使用AnnotationProcessor在特定包的java目录中编写Kotlin文件的方法如下:
apply plugin: 'kotlin-kapt'
dependencies {
kapt 'com.google.auto.factory:auto-factory:1.0-beta6'
implementation 'org.jetbrains.kotlin:kotlin-stdlib:1.5.31'
// 其他依赖...
}
KotlinGenerator
的Java类,并在需要生成Kotlin文件的包上添加@KotlinPackage
注解:import com.google.auto.factory.AutoFactory;
import com.google.auto.factory.Provided;
@AutoFactory
@KotlinPackage("com.example.kotlinpackage")
public class KotlinGenerator {
// ...
}
javax.annotation.processing.Processor
注解指定支持的注解类型,并重写process()
方法进行文件生成逻辑。例如,创建一个名为KotlinProcessor
的AnnotationProcessor类:import com.google.auto.service.AutoService;
import com.squareup.kotlinpoet.FileSpec;
import com.squareup.kotlinpoet.FunSpec;
import com.squareup.kotlinpoet.KotlinFile;
import com.squareup.kotlinpoet.TypeSpec;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.Processor;
import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;
@AutoService(Processor.class)
public class KotlinProcessor extends AbstractProcessor {
@Override
public Set<String> getSupportedAnnotationTypes() {
Set<String> annotations = new HashSet<>();
annotations.add(KotlinPackage.class.getCanonicalName());
return annotations;
}
@Override
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latestSupported();
}
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
for (TypeElement annotation : annotations) {
Set<? extends Element> annotatedElements = roundEnv.getElementsAnnotatedWith(annotation);
for (Element element : annotatedElements) {
if (element instanceof TypeElement) {
String packageName = element.getAnnotation(KotlinPackage.class).value();
// 生成Kotlin文件
generateKotlinFile(packageName);
}
}
}
return true;
}
private void generateKotlinFile(String packageName) {
TypeSpec.Builder classBuilder = TypeSpec.classBuilder("GeneratedKotlinClass")
.addFunction(FunSpec.builder("sayHello")
.addStatement("println(\"Hello, Kotlin!\")")
.build())
.addModifiers(KModifier.PUBLIC)
.build();
KotlinFile kotlinFile = KotlinFile.builder(packageName, classBuilder).build();
try {
FileSpec.Builder fileBuilder = FileSpec.builder(packageName, "GeneratedKotlinClass");
kotlinFile.writeTo(fileBuilder.build().javaFile(packageName));
fileBuilder.build().writeTo(processingEnv.getFiler());
} catch (IOException e) {
e.printStackTrace();
}
}
}
javac -processor your.annotation.processor.package.KotlinProcessor your/source/files/JavaFile.java
其中,your.annotation.processor.package
为自定义AnnotationProcessor类所在的包名,your/source/files/JavaFile.java
为包含特定包名注解的Java源文件路径。
package com.example.kotlinpackage
class GeneratedKotlinClass {
fun sayHello() {
println("Hello, Kotlin!")
}
}
至此,你已经学会如何使用AnnotationProcessor在特定包的java目录中编写Kotlin文件了。根据具体需求,你可以根据注解和自定义的逻辑生成各种类型的Kotlin文件。
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