1.arraycopy底层代码：

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2.arraycopy的使用

第一个参数:源数组

第二个参数：在源数组中，被复制的数字开始复制的下标

第三个参数：目标数组

第四个参数：从目标数组中，从第几个下标开始放入复制的数据

第五个参数：从源数组中，一共拿几个数值放到目标数组中

System.arraycopy(result, 0, str, 0, 0);

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 3.使用案例

package Openlab;
import java.util.Arrays;
/*** Arraycopy 用法讲解* str = {"1","2","3","4","5"}* result = {"A","B","C","D","E"}* 实现 {"1","2","3","A","B"}* @author Lenovo**/
public class Arraycopy {public static void main(String[] args) {String [] str = {"1","2","3","4","5"};String [] result = {"A","B","C","D","E"};System.arraycopy(result,0,str,3,result.length-3);System.out.println(Arrays.toString(str));	}
}

运行结果：