java基礎之註解
自定義註解:
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {
String name();
int age();
}
測試代碼:
public class AnnotationTest {
@MyAnnotation(name = "suvue",age=22)
public void addUser(String name,Integer age){
//執行業務邏輯
//...
System.out.println("用戶添加成功!姓名:"+name+" 年齡:"+ age);
}
public static void main(String[] args) throws NoSuchMethodException, IllegalAccessException, InstantiationException, InvocationTargetException {
//java是通過反射機制使註解生效
//獲取類對象
Class<AnnotationTest> aClass = AnnotationTest.class;
//獲取到指定方法
Method aClassMethod = aClass.getMethod("addUser", String.class, Integer.class);
//獲取方法上的指定註解
MyAnnotation aClassMethodAnnotation = aClassMethod.getAnnotation(MyAnnotation.class);
//獲取註解裏的屬性和值
int age = aClassMethodAnnotation.age();
String name = aClassMethodAnnotation.name();
//將信息注入到方法上
AnnotationTest instance = aClass.newInstance();
aClassMethod.invoke(instance,name,age);
}