Java 自定义批注处理器-使用批注检测方法
我正试图编写一个注释处理器来检测用@PrintMethod注释的方法。例如,在下面的测试类中,我想打印测试方法中的代码。有办法吗 从下面所述的AnnotationProcessor类中,我只能获得方法名称,但无法获得方法的详细信息 测试类Java 自定义批注处理器-使用批注检测方法,java,annotations,annotation-processing,Java,Annotations,Annotation Processing,我正试图编写一个注释处理器来检测用@PrintMethod注释的方法。例如,在下面的测试类中,我想打印测试方法中的代码。有办法吗 从下面所述的AnnotationProcessor类中,我只能获得方法名称,但无法获得方法的详细信息 测试类 public class test { public static void main(String[] args) { System.out.println("Args"); } @PrintMethod
public class test {
public static void main(String[] args) {
System.out.println("Args");
}
@PrintMethod
private boolean testMethod(String input) {
if(input!=null) {
return true;
}
return false;
}
}
public class AnnotationProcessor extends AbstractProcessor {
//......
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
//retrieve test Anntoation
Set<? extends Element> ann =roundEnv.getElementsAnnotatedWith(PrintMethod.class);
//Print the Method Name
for(Element e: ann) {
String msg="Element ee :"+ee.getSimpleName().toString();
processingEnv.getMessager().printMessage( javax.tools.Diagnostic.Kind.ERROR, msg, e);
}
}
}
注释处理器类
public class test {
public static void main(String[] args) {
System.out.println("Args");
}
@PrintMethod
private boolean testMethod(String input) {
if(input!=null) {
return true;
}
return false;
}
}
public class AnnotationProcessor extends AbstractProcessor {
//......
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
//retrieve test Anntoation
Set<? extends Element> ann =roundEnv.getElementsAnnotatedWith(PrintMethod.class);
//Print the Method Name
for(Element e: ann) {
String msg="Element ee :"+ee.getSimpleName().toString();
processingEnv.getMessager().printMessage( javax.tools.Diagnostic.Kind.ERROR, msg, e);
}
}
}
公共类AnnotationProcessor扩展了AbstractProcessor{
//......
@凌驾
public boolean process(Set我对此也很好奇,所以我决定尝试解决它。结果比我预期的要简单。您需要做的就是利用专有tools.jar库中的树
api。我在这里制作了一个快速注释处理器:
下面是它的要点:
@SupportedSourceVersion(SourceVersion.RELEASE_6)
@SupportedAnnotationTypes("org.printMethod.PrintMethod")
public class PrintMethodAnnotationProcessor extends AbstractProcessor {
private Trees trees;
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
trees = Trees.instance(processingEnv); //initialize the Trees api.
}
@Override
public boolean process(Set<? extends TypeElement> typeElements, RoundEnvironment roundEnvironment) {
MethodPrintScanner visitor = new MethodPrintScanner();
for (Element e : roundEnvironment.getElementsAnnotatedWith(PrintMethod.class)) {
TreePath tp = trees.getPath(e);
// visit the annotated methods
visitor.scan(tp, trees);
}
return true;
}
@Override
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latestSupported();
}
}
您可以看到,我们可以访问与给定的带注释元素关联的TreePath
。对于每个方法,我们只需println()
方法树,它提供了方法的内容
使用您的示例,以下是编译期间程序的输出:
@PrintMethod()
private boolean testMethod(String input) {
if (input != null) {
return true;
}
return false;
}
我对此也很好奇,所以我决定尝试解决它。结果比我预期的要简单。你所需要做的就是利用专有tools.jar库中的树
api。我已经按照以下思路制作了一个快速注释处理器:
下面是它的要点:
@SupportedSourceVersion(SourceVersion.RELEASE_6)
@SupportedAnnotationTypes("org.printMethod.PrintMethod")
public class PrintMethodAnnotationProcessor extends AbstractProcessor {
private Trees trees;
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
trees = Trees.instance(processingEnv); //initialize the Trees api.
}
@Override
public boolean process(Set<? extends TypeElement> typeElements, RoundEnvironment roundEnvironment) {
MethodPrintScanner visitor = new MethodPrintScanner();
for (Element e : roundEnvironment.getElementsAnnotatedWith(PrintMethod.class)) {
TreePath tp = trees.getPath(e);
// visit the annotated methods
visitor.scan(tp, trees);
}
return true;
}
@Override
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latestSupported();
}
}
您可以看到,我们可以访问与给定的带注释元素关联的TreePath
。对于每个方法,我们只需println()
方法树,它提供了方法的内容
使用您的示例,以下是编译期间程序的输出:
@PrintMethod()
private boolean testMethod(String input) {
if (input != null) {
return true;
}
return false;
}
让它在IDE中工作是一回事,但在jar文件中打包代码后检测它们又是另一回事
public static List<Class> getPackageClassListHavingAnnotation(String pPackageName,
Class<? extends Annotation> pAnnotation) throws Exception
{
try
{
List<Class> classList = getPackageClassList(pPackageName);
if ((pAnnotation == null) || (classList == null)) return classList;
List<Class> resultList = new ArrayList<Class>(classList.size());
outerLoop:
for (Class clazz : classList)
{
try
{
for (Method method : clazz.getMethods())
{
if (method.isAnnotationPresent(pAnnotation))
{
resultList.add(clazz);
continue outerLoop;
}
}
}
catch (Throwable e)
{
}
}
return (resultList.isEmpty()) ? null : resultList;
}
catch (Exception e)
{
return null;
}
}
公共静态列表getPackageClassListHavingAnnotation(字符串pPackageName,
类使其在IDE中工作是一回事,但在jar文件中打包代码后检测它们又是另一回事。下面的代码可以同时管理这两者
public static List<Class> getPackageClassListHavingAnnotation(String pPackageName,
Class<? extends Annotation> pAnnotation) throws Exception
{
try
{
List<Class> classList = getPackageClassList(pPackageName);
if ((pAnnotation == null) || (classList == null)) return classList;
List<Class> resultList = new ArrayList<Class>(classList.size());
outerLoop:
for (Class clazz : classList)
{
try
{
for (Method method : clazz.getMethods())
{
if (method.isAnnotationPresent(pAnnotation))
{
resultList.add(clazz);
continue outerLoop;
}
}
}
catch (Throwable e)
{
}
}
return (resultList.isEmpty()) ? null : resultList;
}
catch (Exception e)
{
return null;
}
}
公共静态列表getPackageClassListHavingAnnotation(字符串pPackageName,
等级