import json
import logging
 
class JsonFilter(logging.Filter):
 
 ip = 'IP'
 source = 'APP'
 
 def filter(self, record):
  record.ip = self.ip
  record.username = self.source
  return True
 
if __name__ == '__main__':
 
 formate = json.dumps({
  "time": "%(asctime)s",
  "levelname": "%(levelname)s",
  "levelno": "%(lineno)d",
  "ip": "%(ip)s",
  "source": "%(source)s"
 })
 logging.basicConfig(level=logging.DEBUG,
      format=formate)
 logger = logging.getLogger()
 filter_ = JsonFilter()
 logger.addFilter(filter_)
 
 logger.debug('A debug message')
 
 filter_.ip = '127.0.0.1'
 filter_.source= 'china'
 logger.info('A message for test')

public static void printStringToFile(String str) {
 File file = new File(Environment.getExternalStorageDirectory(), "new.json");
 Log.d("Lyb", "path = " + file.getAbsolutePath());
 FileWriter writer = null;
 try {
  Log.d("Lyb", "createNewFile");
  if (!file.exists()) {
   file.createNewFile();
  }else {
   file.delete();
   file.createNewFile();
  }
  writer = new FileWriter(file, true);
  writer.write(str);
  writer.flush();
  writer.close();
  writer = null;
 } catch (IOException e) {
  e.printStackTrace();
 } finally {
  try {
   if (writer != null) {
    writer.close();
   }
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
}