注解的一个示例

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package com.james.annotation;import java.lang.annotation.Documented;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface Description {String value();}

是定义对类的注解

package com.james.annotation;import java.lang.annotation.Documented;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface Name {String originage();String community();}

是定义对方法的注解

package com.james.annotation;@Description(value="This is James' community!")public class Mycommunity {@Name(originage="james",community="DP")public String getName(){return null;}@Name(originage="cindy",community="TX")public String getName2(){return null;}}

将注解应用于类和方法

package com.james.annotation;import java.lang.reflect.Method;import java.util.HashSet;import java.util.Set;public class TestAnnotation {/** * @param args */public static void main(String[] args) throws Exception{String className = "com.james.annotation.Mycommunity";Class cla = Class.forName(className);Method[] methods = cla.getMethods();boolean flag = cla.isAnnotationPresent(Description.class);if(flag){Description des = (Description)cla.getAnnotation(Description.class);System.out.println("描述："+des.value());System.out.println("-------------------");}Set<Method> set = new HashSet<Method>();for(int i=0;i<methods.length;i++){boolean methodFlag = methods[i].isAnnotationPresent(Name.class);if(methodFlag) set.add(methods[i]);}for (Method m:set){Name name = m.getAnnotation(Name.class);System.out.println("Org: "+name.originage());System.out.println("Comm: "+name.community());}}}

分别获取类和方法的注解信息！