Java Array setDouble()用法及代碼示例

java.lang.reflect.Array.setDouble()是Java中的內置方法，用於將指定的double值設置為給定對象數組的指定索引。

用法:

Array.setDouble(Object []array, int index, double value)

參數：此方法采用三個參數：

• array:這是要更新的Object類型的數組。
• index:這是要更新的數組的索引。
• value:這是要在給定數組的給定索引處設置的double值。

異常：此方法引發以下異常：

• NullPointerException –當數組為null時。
• IllegalArgumentException–當給定的對象數組不是數組時。
• ArrayIndexOutOfBoundsException–如果給定的索引不在數組的大小範圍內。

下麵是Array.setDouble()方法的實現：

示例1:

// Java code to demonstrate setDouble() 
// method of Array class 
  
import java.lang.reflect.Array; 
  
public class GfG { 
  
    // main method 
    public static void main(String[] args) 
    { 
        // Declaring and defining double array 
        double f[] = { 1.0, 2.0, 3.0 }; 
  
        // printing the array 
        System.out.print("Before Set : "); 
        for (double x : f) { 
            System.out.print(x + " "); 
        } 
  
        double value = 400.0; 
  
        // setDouble method of class Array 
        Array.setDouble(f, 1, value); 
  
        // printing array 
        System.out.print("\nAfter Set : "); 
        for (double x : f) { 
            System.out.print(x + " "); 
        } 
    } 
}

輸出：

Before Set : 1.0 2.0 3.0 
After Set : 1.0 400.0 3.0

示例2:演示java.lang.NullPointerException

// Java code to demonstrate setDouble() 
// method of Array class 
  
import java.lang.reflect.Array; 
  
public class GfG { 
  
    // main method 
    public static void main(String[] args) 
    { 
        // Declaring and defining double array to null 
        double b[] = null; 
  
        try { 
            double c = 1.0; 
  
            // setDouble method of class Array 
            // passing null array in parameters 
            Array.setDouble(b, 5, c); 
        } 
        catch (Exception e) { 
            System.out.println("Exception : " + e); 
        } 
    } 
}

輸出：

Exception : java.lang.NullPointerException

示例3:演示java.lang.ArrayIndexOutOfBoundsException

// Java code to demonstrate setDouble() 
// method of Array class 
  
import java.lang.reflect.Array; 
  
public class GfG { 
  
    // main method 
    public static void main(String[] args) 
    { 
        // Declaring and defining double array 
        double b[] = { 1.0, 2.0, 3.0 }; 
  
        try { 
            double c = 1.0; 
  
            // setDouble method of class Array 
            // passing index 5 when size is 3 
            Array.setDouble(b, 5, c); 
        } 
        catch (Exception e) { 
            System.out.println("Exception : " + e); 
        } 
    } 
}

輸出：

Exception : java.lang.ArrayIndexOutOfBoundsException

示例4:演示java.lang.IllegalArgumentException

// Java code to demonstrate setDouble() 
// method of Array class 
  
import java.lang.reflect.Array; 
  
public class GfG { 
  
    // main method 
    public static void main(String[] args) 
    { 
        // Declaring and defining double variable 
        double b = 2.0; 
        try { 
            double c = 1.0; 
            // setDouble method of class Array 
            // passing a variable as parameter 
            // when an array is required instead 
            Array.setDouble(b, 5, c); 
        } 
        catch (Exception e) { 
            System.out.println("Exception : " + e); 
        } 
    } 
}

輸出：

Exception : java.lang.IllegalArgumentException: Argument is not an array