我有一个名为 Client 的抽象类。我怎样才能访问在子类的调用方法上声明的注释?处理此问题的最佳方法是什么?
public abstract class Client {
protected void synchronize() {
// How can I get the Annotation defined on inheriting class?
StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
StackTraceElement lastStackElement = stackTraceElements[stackTraceElements.length-1] ;
Method m = this.getClass().getMethod(lastStackElement.getMethodName(), String.class, int.class);
m.getAnnotation(Cache.class);
// synchronize data from server
}
}
.
public class OrderClient extends Client {
@Cache(minute = 5)
public void synchronizrWithCustomerId(String customerId) {
// So some stuff setup body and header
super.synchronize();
}
}
最佳答案
根据您的示例,此代码运行良好:
public class TestS1 {
public abstract class Client {
protected void synchronize() throws NoSuchMethodException {
// How can I get the Annotation defined on inheriting class?
StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
StackTraceElement lastStackElement = stackTraceElements[2];
//注意这里:stackTraceElements[
2]
Method m = this.getClass().getMethod(lastStackElement.getMethodName(), String.class);
Cache annotation = m.getAnnotation(Cache.class);
System.out.println("Cache.minute = " + annotation.minute());
// synchronize data from server
}
}
你还需要用@Retention(RetentionPolicy.RUNTIME)
标记你的注释
@Retention(RetentionPolicy.RUNTIME)
@interface Cache {
int minute();
}
public class OrderClient extends Client {
@Cache(minute = 5)
public void synchronizrWithCustomerId(String customerId) throws NoSuchMethodException {
// So some stuff setup body and header
super.synchronize();
}
}
public void doTest() throws NoSuchMethodException {
OrderClient oc = new OrderClient();
oc.synchronizrWithCustomerId("blabla");
}
public static void main(String[] args) throws NoSuchMethodException {
TestS1 t = new TestS1();
t.doTest();
}
}
输出是:Cache.minute = 5
关于Java - 定义和访问注释?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/14050609/