java如何实现文件拷贝?

Question

还是利用filereader,filewriter 或者 fileinputstream , fileoutputstream

Answer 1

public static void copyFile(String from_name, String to_name)
      throws IOException
  {
      File from_file = new File(from_name);  // Get File objects from Strings
      File to_file = new File(to_name);      String parent = to_file.getParent();  // The destination directory
      if (parent == null)     // If none, use the current directory
        parent = System.getProperty("user.dir");
      File dir = new File(parent);          // Convert it to a file.
      dir.mkdir();      FileInputStream from = null;  // Stream to read from source
      FileOutputStream to = null;   // Stream to write to destination
      try {
          from = new FileInputStream(from_file);  // Create input stream
          to = new FileOutputStream(to_file);     // Create output stream
          byte[] buffer = new byte[4096];         // To hold file contents
          int bytes_read;                         // How many bytes in buffer               while((bytes_read = from.read(buffer)) != -1) // Read until EOF
              to.write(buffer, 0, bytes_read);            // write
      }
 
      finally {
          if (from != null) try { from.close(); } catch (IOException e) { ; }
          if (to != null) try { to.close(); } catch (IOException e) { ; }
      }
    }