Question

利用JAVA语言编写一个 名为copy的程序 实现文件的拷贝功能，应该怎样做？

Answer 1

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
public class Copy {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
if(args.length!=2){
System.out.print("没有输入正确数目的参数，程序退出！");
System.exit(0);
}
File fileS = new File("./"+args[0]);
File fileD = new File("./"+args[1]);
if(fileD.exists())System.out.println("目标文件 "+args[1]+" 已存在！");
byte[] temp = new byte[50];
int totalSize = 0;
try {
FileInputStream fr = new FileInputStream(fileS);
FileOutputStream fo = new FileOutputStream(fileD);
int length = 0;
while((length = fr.read(temp, 0, temp.length)) != -1){
totalSize += length;
fo.write(temp, 0, length);
}
System.out.println("文件 "+args[0]+" 有 "+totalSize+" 个字节");
System.out.println("复制完成！");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("源文件 "+args[0]+" 不存在！");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}