Java FileUtils：从文件中删除特定行

Question

How can I delete a specific line (by index) from a text file with the class org.apache.commons.io.FileUtils ?

The index of the line to be deleted already know him, so I need some method that I delete a specific line from a file.

Answer 1

You can use lineIterator function of the same library.

• Get the Line Iterator of the file
• Iterate over the lineIterator and write it to the temporary file.
• Maintain the index of the current iteration. If in the above step, the line number matches the number you want to skip, dont write it to temporary file.
• Close both file (handle the case if you exceptions. you may want to use finally as well)
• delete old file.
• rename the temporary file to new file

fyi, Iterator loads lazily into memory and drops reference to previous line when next is called. [@Obicere : Also, I can not comment directly to the question but loading all the lines to memory does not like a good idea. ]