ObjectOS :: Auto :: Annitations framework technical principles in the Java class library

ObjectOS :: Auto :: Annitations framework technical principles in the Java class library In Java programming, annotation is a metadata form that can embed special annotation information in the source code.Objectos :: auto :: Annotations is a framework in the Java class library, which aims to simplify the writing and generation of code and improve development efficiency.This article will explain in detail the technical principles of ObjectOS :: Auto :: Annotations framework, and provide relevant Java code examples. Objectos :: auto :: Annotations framework to achieve the function of automatically generating code by commentary.Developers can use the framework to define the annotation during the encoding process, and automatically generate the corresponding code based on these annotations.The following is the principle of ObjectOS :: auto :: Annotations framework: 1. Define the type of annotation First, developers need to define their own types of annotations.The annotation type uses the keywords of `@interface` to contain some member variables.These member variables can be used to receive the value provided by developers when using annotations. public @interface MyAnnotation { String value(); } 2. Write a processor Next, developers need to write annitation processor to analyze and process annotations.The processor is the class of `javax.annotion.processing.processor` interfaces to achieve processing logic by rewriting specific methods. public class MyAnnotationProcessor extends AbstractProcessor { @Override public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { // Treatment of annotation logic return true; } } 3. Configuration processor In order to allow the compiler to automatically call the processor during compilation, you need to create a file named `Javax.annotation.processing.processor` in the project's` Meta-INF/Services` directory, which contains the complete processor's completeLimited name. com.example.MyAnnotationProcessor 4. Construction project After completing the above steps, you can use the Java compilation tool (Javac) to compile code.The compiler will automatically scan the annotation in the source code and call the corresponding processor for processing.The processor can generate new code or complete other tasks according to the annotation in the source code. @MyAnnotation("Hello World!") public class MyClass { // ... } In the above code, `myannotation` has a string parameter.When compiling, the compiler will call the `myannotationProcessor` processor, and pass the information annotated to the` Myannotation` to the processor.The processor can generate new code or perform other operations based on this information. ObjectOS :: Auto :: Annotations framework achieves the function of automatically generating code through the combination of annotations and processors.Developers can define different annotations according to their own needs and write corresponding processors to complete the task of automation code generation.This method has greatly improved development efficiency and reducing repeated labor. In summary, ObjectOS :: Auto :: Annitations framework uses the mechanism of annotations and processors to extract the annotation information in the source code and processes it accordingly to achieve the function of automatic generating code. The above is the detailed explanation of the technical principles of ObjectOS :: Auto :: Annotations, and provides the corresponding Java code example.It is hoped that this article can help readers understand and use ObjectOS :: Auto :: Annotations framework.