Java 自定义Annotation

很实用几个例子，在Java开发中，灵活运用可以解决很多问题，比如说持久化实现，还可以配合Struts拦截器解决权限问题，可以控制到方法。

packagecn.annotation;
/**
*DefineAnnotationkeywordsis'@interface'soasclass
*Ifyoudon'tsetdefaultvaluetoattributeoffield
*whenyouquotedefinedAnnotation,youshouldclearanddefine
*attributesthatyoudefineintheAnnotation
*@authorAdministrator
*@since2011/12/21
*
*/
@interfaceMyannotation{
publicStringkey();
publicStringtableName();
publicintyear();
}
publicclassAnnotationDemo01{
@Myannotation(key="yangyang",tableName="talbe",year=23)
publicvoidgetInfo(){
System.out.println("自定义Annotation");
}
publicstaticvoidmain(Stringargs[]){
AnnotationDemo01a1=newAnnotationDemo01();
a1.getInfo();
}
}

packagecn.annotation;
/**
*DefineAnnotationkeywordsis'@interface'soasclass
*Ifyoudon'tsetdefaultvaluetoattributeoffield
*whenyouquotedefinedAnnotation,youshouldclearanddefine
*attributesthatyoudefineintheAnnotation
*@authorAdministrator
*
*/
@interfaceMyannotation02{
publicStringkey()default"key";
publicStringtableName()default"table";
publicintyear()default0;
}
publicclassAnnotationDemo02{
@Myannotation02
publicvoidprintInfo(){
System.out.println("自定Annotation,并设置默认值!");
}

publicstaticvoidmain(String[]args){
AnnotationDemo02a2=newAnnotationDemo02();
a2.printInfo();
}

}

packagecn.annotation;

importjava.lang.annotation.Retention;
importjava.lang.annotation.RetentionPolicy;
/**
*Annoation范围：
*RetentionPolicy.SOURCE此Annotation信息只保留在程序源文件中(.java)
*RetentionPolicy.CLASS此Annotation信息保留在源程序(.java)和编译之后的类文件(.class)中,不加载到Jvm中。默认方式
*RetentionPolicy.RUNTIME此Annotation信息保留在源程序(.java)和编译之后的类文件(.class)中,运行时加载到Jvm中
*@authorAdministrator
*
*/
@Retention(value=RetentionPolicy.RUNTIME)
@interfaceMyannotation04{
publicStringname()default"yangyang";
}

packagecn.annotation;

importjava.lang.annotation.Annotation;
importjava.lang.annotation.Retention;
importjava.lang.annotation.RetentionPolicy;
importjava.lang.reflect.Method;
/**
*通过JAVA反射取Annotation
*只有执行时才会加载到Jvm中，才可以取得Annotation信息
*@authorAdministrator
*
*/
@Retention(value=RetentionPolicy.RUNTIME)
@interfaceMyannotation05{
publicStringname()default"name";
publicStringsex()default"男";
publicintage()default20;
}
classSimple{
publicvoidprintInfo(){
System.out.println("***");
}
}
classSimpleBeanextendsSimple{
@SuppressWarnings("Unchecked")
@Deprecated
@Override
@Myannotation05(name="张三",sex="男",age=25)
publicvoidprintInfo(){
System.out.println("获取Annotaion信息");
}
}
publicclassAnnotationDemo04{
publicstaticvoidmain(String[]args){
Class<SimpleBean>classz=SimpleBean.class;
try{
Methodmethod=classz.getMethod("printInfo",null);
if(method.isAnnotationPresent(Myannotation05.class)){
Myannotation05info=method.getAnnotation(Myannotation05.class);
System.out.println("姓名："+info.name()+"、性别："+info.sex()+"、年龄："+info.age());
}
}catch(Exceptione){
System.out.println(e.getMessage());
}
}
}
转自：http://yangyangmyself.iteye.com/blog/1320032