代碼結構假設我們有一個這樣的結構：class A { @AMethodAnnotation("my-data") public void myMethod() { }}@MyClassAnnotationclass B extends A { @Override public void myMethod() { }}我正在努力實現的目標使用注釋處理，我試圖從AMethodAnnotation位于myMethodclass 內部方法上的注釋中提取數據A。類B擴展了這個類并覆蓋了它的方法myMethod。扭曲的是我想要來自方法的數據，AMethodAnnotation如果它在里面的類有 annotation MyClassAnnotation。我正在獲取帶有注釋的類MyClassAnnotation并循環遍歷 ，在enclosedElements那里我可以檢查它是否有Override注釋，但我不確定如何獲取它覆蓋的方法，因為那是AMethodAnnotation我想要的數據所在的位置。ExecutableElement似乎沒有提供方法來獲得這個。for (Element classElement : roundEnv.getElementsAnnotatedWith(MyClassAnnotation.class)) { // Make sure it's a class if (classElement.getKind() != ElementKind.CLASS) { continue; } // Loop through methods inside class for (Element methodElement : classElement.getEnclosedElements()) { // Make sure the element is a method & has a @Path annotation if (methodElement.getKind() != ElementKind.METHOD) { continue; } // If method has @Override annotation do stuff }}問題有沒有辦法獲得對被覆蓋的方法的引用？有一種方法，您獲取Bis的超類A并循環遍歷enclosedElementsin A，然后您必須驗證方法名稱是否相同，以及參數是否相同且順序相同。但是我發現這種方法需要大量檢查，因此我的問題是是否有更好的方法。
1 回答
慕妹3242003
TA貢獻1824條經驗 獲得超6個贊
我根據評論中發布的鏈接@rmuller 編寫了以下方法。如 Javadoc 和下圖所示，此方法有大量文檔，其中更具可讀性。
/**
* Will find the method which the method <strong>methodElement</strong> is overriding, if any.
* It does this by recursively traversing up the superclass tree of the
* <strong>classElement</strong> and checking if there are methods which override the
* <strong>methodElement</strong>. It will return after it finds the first method with the
* annotation <strong>annotation</strong>.
*
* @param originalClassElement The original class inside which the
* <strong>methodElement</strong> is located.
* @param classElement The class which represents the superclass while recursively
* looking up the tree, it should be equal to the
* <strong>originalClassElement</strong> when first calling this
* method.
* @param methodElement The method for which should be checked if it's overriding
* anything.
* @param annotation The annotation which must be matched before returning the result
* @return Will return the following, the list is written in order:
* <ul>
* <li>The method <strong>methodElement</strong> if <strong>methodElement</strong>
* already has an annotation of the type <strong>annotation</strong></li>
* <li>Null if the method <strong>methodElement</strong> does not have an @Override
* annotation</li>
* <li>Null if the class <strong>classElement</strong> does not have a superclass</li>
* <li>The method element which was found to have the annotation
* <strong>annotation</strong></li>
* </ul>
*/
public ExecutableElement getMethodOverride(TypeElement originalClassElement,
TypeElement classElement, ExecutableElement methodElement,
Class<? extends Annotation> annotation) {
if (methodElement.getAnnotation(annotation) != null) {
// The methodElement which was passed has the required annotation already
return methodElement;
}
if (methodElement.getAnnotation(Override.class) == null) {
// The methodElement which was passed does not have an @Override annotation and is
// therefore not overriding anything.
return null;
}
if (classElement.getSuperclass().getKind() == TypeKind.NONE) {
// Class has no superclass
return null;
}
for (Element elem : classElement.getEnclosedElements()) {
if (elem.getKind() != ElementKind.METHOD) {
// Not a method
continue;
}
// Check if the method inside the superclass overrids the method inside the original
// class
if (this.processingEnv.getElementUtils().overrides(methodElement,
(ExecutableElement) elem, classElement)) {
// Recursively go up the tree and check since this method might also override
// another method
return getMethodOverride(originalClassElement,
this.env.getElementUtils()
.getTypeElement(classElement.getSuperclass().toString()),
(ExecutableElement) elem, annotation);
}
}
// Recursively go up the tree and check there
return getMethodOverride(originalClassElement,
this.env.getElementUtils().getTypeElement(classElement.getSuperclass().toString()),
methodElement, annotation);
}
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