public static void main(String[] args) {
File f = new File(args[0]);
try{
LineNumberReader lnr = new LineNumberReader(new FileReader(f));
FileWriter fw = new FileWriter(new File("aaa.txt"));
public void insertLineInFile(String fileName, String tFileName, int n, String insertStr) throws IOException{
BufferedReader reader = new BufferedReader(new InputStreamReader(
new FileInputStream(fileName)));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream(tFileName)));
String line = reader.readLine();
int num = 0;
while (line != null) {
writer.write(line);
writer.write(0x0d);
writer.write(0x0a);
if( n == ++num){
writer.write(insertStr);
writer.write(0x0d);
writer.write(0x0a);
}
line = reader.readLine();
}
reader.close();
}