Netty NIO ByteBuffer 简单实验

1.概要

准备学一下Netty,先从NIO的三大组件开始。先ByteBuffer

2.代码

2.1 主函数 

package com.xjc.springcloundtest;
 
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
 
public class Main {
    public static void main(String[] args) throws IOException {
        FileChannel channel = new FileInputStream("4.txt").getChannel();
        ByteBuffer byteBuffer = ByteBuffer.allocate(10);
        while (true){
            int len = channel.read(byteBuffer);
            System.out.println("读取的字节数:"+len);
            if(len==-1){
                break;
            }
            byteBuffer.flip();
            while (byteBuffer.hasRemaining()){
                byte b = byteBuffer.get();
                System.out.println((char)b);
            }
            byteBuffer.clear();
        }
 
        System.out.println("Hello world!");
    }
}

2.2 准备的文件（4.txt）

123456789abc

3.运行结果

C:\Users\ThinkPad\.jdks\openjdk-21.0.2\bin\java.exe "-javaagent:D:\Program Files\JetBrains\IntelliJ IDEA 2023.3.2\lib\idea_rt.jar=51792:D:\Program Files\JetBrains\IntelliJ IDEA 2023.3.2\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\Users\ThinkPad\IdeaProjects\untitled12\target\classes com.xjc.springcloundtest.Main
读取的字节数:10
1
2
3
4
5
6
7
8
9
a
读取的字节数:2
b
c
读取的字节数:-1
Hello world!
 
Process finished with exit code 0