scanning in the Java class library
Starting from Java 6, some APIs are provided in the Java library to scan and analyze annotations in scanning and analytical files.These APIs are included in the Java reflection mechanism, which can obtain metadata information that can be obtained through reflexes, including annotations.
Note scanning characteristics in the Java class library:
1. Standard API: Comment scanning in the Java class library is based on the Java standard reflection API, without additional dependencies.
2. Flexibility: Developers can use the rules and strategies of reflected API customized annotation scanning.
3. Jested scanning: Java reflective API supports nested scanning, which can scan different levels such as scanning class, methods, fields and other levels.
Example of comments scanning in Java Library:
Below is an example code that uses the Java reflective API scanning category:
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
public class AnnotationScanner {
public static void main(String[] args) throws ClassNotFoundException {
// Comment on scanning paths
Class<?> clazz = Class.forName("com.myproject.MyClass");
Annotation[] classAnnotations = clazz.getAnnotations();
for (Annotation annotation : classAnnotations) {
System.out.println(annotation);
}
// Method annotation in scanning classes
Method[] methods = clazz.getDeclaredMethods();
for (Method method : methods) {
Annotation[] methodAnnotations = method.getAnnotations();
for (Annotation annotation : methodAnnotations) {
System.out.println(annotation);
}
}
// Field annotations in scanning classes
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
Annotation[] fieldAnnotations = field.getAnnotations();
for (Annotation annotation : fieldAnnotations) {
System.out.println(annotation);
}
}
}
}
Summarize:
The scanning scanning scans in the Scannotation framework and the Java class library has their own characteristics and usage.The Scannotation framework provides efficient and flexible annotation scanning functions, which is suitable for scenarios that need to scan a large number of files and resource files.The annotations in the Java library are based on standard reflex APIs, which are suitable for simple annotation scanning requirements.Developers can choose the appropriate annotation scanning method to handle and analyze the annotations according to specific needs.
