拷贝文件到新路径的方法

Question

java.io.File的API没有提供copy的接口，你可以自己实现

Answer 1

用执行外部命令的方式好了，“copy”

Answer 2

import java.io.*;public class CopyFile
{
public static void copy(String from_name,String to_name) throws IOException
{ 
File from_file=new File(from_name);
File to_file=new File(to_name);

if(!from_file.exists()) abort("no such file:" + from_name);
if(!from_file.isFile()) abort("a directory:" + from_name);
if(!from_file.canRead()) abort("can't read:" + from_name);

if(to_file.isDirectory()) to_file=new File(to_file,from_file.getName());

if(to_file.exists())
{
if(!to_file.canWrite())
abort("Destination File is unwriteable:" + to_name);
System.out.print("Overwrite existing file:" + to_file.getName() + "? (Y/N):");
System.out.flush();
BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
String res=in.readLine();
if(!res.equals("Y")&& !res.equals("y")) abort("not overwrite:" + to_name);
}else{
String parent=to_file.getParent();
if(parent==null) parent=System.getProperty("user.dir");
File dir=new File(parent);
if(!dir.exists()) abort("destination file is not exist:" + parent);
if(dir.isFile()) abort("destination file is not a directory:" + parent);
if(!dir.canWrite()) abort("can't write:" + parent);
}

FileInputStream from=null;
FileOutputStream to=null;
try{
  from=new FileInputStream(from_file);
  to=new FileOutputStream(to_file);
  byte[] buffer=new byte[4096];
  int bytes_read;
  while((bytes_read=from.read(buffer))!=-1)
   to.write(buffer,0,bytes_read);
}
finally{
 if(from!=null) try{from.close();} catch(IOException e) { ;}
 if(to!=null) try{to.close();} catch(IOException e) {;}
}

}

public static void abort(String msg) throws IOException
{
throw new IOException("filecopy:" + msg);
}

public static void main(String args[]) throws IOException
{
CopyFile cp=new CopyFile();
cp.copy(args[0],args[1]);
}
}

Answer 3

这是一个copy 文件的java程序
试试看