Java NIO指的是new IO ,相对OIO,也称non-blocking IO,对应四种基本IO类型中的IO多路复用,主要有有三大核心组件,Channel(管道),Buffer(缓冲区),selector(选择器)

基本操作流程 

allcocate创建实例对象--》put写入数据--》flip切换到读取模式--》get读取数据--》clear切回写入模式

如下注释:

package com.example.demo;

import java.nio.IntBuffer;

/**
 * Created by Administrator on 2019/9/22.
 */
public class NioTest {
    static IntBuffer intBuffer=null;
    public static void main(String[] args) {
        intBuffer=IntBuffer.allocate(20);//默认为写入模式
        print();//创建缓冲区p:l:c 0:20:20 p为position l为limit c为capacity
        put();//插入5个数
        print();//p:l:c  5:20:20 写入模式下写入数据只是改变postition的值
        get(2);//输出两个0
        print();//p:l:c 7:20:20 没有切换模式的情况下,get也变为在末尾添加两个0

        flip();//p:l:c 0:7:20 翻转,切换为读取模式 
        get(4);

        print();//p:l:c 4:7:20
        get(2);
        print();//p:l:c 6:7:20
// intBuffer.rewind() //倒带重读 p:l:c 0:7:20 clear();//p:l:c 0:20:20 切回写入模式,并清空
// compact();//p:l:c 1:20:20 切回写入模式,保留未读取的数据 print();
      }
public static void put(){ for (int i = 0; i < 5; i++) { intBuffer.put(i); } System.out.println("putting data"); } public static void print(){ System.out.println("position=="+intBuffer.position()); System.out.println("limit=="+intBuffer.limit()); System.out.println("capacity=="+intBuffer.capacity()); } public static void flip(){ intBuffer.flip(); System.out.println("flipping"); } public static void clear(){ intBuffer.clear(); System.out.println("clearing the buffer"); } public static void compact(){ intBuffer.compact(); System.out.println("compacting the buffer"); } public static void get(int n){ System.out.println("starting to read"); for (int i = 0; i < n; i++) { System.out.println("read data=="+intBuffer.get()); } System.out.println("ending to read"); } }

输出

position==0
limit==20
capacity==20
putting data
position==5
limit==20
capacity==20
starting to read
read data==0
read data==0
ending to read
position==7
limit==20
capacity==20
flipping
starting to read
read data==0
read data==1
read data==2
read data==3
ending to read
position==4
limit==7
capacity==20
starting to read
read data==4
read data==0
ending to read
position==6
limit==7
capacity==20
clearing the buffer
position==0
limit==20
capacity==20

posted on 2019-09-22 21:31  pu20065226  阅读(192)  评论(0编辑  收藏  举报