菜鸟请教：文件操作

Question

写文件：
BufferedWriter mBufWriter = null;
      try
      {
         FileWriter fileWriter = new FileWriter(fileName, true);
         mBufWriter = new BufferedWriter(fileWriter);         mBufWriter.write(msg);
         mBufWriter.newLine();         mBufWriter.flush();
         mBufWriter.close();
      }
      catch (Throwable e)
      {
         try { mBufWriter.close(); } catch (Throwable t) {};
      }

Answer 1

FileReader oldf = new FileReader(savePath);
                    FileWriter newf = new FileWriter(newsavePath);
                    int length;
                    char buf[] = new char[16];
                    length = oldf.read(buf);
                    while(length != -1)
                    {
                        newf.write(buf, 0, length);
                        length = oldf.read(buf);
                    }
                    newf.close();
                    oldf.close();

Answer 2

读文件：
 FileInputStream is = null;
is = new FileInputStream(filepath);
BufferedReader in = new BufferedReader(new InputStreamReader(is, "8859_1"));
while (true) {
            // Get next line
            String line = in.readLine();
}

Answer 3

下面的程序是读取文件幷显示到标准输出设备：
BufferedReader in = new BufferedReader(new FileReader("abc.txt"));
String s;
while((s = in.readLine()) != null)
System.out.println(s);