Java Arrays copyOf()用法及代碼示例

java.util.Arrays.copyOf()方法在java.util.Arrays類中。它複製指定的數組，使用false截斷或填充(如有必要)，因此副本具有指定的長度。

用法:

 copyOf(int[] original, int newLength)

original–原始數組
newLength–原始數組的副本

// Java program to illustrate copyof method 
import java.util.Arrays; 
  
public class Main 
{ 
    public static void main(String args[]) 
    { 
        // initializing an array original 
        int[] org = new int[] {1, 2 ,3}; 
  
        System.out.println("Original Array"); 
        for (int i = 0; i < org.length; i++) 
            System.out.print(org[i] + " "); 
  
        // copying array org to copy 
        int[] copy = Arrays.copyOf(org, 5); 
  
        // Changing some elements of copy 
        copy[3] = 11; 
        copy[4] = 55; 
  
        System.out.println("\nNew array copy after modifications:"); 
        for (int i = 0; i < copy.length; i++) 
            System.out.print(copy[i] + " "); 
    } 
}

輸出：

Original Array
1 2 3 
New array copy after modifications:
1 2 3 11 55

如果複製的數組的長度大於原始數組會發生什麽？
對於原始數組和新數組中有效的所有索引，兩個數組將具有相同的值。
但是，如果複製的數組長度大於原始數組的長度，則原始索引中丟失的索引的副本數將為零。

// Java program to illustrate copyOf when new array 
// is of higher length. 
import java.util.Arrays; 
  
public class Main  
{ 
  public static void main(String args[])  
  { 
      // initializing an array original 
      int[] org = new int[] {1, 2 ,3}; 
     
      System.out.println("Original Array : \n"); 
      for (int i = 0; i < org.length; i++) 
           System.out.print(org[i] + " ");   
        
       // copying array org to copy  
       // Here, new array has 5 elements - two 
       // elements more than the original array 
       int[] copy = Arrays.copyOf(org, 5); 
    
       System.out.print("\nNew array copy (of higher length):\n"); 
       for (int i = 0; i < copy.length; i++)  
           System.out.print(copy[i] + " "); 
    } 
}

輸出：

Original Array : 
1 2 3 
New array copy (of higher length):
1 2 3 0 0

相關用法

注：本文由純淨天空篩選整理自 Arrays copyOf() 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。