IO流练习：模拟一个带行号的缓冲区对象

绝地灬酷狼 2021-09-19 16:04 277阅读 0赞

### 【需求】：模拟一个带行号的缓冲区对象 ###

读取的内容Demo.java：

> class Demo   
> \{  
>     public static void main(String\[\] args)   
>     \{  
>         System.out.println('h');  
>         System.out.println("=================");  
>         System.out.println("goodgoodstudy");  
>         System.out.println("Hello World!");  
>     \}  
> \}

### 【代码】： ###

import java.io.*;
    class MyLineNumberReader 
    {
    	private int lineNumber=0;
    	private Reader r;
    	MyLineNumberReader(Reader r){
    		this.r=r;
    	}
    	public void setLineNumber(int lineNumber){
    		this.lineNumber=lineNumber;
    	}
    	public int getLineNumber(){
    		return lineNumber;
    	}
    	public String myReadLine() throws IOException{
    		lineNumber++;
    		StringBuilder sb=new StringBuilder();
    		int ch=0;
    		while((ch=r.read())!=-1){
    			if (ch=='\r') continue;
    			else 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();
    	}
    }
    class MyLineNumberReaderDemo{
    	public static void main(String[] args) throws IOException
    	{
    		FileReader fr=new FileReader("Demo.java");
    		MyLineNumberReader mlnr=new MyLineNumberReader(fr);
    		String line=null;
    		mlnr.setLineNumber(0);
    		while((line=mlnr.myReadLine())!=null){
    			System.out.println(mlnr.getLineNumber()+":"+line);
    		}
    		fr.close();
    	}
    }

### 【截图】： ###

### ![20190529184628353.png][] ###

[20190529184628353.png]: /images/20210811/c32937abd0b944a997d818e17847f97b.png