是否可以通过Java中的BufferedWriter从文件中删除最后一行？

Question

I have a servlet class. Within the class, I use BufferedWriter#write(String) from Java 6 to create a text file on the fly. When I inspected the file, there is a blank line created at the last line. Is there way I could remove it in a programmatic way via that class? Or should I use different API?

================
data 1 recorded
================
--> a blank line needs in between
================
data 2 recorded
================
--> a blank line needs to be removed at last line

// trimmed down version of doPost method from a servlet class
protected void doPost(.....) {
    ......  
    BufferedReader reader = new BuffereReader(new ...)
    BufferedWriter logger = new BufferedWriter(new...)
    while ((line = reader.readLine()) != null) {
       if (!line.equals("")) {
          try {
              doSomething(line,logger);                
              logger.write("=============\r\n"); // create a footer
              logger.write("\r\n");
          } catch (RuntimeException e) {
              logger.write(" warning! " + e.getMessage() + "\r\n");
              logger.write("=============\r\n"); // create a footer
              logger.write("\r\n");
          } 
      } // end of if stmt
   } // end of while loop
    ....
} // end of doPost method


// trimmed down version
private void doSomething(String line, BufferedWriter logger) {
   logger.write("=============\r\n"); // create a header  
   ....     
   if (...) {
       throw new RuntimeException("data is corrupted");
   } else {
     logger.write("data is good!\r\n");
   }
}

Answer 1

No, you cannot remove it with that class. The API does not provide a way to do that. Instead, your code will have to know if it's dealing with the last line and when it is, skip passing that into the BufferedWriter .

Answer 2

You can iterate through the generated file and store each line into a list if it isn't empty

Then later you can write the new list to a file.

Chances are it's happening because of the way you're writing to the file though. Share your code.