Java System.arraycopy()用法及代码示例

java.lang.System类为标准输入和输出，加载文件和库或访问外部定义的属性提供了有用的方法。 java.lang.System.arraycopy()方法将源数组从特定的起始位置复制到目标位置(从所提到的位置)。要复制的参数数量由len参数决定。 source_Position到source_Position +长度-1的组件从destination_Position到destination_Position +长度-1复制到目标数组

类声明

public final class System
   extends Object

用法:

public static void arraycopy(Object source_arr, int sourcePos,
                            Object dest_arr, int destPos, int len)
参数：
source_arr:array to be copied from
sourcePos:starting position in source array from where to copy
dest_arr:array to be copied in
destPos:starting position in destination array, where to copy in
len:total no. of components to be copied.

实作

// Java program explaining System class method - arraycopy() 
import java.lang.*; 
public class NewClass 
{ 
    public static void main(String[] args) 
    { 
        int s[] = { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100}; 
        int d[] = { 15, 25, 35, 45, 55, 65, 75, 85, 95, 105}; 
  
        int source_arr[], sourcePos, dest_arr[], destPos, len; 
        source_arr = s; 
        sourcePos = 3; 
        dest_arr = d; 
        destPos = 5; 
        len = 4; 
  
        // Print elements of source 
        System.out.print("source_array:"); 
        for (int i = 0; i < s.length; i++) 
            System.out.print(s[i] + " "); 
        System.out.println(""); 
  
        System.out.println("sourcePos:" + sourcePos); 
         
        // Print elements of source 
        System.out.print("dest_array:"); 
        for (int i = 0; i < d.length; i++) 
            System.out.print(d[i] + " "); 
        System.out.println(""); 
         
        System.out.println("destPos:" + destPos); 
         
        System.out.println("len:" + len); 
         
        // Use of arraycopy() method 
        System.arraycopy(source_arr, sourcePos, dest_arr,  
                                            destPos, len); 
         
        // Print elements of destination after 
        System.out.print("final dest_array:"); 
        for (int i = 0; i < d.length; i++) 
            System.out.print(d[i] + " "); 
    } 
}

输出：

source_array:10 20 30 40 50 60 70 80 90 100 
sourcePos:3
dest_array:15 25 35 45 55 65 75 85 95 105 
destPos:5
len:4
final dest_array:15 25 35 45 55 40 50 60 70 105

相关用法

注：本文由纯净天空筛选整理自 System.arraycopy() in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。