FileReader fr = new FileReader("c:/mydoc/hello.txt");
        BufferedReader br = new BufferedReader(fr);

//下面这句错了吗？
        
        while (String str2 = br.readLine()!= null) {


            System.out.println(str2);
            str2 = br.readLine();
        }
        fr.close();
        br.close();