秒懂数组拷贝，感知新境界，java 编程思维百度云

//**************************************************************

private static void copySelf() {

int[] ids = { 1, 2, 3, 4, 5 };

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

//System.arraycopy(src, srcPos, dest, destPos, length);

// 把从索引 0 开始的 2 个数字复制到索引为 3 的位置上

System.arraycopy(ids, 0, ids, 3, 2);

System.out.println(Arrays.toString(ids));//[1, 2, 3, 1, 2]

}

private static void copyToOther() {

int[] ids = { 1, 2, 3, 4, 5 };

//将数据的索引 1 开始的 3 个数据复制到目标的索引为 0 的位置上

int[] other = new int[5];

System.arraycopy(ids, 1, other, 0, 3);

System.out.println(Arrays.toString(ids));//[1, 2, 3, 4, 5]深复制

System.out.println(Arrays.toString(other));//[2, 3, 4, 0, 0]

}

}

2、Object 数组复制

//如果是类型转换问题，获取整形

private static void getIntegerArrayFromObjectArray() {

Object[] obj1 = { 1, 2, 3, "4", "5" };

Integer[] obj2 = new Integer[5];

try {

System.arraycop

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y(obj1, 0, obj2, 0, obj1.length);

} catch (Exception e) {

System.out.println("transfer exception:"+e);

}

System.out.println(Arrays.toString(obj1));

System.out.println(Arrays.toString(obj2));

}

//获取 Object 数组中的字符串类型数据

private static void getStringArrayFromObjectArray1() {

Object[] obj3 = { 1, 2, 3, "4", "5" };

String[] obj4 = new String[5];

try {

System.arraycopy(obj3, 2, obj4, 2, 3);

} catch (Exception e) {

//transfer exception:java.lang.ArrayStoreException

System.out.println("transfer exception:"+e);

}

System.out.println(Arrays.toString(obj3));

//[null, null, null, null, null]

System.out.println(Arrays.toString(obj4));

}

//获取 Object 数组中的字符串类型数据

private static void getStringArrayFromObjectArray2() {

Object[] obj3 = { 1, 2, 3, "4", "5" };

String[] obj4 = new String[5];

try {

System.arraycopy(obj3, 3, obj4, 3, 2);

} catch (Exception e) {

System.out.println("transfer exception:"+e);

}

System.out.println(Arrays.toString(obj3));

//[null, null, null, 4, 5]

System.out.println(Arrays.toString(obj4));

obj3[3] = "zhangssan";

System.out.println("查看是浅复制还是深复制~~~~~");

System.out.println(Arrays.toString(obj3));

System.out.println(Arrays.toString(obj4));

}

3、多维数组复制

//多维数组

public static void twoArray() {

int[] arr1 = {1, 2};

int[] arr2 = {3, 4};

int[] arr3 = {5, 6};

int[][] src = new int[][]{arr1, arr2, arr3};

print("原始模样：", src);

int[][] dest = new int[3][];

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

System.out.println("改变前");

print("src = ", src);

print("dest = ", dest);

//原数组改变后观察新数组是否改变，改变->浅复制，不改变->深复制

src[0][0] = -1;

System.out.println("改变后");

print("src = ", src);

print("dest = ", dest);

}

4、对象数组复制

//对象复制

private static void beanCopy() {

User user1 = new User("zs",18);

User user2 = new User("ls",18);

User user3 = new User("ww",18);

User[] userArraySrc = {user1, user2, user3};

User[] userArrayDest = new User[3];

System.out.println("对象复制，原始模样："+Arrays.toString(userArraySrc));

System.arraycopy(userArraySrc, 0, userArrayDest, 0, userArraySrc.length);

System.out.println("userArrayDest," + Arrays.toString(userArrayDest));

System.out.println("------------改变原对象------------------");

userArraySrc[0] = new User("su",20);

System.out.println("***" + Arrays.toString(userArraySrc));

System.out.println("***" + Arrays.toString(userArrayDest));

}

//二维数组 toString()

private static void print(String string, int[][] arr) {

System.out.print(string);

for (int[] a : arr) {

for (int i : a) {

System.out.print(i + " ");