谁能给个关于java源程序的预处理的详细实例啊??

意思是：将一个txt文本（含注释）的内容读入，然后再写出，写出时需要把注释去掉，求实例！！

注释是什么样的注释啊？是“//”吗？，我就默认为是双斜杠了

public static void main(String[] args) {
BufferedReader reader = null;
BufferedWriter writer = null;
String info = null;
try {
//从a.txt读取数据
reader = new BufferedReader(new FileReader("a.txt"));
//把a.txt中的数据写到b.txt文件里，当然是经过处理的。
writer = new BufferedWriter(new FileWriter("b.txt"));
while((info = reader.readLine()) != null) {
System.out.println(info);
if(info.contains("//")) {
info = info.substring(2,info.length() - 1);
}
writer.write(info+"\n");
writer.flush();

}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
if(reader != null) {
reader.close();
reader = null;
}
if(writer != null) {
writer.close();
writer = null;
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}