Java 中的构造函数 getAnnotatedReturnType()方法，示例
原文:https://www . geeksforgeeks . org/constructor-getannotatedreturnttype-method-in-Java-with-examples/
构造函数 类的GetanNOtatedRentType()方法用于返回一个表示注释类型的注释类型对象，以指定构造函数对象的返回类型。返回的 AnnotatedType 表示 AnnotatedType 本身或其任何子接口(如 AnnotatedArrayType、AnnotatedParameterizedType、AnnotatedTypeVariable、AnnotatedWildcardType)的实现。AnnotatedType 表示任何类型的潜在注释使用，包括数组类型、参数化类型、类型变量或 Java Virtual Machine 中当前运行的通配符类型。
语法:
public AnnotatedType getAnnotatedReturnType()
参数:此方法不接受任何内容。
返回值:该方法返回一个对象，其类型为，代表该可执行文件所代表的方法或构造函数的返回类型。
下面的程序说明了 getAnnotatedReturnType()方法: 程序 1:
// Java program to demonstrate
// Constructor.getAnnotatedReturnType() method
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.AnnotatedType;
import java.lang.reflect.Constructor;
import java.util.Arrays;
public class GFG {
// main method
public static void main(String[] args)
{
try {
// create class object
Class demo = Demo.class;
// get Constructor object array
// from the class object
Constructor[] cons
= demo.getConstructors();
// get AnnotatedType for return type
AnnotatedType annotatedType
= cons[0]
.getAnnotatedReturnType();
System.out.println(
"Type: "
+ annotatedType
.getType(
.getTypeName());
System.out.println(
"Annotations: "
+ Arrays
.toString(
annotatedType
.getAnnotations()));
}
catch (Exception e) {
e.printStackTrace();
}
}
}
class Demo {
// AnnotatedType is @customAnnotatedType
public @customAnnotatedType Demo()
{
// do stuffs
}
}
// Creating custom AnnotatedType
@Target({ ElementType.TYPE_USE })
@Retention(RetentionPolicy.RUNTIME)
@interface customAnnotatedType {
}
Output:
Type: Demo
Annotations: [@customAnnotatedType()]
程序 2:
// Java program to demonstrate
// Constructor.getAnnotatedReturnType() method
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.AnnotatedType;
import java.lang.reflect.Constructor;
import java.util.Arrays;
public class GFG {
// main method
public static void main(String[] args)
{
try {
// create class object
Class shape = Shape.class;
// get Constructor object array
// from the class object
Constructor[] cons
= shape.getConstructors();
// get AnnotatedType for return type
AnnotatedType annotatedType
= cons[0]
.getAnnotatedReturnType();
System.out.println(
"Type: "
+ annotatedType
.getType()
.getTypeName());
System.out.println(
"Annotations: "
+ Arrays.toString(
annotatedType.getAnnotations()));
}
catch (Exception e) {
e.printStackTrace();
}
}
}
class Shape {
// AnnotatedType is @customAnnotatedType
public @ShapeProperties Shape()
{
// do stuffs
}
}
// Creating custom AnnotatedType
@Target({ ElementType.TYPE_USE })
@Retention(RetentionPolicy.RUNTIME)
@interface ShapeProperties {
}
Output:
Type: Shape
Annotations: [@ShapeProperties()]
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