Java注解Annotation示例

定义我们的注解类

 

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

// 定义注解运行期间也有效
@Retention(RetentionPolicy.RUNTIME)
// METHOD 定义注解可用于方法上
// TYPE 定义注解可用于类上
@Target( { ElementType.METHOD, ElementType.TYPE })
public @interface Result {
	// 注解属性定义
	String value() default "success";

	String[] arrayAttr() default { "1", "2", "3" };

	String location() default "";

	String type() default "dispatcher";
}

 

测试我们呗注解的类

@Result(location="/index.jsp",value="ajax",type="redirect")
public class AjaxAction {
	public String login() {
		return "success";

	}
	public static void main(String args[]) throws SecurityException, NoSuchMethodException{
		//反射类，看是否是Result注解
		if(AjaxAction.class.isAnnotationPresent(Result.class)){
			//从字节码中获取Result注解和对应的属性
			Result ann = (Result)AjaxAction.class.getAnnotation(Result.class);
			System.out.println(ann.value());
			System.out.println(ann.type());
		}
	}
}

 

参考资料

http://u.115.com/file/f182b68766

http://u.115.com/file/f1395e98c5

http://u.115.com/file/f1dfebea55