java学习：使用Java操作文本文件

 FileReader fr = new FileReader("ming.txt");
  char[] buffer = new char[1024];
  int ch = 0;
  while((ch = fr.read())!=-1 )
  {
   System.out.print((char)ch); 
  }
  fr.close();

  InputStreamReader isr = new InputStreamReader(new FileInputStream("ming.txt"));
  while((ch = isr.read())!=-1)
  {
   System.out.print((char)ch); 
  } 
   isr.close();

  BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("ming.txt")));
  String data = null;
  while((data = br.readLine())!=null)
  {
   System.out.println(data); 
  }
  br.close();

  FileWriter fw = new FileWriter("hello.txt");
  String s = "hello world";
  fw.write(s,0,s.length());
  fw.flush();
  fw.close();

  OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("hello2.txt"));
  osw.write(s,0,s.length());
  osw.flush();
  osw.close();

  PrintWriter pw = new PrintWriter(new OutputStreamWriter(new FileOutputStream("hello3.txt")),true);
  pw.println(s); 
  pw.close();