在java中克隆二维字符串数组

Question

我正在写一个有父节点的程序。该父节点有一个2d字符串数组和包含父2d字符串数组但经过修改的子节点。但是，当我创建子对象的2d数组时，它一直使用对parents数组的引用。这样，在子数组创建结束时，父数组就拥有了所有子数组的修改。我尝试使用System.arraycopy、Arrays.copyOf创建一个复制构造函数，但都无济于事。下面是构造函数

public class Board
{
 private String[][] Gameboard;
 public Board(Board parent)
 {
  this.Gameboard = parent.Gameboard;
 }
}

我还尝试了遍历数组并逐个分配字符串，但也不起作用。我像这样调用构造函数：

Board temp = new Board(parent);

Answer 1

试试这个：

class parent {
    static String[][] Gameboard = new String[5][5];

    public static void main (String[] args) {
        for(int i = 0; i < 5; i++) {
            for(int j = 0; j < 5; j++) {
                Gameboard[i][j] = "" + j;
            }
        }
        Board b = new Board();
    }
} 

class Board { 
    private String[][] Gameboard;

    public Board() { 
        this.Gameboard = parent.Gameboard; 
        for(int i = 0; i < 5; i++) {
            for(int j = 0; j < 5; j++) {
                System.out.print("" + this.Gameboard[i][j]);
            }
            System.out.print("\n");
        }   
        System.out.print("Lenght Of Class Boar.GameBoard =" + this.Gameboard.length);  
    } 
}

​

​

Answer 2

您可以使用复制构造函数，如下所示：

public class Test {
    String[][] arr2D = new String[2][2];

    public Test() {
    }

    public Test(Test t) {
        this.arr2D = deepCopy(t.arr2D);
    }

    // deepCopy
    private String[][] deepCopy(String[][] arr2D) {
    String[][] arr2D2 = new String[arr2D.length][arr2D.length];
      for (int i = 0; i < arr2D.length; i++) {
         for (int j = 0; j < arr2D.length; j++) {
            arr2D2[i][j] = arr2D[i][j];
         }
      }
       return arr2D2;
    }

    public void setArr2D(String[][] arr2D) {
        for (int i = 0; i < arr2D.length; i++) {
            for (int j = 0; j < arr2D.length; j++) {
                arr2D[i][j] = i + "row " + j + "column";
            }
        }
    }

    public String[][] getArr2D() {
        return this.arr2D;
    }

    public static void main(String[] args) {
        Test t1 = new Test();
        t1.setArr2D(t1.getArr2D());
        System.out.println(Arrays.deepToString(t1.getArr2D()));
        Test t2 = new Test(t1);
        t2.setArr2D(t1.getArr2D());
        System.out.println(Arrays.deepToString(t2.getArr2D()));
    }
}