文件复制通道

fromFile.exists()
fromFile.isFile()

// 复制文件
                File newToFile = new File(toPath);
                newToFile.createNewFile();
                FileInputStream inFile = new FileInputStream(fromFile);
                FileOutputStream outFile = new FileOutputStream(newToFile);
                FileChannel inChannel = inFile.getChannel();
                FileChannel outChannel = outFile.getChannel();
                long bytesWritten = 0;
                long byteCount = inChannel.size();
                while (bytesWritten < byteCount) {
                    bytesWritten += inChannel.transferTo(bytesWritten,byteCount - bytesWritten, outChannel);
                }
                inFile.close();
                outFile.close();