java 自定义BufferedReader

class mybufferedreader {
    private filereader r;

    public mybufferedreader(filereader r) {
        this.r = r;
    }

    //可以一次读一行数据的方法
    public string myreadline() throws ioexception {
        //定义一个临时容器。原bufferedreader封装的是字符数组。
        //我们定义一个stringbuild容器。因为最终还是要将数据变成字符串。
        stringbuilder sb = new stringbuilder();
        int ch = 0;
        while ((ch = r.read()) != -1) {
            if (ch == '\r')
                continue;
            if (ch == '\n')
                return sb.tostring();
            else
                sb.append((char) (ch));
        }

        if (sb.length() != 0)
            return sb.tostring();
        return null;
    }

    public void myclose() throws ioexception {
        r.close();
    }
}


public class mybufferedreaderdemo {
    public static void main(string[] args) throws ioexception {
        filereader fr = new filereader("buf.txt");
        mybufferedreader mybuf = new mybufferedreader(fr);
        string line = null;
        while ((line = mybuf.myreadline()) != null) {
            system.out.println(line);
        }
        mybuf.myclose();
    }
}