java 高效率文件复制

　　　　　　　　　 File sourFile = new File(start);　　//来源文件
                File tarFile = new File(end); 4                 if(!tarFile.exists()){
                    tarFile.mkdirs();
                }10                 if(!sourFile.exists()){
                    System.out.println("跳出本次循环"+start);
                    continue;
                }
                FileInputStream fis = null;
                FileOutputStream fos = null;19                 FileChannel in = null;
                FileChannel out = null;22                 try {
                    
                     
                    fis = new FileInputStream(new File(start));
                    fos = new FileOutputStream(new File(end+imagess));28                     
                    in = fis.getChannel();
                    out = fos.getChannel();
                    smallOut = smallFos.getChannel();
                    
                    in.transferTo(0, in.size(), out);35                 } catch (Exception e) {
                    e.printStackTrace();
                }finally{
                    in.close();40                     out.close();42                     fos.close();
                    fis.close();
                }