package com.charjay.nio.buffer.file;

import java.io.FileInputStream;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class BufferProgram {  
    public static void main(String args[]) throws Exception {  
    	
    	//这用用的是文件IO处理
        FileInputStream fin = new FileInputStream("E:/io.txt");
        //创建文件的操作管道
        FileChannel fc = fin.getChannel();
        
        //分配一个10个大小缓冲区，说白了就是分配一个10个大小的byte数组
        ByteBuffer buffer = ByteBuffer.allocate(10);  
        output("初始化", buffer);
        
        //先读一下
        fc.read(buffer);  
        output("调用read()", buffer);  
  
        //准备操作之前，先锁定操作范围
        buffer.flip();  
        output("调用flip()", buffer);  
  
        //判断有没有可读数据
        while (buffer.remaining() > 0) {  
            byte b = buffer.get();
//            String data=new String(b,"");
             System.out.print("data="+((char)b));
        }  
        output("调用get()", buffer);  
  
        //可以理解为解锁
        buffer.clear();  
        output("调用clear()", buffer);  
  
        //最后把管道关闭
        fin.close();  
    }  
  
    
    //把这个缓冲里面实时状态给答应出来
    public static void output(String step, Buffer buffer) {  
        System.out.println(step + " : "); 
        //容量，数组大小
        System.out.print("capacity: " + buffer.capacity() + ", ");
        //当前操作数据所在的位置，也可以叫做游标
        System.out.print("position: " + buffer.position() + ", ");
        //锁定值，flip，数据操作范围索引只能在position - limit 之间
        System.out.println("limit: " + buffer.limit());  
        System.out.println("=============");
    }  
}