annotation的使用

T.java

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;
import java.lang.NoSuchMethodException;

public class T {
    public static void main(String[] args) throws Exception {
        executeWithAnnotationSupport(T.class, "doSomething");
    }

    @InProgress
    public static void doSomething() {
    }

    public static void executeWithAnnotationSupport(Class<?> clazz, String methodName) throws Exception {
        Method[] ms = clazz.getMethods();
        for (Method m : ms) {
            if (m.getName().equals(methodName)) {
                InProgress inProgress = m.getAnnotation(InProgress.class);
                if (inProgress != null) {
                    System.out.format("method '%s' for class '%s' is still work in progress\n", methodName, clazz.getName());
                }
            }
        }
    }
}

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@interface InProgress {
}