文件拷贝,可以覆盖

public static void saveFileToFile(String F1,String F2){            //实现文件对拷,从F1拷贝到F2,若F2存在则会被覆盖;适用于任何文件.
        FileInputStream fis = null;
        FileOutputStream fos = null;
        try{
            fis = new FileInputStream(new File(F1));    //建立文件输入流
            
            File file = new File(F2);
            fos = new FileOutputStream(F2);
            byte[] buffer=new byte[1024];
            int len;
            while((len=fis.read(buffer))!=-1){
                fos.write(buffer,0,len);  
            }
        }
        catch(FileNotFoundException ex){
            System.out.println("Source File not found:"+F1);
        }
        catch(IOException ex){
            System.out.println(ex.getMessage());
        }
        finally{
            try{
                if(fis!=null) fis.close();      //一定要进行文件的关闭,否则在新文件会是空的!
                if(fos!=null) fos.close();
            }
            catch(IOException ex){
                System.out.println(ex);
            }
        }
    }