String name();
String group();
}
清单2:Description.java
/**
*
*/
packagecom.magc.annotation;
importjava.lang.annotation.Documented;
importjava.lang.annotation.ElementType;
importjava.lang.annotation.Retention;
importjava.lang.annotation.RetentionPolicy;
importjava.lang.annotation.Target;
/**
* @authormagc
*
* 定义描述信息value
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Documented
public@interfaceDescription {
String value();
}
清单3:Utility.java
packagecom.magc.annotation;
@Description(value = "这是一个有用的工具类")
publicclassUtility {
@Author(name = "haoran_202",group="com.magc")
publicString work()
{
return"work over!";
}
}
注：这是个普通的Java类，运行了@Description和@Author注解。
清单3:AnalysisAnnotation.java
packagecom.magc.annotation;
importjava.lang.reflect.Method;
publicclassAnalysisAnnotation {
/**
* 在运行时分析处理annotation类型的信息
*
*
*/
publicstaticvoidmain(String[] args) {
try{
//通过运行时反射API获得annotation信息
Class rt_class = Class.forName("com.magc.annotation.Utility");
Method[] methods = rt_class.getMethods();
booleanflag = rt_class.isAnnotationPresent(Description.class);
if(flag)
{
Description description = (Description)rt_class.getAnnotation(Description.class);
System.out.println("Utility's Description--->"+description.value());
for(Method method : methods) {
if(method.isAnnotationPresent(Author.class))
{
Author author = (Author)method.getAnnotation(Author.class);
System.out.println("Utility's Author--->"+author.name()+" from "+author.group());
}
}
}
} catch(ClassNotFoundException e) {
e.printStackTrace();
}
}
}
注：这是个与自定义@Description和@Author配套的基础框架或工具类，通过此类来获得与普通Java类Utility.java关联的信息,即描述和作者。
运行AnalysisAnnotation,输出结果为：
Utility's Description--->这是一个有用的工具类
Utility's Author--->haoran_202 from com.magc