自定義註解---反射獲取註解案例
自定義註解:
package Demo01;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(value = ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface Over {
String name() default "";
int age() default -1;
}
反射獲取註解:
package Demo01;
import java.lang.annotation.Annotation;
@Over(name = "張三", age = 18)
public class Demo1 {
public static void main(String[] args) {
Demo1 dd = new Demo1();
dd.test1("張琳");
}
public void test1(String name) {
try {
// 獲得這個類的類物件
Class clazz = this.getClass().forName("Demo01.Demo1");
// 判斷類上是否有此註解
boolean exit = clazz.isAnnotationPresent(Over.class);
System.out.println(exit);
// 得到註解陣列
Annotation[] annotation = clazz.getAnnotations();
// 遍歷陣列
for (Annotation a : annotation) {
// 獲得註解上的屬性;
int age1 = ((Over) a).age();
String s1 = ((Over) a).name();
System.out.println(s1 + ":" + age1);
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}