Java 中的类 getAnnotations()方法，带示例
原文:https://www . geesforgeks . org/class-getannocations-method-in-Java-with-examples/
java.lang.Class 类 的 getAnnotations() 方法用于获取该类中存在的注释。方法返回存在的注释数组。
语法:
public Annotation[] getAnnotations()
参数:该方法不接受任何参数。
返回值:该方法返回一组存在的注释。
下面的程序演示了 getAnnotations()方法。
例 1:
// Java program to demonstrate
// getAnnotations() method
import java.util.*;
import java.lang.annotation.*;
@Deprecated
public class Test {
public Object obj;
public static void main(String[] args)
throws ClassNotFoundException
{
try {
// returns the Class object for this class
Class myClass = Test.class;
System.out.println(
"Class represented by myClass: "
+ myClass.toString());
// Get the annotation
// using getAnnotations() method
System.out.println(
"Annotation of myClass: "
+ Arrays.toString(
myClass.getAnnotations()));
}
catch (Exception e) {
System.out.println(e);
}
}
}
输出:
Class represented by myClass: class Test
Annotation of myClass: [@java.lang.Deprecated()]
例 2:
// Java program to demonstrate
// getAnnotations() method
import java.util.*;
import java.lang.annotation.*;
// create a custom Annotation
@Retention(RetentionPolicy.RUNTIME)
@interface Annotation {
// This annotation has two attributes.
public String key();
public String value();
}
// call Annotation for method
// and pass values for annotation
@Annotation(key = "GFG", value = "GeeksForGeeks")
public class Test {
public Object obj;
public static void main(String[] args)
throws ClassNotFoundException
{
// returns the Class object for this class
Class myClass = Test.class;
System.out.println(
"Class represented by myClass: "
+ myClass.toString());
// Get the annotation
// using getAnnotations() method
System.out.println(
"Annotation of myClass: "
+ Arrays.toString(
myClass.getAnnotations()));
}
}
输出:
Class represented by myClass: class Test
Annotation of myClass: [@Annotation(key=GFG, value=GeeksForGeeks)]
参考:https://docs . Oracle . com/javase/9/docs/API/Java/lang/class . html # getAnnotations–
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