System.arraycopy方法实现数组的复制

/**

 * System.arraycopy的方法原型

 * @param src       要复制的源数组

 * @param srcPos    源数组要复制的起始位置（从0开始）

 * @param dest      要复制的目标数组

 * @param destPos   目标数组的起始位置（从0开始）

 * @param length    要复制的长度

*/

public static native void arraycopy(Object src,  int  srcPos,

            Object dest, int destPos, int length);

public static void main(String[] args) {

    int[] nums = {1024, 1025, 1026, 1027, 1028};

    int[] copyOfNums = new int[nums.length];

    System.arraycopy(nums, 0, copyOfNums, 0, nums.length);

    //修改拷贝数组的元素

    copyOfNums[3] = 1234;

    //观察原数组有无变化

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

}

String[] names = {"王昭君", "赵飞燕", "陈圆圆", "杨玉环", "苏妲己"};

System.out.println("原数组中每个元素的哈希码：");

for(String name : names) {

    System.out.print(Integer.toHexString(name.hashCode()) + ", ");

}

String[] copyOfNames = new String[names.length];

System.arraycopy(names, 0, copyOfNames, 0, names.length);

copyOfNames[1] = "洛神甄氏";

System.out.println("\n复制数组中每个元素的哈希码，1号元素的哈希码已经发生了改变：");

for(String name : copyOfNames) {

    System.out.print(Integer.toHexString(name.hashCode()) + ", ");

}

System.out.println();

//修改copyOfNames中元素后的原数组内容没有改变

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

//实体类

public class Beauty {

    private String name;

    private int level;

    private double face;

    public Beauty() {}

    public Beauty(String name, int level, double face) {

        this.setName(name);

        this.setLevel(level);

        this.setFace(face);

    }

    @Override

    public String toString() {

        return name + ", " + level + ", " + face;

    }

    //省略 getters/setters

}

//测试方法

public class ArraycopyDemo {

    public static void main(String[] args) {

        Beauty[] beauties = new Beauty[5];

        beauties[0] = new Beauty("王昭君", 5, 86.25);

        beauties[1] = new Beauty("赵飞燕", 6, 76.25);

        beauties[2] = new Beauty("陈圆圆", 7, 56.25);

        beauties[3] = new Beauty("杨玉环", 8, 66.25);

        beauties[4] = new Beauty("苏妲己", 9, 96.25);

        Beauty[] newBeauties = new Beauty[beauties.length];

        System.arraycopy(beauties, 0, newBeauties, 0, beauties.length);

        //修改复制后数组元素的属性

        newBeauties[1].setName("洛神甄氏");

        //打印原数组中的内容，观察1号元素的name属性，已经被修改了

        for(Beauty beauty : beauties) {

            System.out.println(beauty);

        }      

    }

}