注释解析类

This class will parse our annotation and trigger some other invocations related to what we want. 
注释解析类的基本观点是用Java反射读取有关注释的信息

The basic idea behind the annotation parser is using Java reflections to access the annotation information/attributes etc. 

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

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@interface Test {
	String info() default "";
}

class Annotated {
	@Test(info = "AWESOME")
	public void foo(String myParam) {
		System.out.println("This is " + myParam);
	}
}

class TestAnnotationParser {
	public void parse(Class clazz) throws Exception {
		Method[] methods = clazz.getMethods();

		for (Method method : methods) {
			if (method.isAnnotationPresent(Test.class)) {
				Test test = method.getAnnotation(Test.class);
				String info = test.info();

				if ("AWESOME".equals(info)) {
					System.out.println("info is awesome!");
					// try to invoke the method with param
					method.invoke(Annotated.class.newInstance(), info);
					//用这种办法生成一种被注释的类
				}
			}
		}
	}

}

public class Demo {
	public static void main(String[] args) throws Exception {
		TestAnnotationParser parser = new TestAnnotationParser();
		parser.parse(Annotated.class);
	}
}

原文： http://isagoksu.com/2009/development/java/creating-custom-annotations-and-making-use-of-them/