Java中的类 getDeclaredClasses() 方法和示例

Java.lang.Class 类的getDeclaredClasses()方法用于获取该类的类，即私有、公有、受保护或默认的类及其成员，而不是继承的类。该方法以 Class 对象数组的形式返回该类的类。
句法：

public Class[] getDeclaredClasses()
               throws SecurityException

参数：此方法不接受任何参数。
返回值：该方法以Class对象数组的形式返回该类的类。
异常如果存在安全管理器并且不满足安全条件，则此方法将引发SecurityException 。
下面的程序演示了 getDeclaredClasses() 方法。
示例 1：

Java

// Java program to demonstrate
// getDeclaredClasses() method
 
import java.util.*;
 
public class Test {
    public static void main(String[] args)
        throws ClassNotFoundException
    {
 
        // returns the Class object for this class
        Class myClass = Class.forName("Test");
 
        System.out.println("Class represented by myClass: "
                           + myClass.toString());
 
        // Get the classes of myClass
        // using getDeclaredClasses() method
        System.out.println(
            "DeclaredClasses of myClass: "
            + Arrays.toString(
                  myClass.getDeclaredClasses()));
    }
}

输出：

Class represented by myClass: class Test
DeclaredClasses of myClass: []

示例 2：

Java

// Java program to demonstrate
// getDeclaredClasses() method
 
import java.util.*;
 
class Main {
 
    private class Arr {
    };
 
    public static void main(String[] args)
        throws ClassNotFoundException
    {
        // returns the Class object for this class
        Class myClass = Class.forName("Main");
 
        System.out.println("Class represented by myClass: "
                           + myClass.toString());
 
        // Get the classes of myClass
        // using getDeclaredClasses() method
        System.out.println(
            "DeclaredClasses of myClass: "
            + Arrays.toString(
                  myClass.getDeclaredClasses()));
    }
}

输出：

Class represented by myClass: class Main
DeclaredClasses of myClass: [class Main$Arr]

参考： https://docs.oracle.com/javase/9/docs/api/ Java/lang/Class.html#getDeclaredClasses–