NIO组件之channel

package com.example.demo;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

/**
 * Created by Administrator on 2019/9/22.
 */
public class NioChannelTest {
    public static void main(String[] args) {
        fileChannelCopyFile();
    }
    public static void fileChannelCopyFile(){
        File srcFile=new File("srcFile.txt");
        File destFile=new File("destFile.txt");

        try{
            if(!destFile.exists()) destFile.createNewFile();
        }catch(Exception e){}

        FileInputStream fis=null;
        FileOutputStream fos=null;
        FileChannel inChannel=null;
        FileChannel outChannel=null;
        try{
            fis=new FileInputStream(srcFile);
            fos=new FileOutputStream(destFile);
　　　　　　　　//通道的获取
            inChannel=fis.getChannel();
            outChannel=fos.getChannel();

            int length=-1;
            ByteBuffer buf=ByteBuffer.allocate(1024);

            while((length=inChannel.read(buf))!=-1){
                buf.flip();

                int outlength=0;
                //将buf写入到输出通道
                while((outlength=outChannel.write(buf))!=0){
                    System.out.println("the byte-len of being wrote"+outChannel);
                }
                //切换到写入模式，请空buf
                buf.clear();
            }
            //强制刷新到磁盘
            outChannel.force(true);

        }catch (Exception e){}
        finally{
            try {//关闭通道
                outChannel.close();
                fos.close();
                inChannel.close();
                fis.close();
            }catch (Exception e){}
        }
    }
}