用Reader模拟BufferedReader的readLine()功能

import java.io.FileReader;

public class Moni1 {
    
    public static void main(String[] args) throws Exception {
     MyReader reader=new MyReader(new FileReader("b.txt"));
     String s=null;
     while((s=reader.readerline())!=null) {
         System.out.println(s);
     }
     reader.close();
    }
}
//Reader类
class MyReader{
    private FileReader r;
    //返回值为字符串的有参方法
    public  MyReader(FileReader r) {
        // TODO Auto-generated constructor stub
        this.r=r;
    }
    public String readerline( ) throws Exception {
        StringBuffer s=new StringBuffer();//调用append方法
        int n=0;
        while((n=r.read())!=-1) {
            if(n=='\r') {
   //如果是空格则跳过
                continue;
            }else if(n=='\n'){
   //如果是换行则返回本行已读字符串
                return s.toString();
            }
            s.append((char)n); 
        }
        if(s.length()>0) {
            return s.toString();
        }

        return null;
    }

    public  void close() throws Exception {
        r.close();
    }
}