The Kaml framework in the Java Library (Guide to use the kaml framework in Java Class Libraries)

Guidance of the Kaml framework in the Java class library Overview: Kaml (KOTLIN Annotion Markup Language) is an open source framework for generating annotation processors in the Java class library.It provides a simple and flexible way to write the annotation processor and be able to generate Java code for code generation and resource processing tasks during compilation.This article will introduce how to use the KAML framework in the Java library and give the corresponding Java code example. Use the KAML framework in the Java library: The following is the steps to generate the annotation processor in the Java library with the KAML framework: Step 1: Add dependencies First, add KAML framework dependencies to the construction script of your Java library project.You can get the corresponding dependencies from the Maven central warehouse or Gradle plug -in. Maven: <dependency> <groupId>com.github.tomxiong5</groupId> <artifactId>kaml-processor</artifactId> <version>1.0.0</version> <scope>provided</scope> </dependency> Gradle: groovy implementation 'com.github.tomxiong5:kaml-processor:1.0.0' annotationProcessor 'com.github.tomxiong5:kaml-processor:1.0.0' Step 2: Create annotations Next, you need to create custom annotations in your Java library.The Kaml framework will generate the corresponding code according to the annotation of your definition. import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Retention(RetentionPolicy.SOURCE) @Target(ElementType.TYPE) public @interface MyAnnotation { String value(); } Step 3: Write the annotation processor You need to write a comment processor class.The annotation processor will process the corresponding code according to the annotation defined by your definition. import com.github.tomxiong5.kaml.annotation.GenerateCode; import com.squareup.javapoet.JavaFile; import com.squareup.javapoet.MethodSpec; import com.squareup.javapoet.TypeSpec; import javax.annotation.processing.*; import javax.lang.model.SourceVersion; import javax.lang.model.element.Element; import javax.lang.model.element.TypeElement; import javax.lang.model.util.Elements; import java.io.IOException; import java.util.HashSet; import java.util.Set; @SupportedAnnotationTypes("com.example.MyAnnotation") @SupportedSourceVersion(SourceVersion.RELEASE_8) public class MyAnnotationProcessor extends AbstractProcessor { private Filer filer; private Messager messager; private Elements elementUtils; @Override public synchronized void init(ProcessingEnvironment processingEnv) { super.init(processingEnv); filer = processingEnv.getFiler(); messager = processingEnv.getMessager(); elementUtils = processingEnv.getElementUtils(); } @Override public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { for (Element element : roundEnv.getElementsAnnotatedWith(MyAnnotation.class)) { GenerateCode generateCode = element.getAnnotation(GenerateCode.class); String value = generateCode.value(); MethodSpec constructor = MethodSpec.constructorBuilder() .addModifiers(Modifier.PUBLIC) .addParameter(String.class, "value") .addStatement("this.value = value") .build(); TypeSpec classSpec = TypeSpec.classBuilder("GeneratedClass") .addModifiers(Modifier.PUBLIC, Modifier.FINAL) .addField(String.class, "value", Modifier.PRIVATE, Modifier.FINAL) .addMethod(constructor) .build(); try { JavaFile.builder("com.example", classSpec) .build() .writeTo(filer); } catch (IOException e) { e.printStackTrace(); } } return true; } } Step 4: Register an annotation processor Finally, you need to register your annotation processor in the `Meta-INF/Services/Javax.annotation.Processing.Processor` file. Create the `meta-inf/services/javax.annotation.processor` file in the` com.example` directory, and add the name of your annotation processor class to the file. The content of the example is as follows: com.example.MyAnnotationProcessor Java code example explanation: The above Java code example demonstrates how to use the KAML framework to generate an annotation processor in the Java library.The dependencies of the KAML framework are added to Step 1, and a custom annotation `@myannotation` is created in Step 2.In the step 3, a comment processor `myannotationProcessor` is used to process the`@myannotation `annotation and generate the corresponding Java code according to the annotation.Step 4 will be registered in the Java annotation processor service. Summarize: Using the Kaml framework can easily generate an annotation processor in the Java library.Through four simple steps, you can define your own annotation and generate the corresponding code.The KAML framework provides a flexible and concise way to handle annotations, and can generate code generation during compilation, making your project more efficient and convenient.Give full play to your creativity and use the KAML framework to create a better Java library!