Java Class getDeclaredFields()用法及代碼示例

java.lang.Class類的getDeclaredFields()方法用於獲取此類的字段，這些字段是私有，公共，受保護或默認值及其成員的字段，而不是繼承的成員。該方法以Field對象數組的形式返回此類的字段。

用法:

public Field[] getDeclaredFields()
               throws SecurityException

參數：此方法不接受任何參數。

返回值：此方法以Field對象數組的形式返回此類的字段。

異常如果存在安全管理器且不滿足安全條件，則此方法將引發SecurityException。

下麵的程序演示了getDeclaredFields()方法。

示例1:

// Java program to demonstrate getDeclaredFields() 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 fields of myClass 
        // using getDeclaredFields() method 
        System.out.println( 
            "DeclaredFields of myClass: "
            + Arrays.toString( 
                  myClass.getDeclaredFields())); 
    } 
}

輸出：

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

示例2:

// Java program to demonstrate getDeclaredFields() method 
  
import java.util.*; 
  
class Main { 
  
    public Object obj; 
  
    Main() 
    { 
  
        class Arr { 
        }; 
  
        obj = new 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 fields of myClass 
        // using getDeclaredFields() method 
        System.out.println( 
            "DeclaredFields of myClass: "
            + Arrays.toString( 
                  myClass.getDeclaredFields())); 
    } 
}

輸出：

Class represented by myClass: class Main
DeclaredFields of myClass: [public java.lang.Object Main.obj]

參考： https://docs.oracle.com/javase/9/docs/api/java/lang/Class.html#getDeclaredFields–

相關用法

注：本文由純淨天空篩選整理自srinam大神的英文原創作品 Class getDeclaredFields() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。