网络I/o编程模型4 NIo之chanel通道实现文件复制

1.代码

package com.ljf.netty.nio;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;


public class WriteToLocalDemo {
    public static void main(String[] args) throws IOException {
        String str="hello,中国";
        String dstPath="d:/liu.txt";
        //创建一个输出流
        FileOutputStream fileOutputStream=new FileOutputStream(dstPath);
        //通过fileOutputStream获取对应的FileChannel
        FileChannel fileChannel=fileOutputStream.getChannel();
        //创建一个缓冲区 ByteBuffer
        ByteBuffer byteBuffer=ByteBuffer.allocate(1024);
        //将str内容放到缓存中
        byteBuffer.put(str.getBytes());
        //对bypteBuffer进行flip
        byteBuffer.flip();
        //将byteBuffer数据写入到fileChannel中
        fileChannel.write(byteBuffer);
        fileChannel.close();

    }
}

2.效果

1.代码

package com.ljf.netty.nio;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;


public class ReadFromLocalDemo {
    public static void main(String[] args) throws IOException {
        File file=new File("d:/liu.txt");
        //创建文件的输入流
        FileInputStream fileInputStream=new FileInputStream(file);
        //通过fileinputstream 获取对应的filechannel
        FileChannel fileChannel=fileInputStream.getChannel();
        //创建缓存区
        ByteBuffer byteBuffer=ByteBuffer.allocate((int)file.length());
        //将通道的数据读入到Buffer
        fileChannel.read(byteBuffer);
        System.out.println(new String(byteBuffer.array()));
        fileChannel.close();
    }
}

2.结果

1.代码

package com.ljf.netty.nio;

import java.io.*;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;


public class FileChannel01 {
    public static void main(String[] args) throws IOException {
        //读
        FileInputStream fileInputStream=new FileInputStream("d:/liu.txt");
        FileChannel fileChannel01=fileInputStream.getChannel();
        //写
        FileOutputStream fileOutputStream=new FileOutputStream("d:/liu2.txt");
        FileChannel fileChanne02=fileOutputStream.getChannel();
        ByteBuffer byteBuffer=ByteBuffer.allocate(1024);
        //循环
        while(true){
            //清空buffer，防止上一次存储的数据存储，
            byteBuffer.clear();
           int read= fileChannel01.read(byteBuffer);
           if(read==-1){
            System.out.println("已经读完，退出");
            break;
           }
           //将buffer中的数据写入到filechannel02中
            byteBuffer.flip();
           fileChanne02.write(byteBuffer);

        }
        fileChannel01.close();
        fileChanne02.close();
        System.out.println("结束......");
    }
}

2.结果

1.代码

package com.ljf.netty.nio;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;


public class TransferFileDemo {
    public static void main(String[] args) throws IOException {
        FileInputStream   fileInputStream=new FileInputStream("d:/liu.txt");
        FileOutputStream  fileOutputStream=new FileOutputStream("d:/liu3.txt");
        //获取各个流对应的filechannel
        FileChannel sourceCh=fileInputStream.getChannel();
        FileChannel destCh=fileOutputStream.getChannel();
        //使用transferFrom完成复制
        destCh.transferFrom(sourceCh,0,sourceCh.size());
        //关闭通道
        sourceCh.close();
        destCh.close();
        fileInputStream.close();
        fileOutputStream.close();




    }
}

2.结果

//Scattering:将数据写入到buffer时，可以采用buffer数组，依次写入【分散】
//Gathering: 从buffer读取数据时，可以采用buffer数组，依次读

1.代码

package com.ljf.netty.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;


public class BacthCopy {
    public static void main(String[] args) throws IOException {
        //Scattering:将数据写入到buffer时，可以采用buffer数组，依次写入【分散】
        //Gathering: 从buffer读取数据时，可以采用buffer数组，依次读
        //使用 ServerSocketChannel和socketChannel网络
        ServerSocketChannel  serverSocketChannel=ServerSocketChannel.open();
        InetSocketAddress inetSocketAddress=new InetSocketAddress(7000);
        //绑定端口到socket，并启动
        serverSocketChannel.socket().bind(inetSocketAddress);
        //创建buffer数组
        ByteBuffer[] byteBuffers=new ByteBuffer[2];
        byteBuffers[0]=ByteBuffer.allocate(5);
        byteBuffers[1]=ByteBuffer.allocate(3);
        //等客户端连接
        SocketChannel socketChannel=serverSocketChannel.accept();
        int messageLenght=8;
        //循环读取
        while(true){
            int byteRead=0;
            while(byteRead "位置:"+bb.position()+" limit:"+bb.limit()).forEach(System.out::println);
                List dataList=Arrays.asList(byteBuffers);
                

            }
            //将所有的buffer进行flip
            Arrays.asList(byteBuffers).forEach(buffer->buffer.flip());
            //将数据读出，显示到客户端
            long byteWirte=0;
            while(byteWirte{buffer.clear();});
            System.out.println("byteRead:"+byteRead+" bytewrite:"+byteWirte+"messagelength:"+messageLenght);
        }
    }
}

2.测试结果

cmd窗口，输入： telnet localhost 7000

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