即使使用了printwriter.close，Printwriter也会创建空文件

Question

I am using PrintWriter but it sometimes creates empty files.

I have also used PrintWriter.close() at the end but it still creates empty file sometimes.

Code:

StringBuilder fileContent = new StringBuilder();
for (Iterator<String> i = fieldMap.values().iterator(); i.hasNext();) 
{
  String fieldValue = i.next();
  LOG.debug("Write information to outputfile:  fieldValue" + fieldValue);
  fileContent.append(fieldValue);
  if (i.hasNext())
    fileContent.append("~");
}

// Member errorMessage is only set in case of fatal error and might
// be appended without risk since in
// this case this content is only written to logger.
fileContent.append(errorMessage);
fileContent.append("\n");

PrintWriter docFileWriter = new PrintWriter(fileName, "UTF-8");
docFileWriter.write(fileContent.toString());
docFileWriter.close();

Answer 1

Be sure, your fileName is valid and your fileContent is not empty (debbuging with condition or add console-outputs).

To test the PrintWriter you can use this short example code:

PrintWriter docFileWriter = new PrintWriter("C:/temp/temp.txt", "UTF-8");
docFileWriter.write("Some special text: Aäç/)!é");
docFileWriter.close();

When your files are sometimes empty but exists, you should keep attention on the fileContent variable.