java数组复制的几种常见用法

1.1.1System.arraycopy的用法

       int[] src = {1,3,5,7,9,11,13,15,17};

       int[] dest = {2,4,6,8,10,12,14,16,18,20};

       //从src中的第一个元素起复制三个元素，即1，3，5复盖到dest第2个元素开始的三个元素

       System.arraycopy(src, 0, dest, 1, 3);

       System.out.println(Arrays.toString(dest));

结果为：[2, 1, 3, 5, 10, 12, 14, 16, 18, 20]

1.1.2Arrays.copyOf的用法

      int[] src = {1,3,5,7,9,11,13,15,17};

      int[] dest = {2,4,6,8,10,12,14,16,18,20};

    //copyOf(是复制src数组从0开始的两个元素到新的数组对象)

int[] copyof=Arrays.copyOf(src, 2);

      System.out.println(Arrays.toString(copyof));

结果为：[1, 3]

 

1.1.3 Arrays.copyOfRange的用法

      int[] src = {1,3,5,7,9,11,13,15,17};

      int[] dest = {2,4,6,8,10,12,14,16,18,20};

//copyRange(从src数组中从0开始的第二个元素到第五个元素复制到新数组，含头不含尾)

      int[] copyofRange=Arrays.copyOfRange(src, 2,6);

      System.out.println(Arrays.toString(copyofRange));

结果为：[5, 7, 9, 11]