Java学习之路（六十）| （接上文五十九）TCP网络编程

各自努力，最高处见！加油！

• • socket TCP 网络上传图片
  • • 服务器端代码
    • 客户端代码
    • 工具类文件代码
  • netstat指令

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class FileUploadingServer {
    public static void main(String[] args) throws IOException {
        byte[] buf=new byte[1024];
        int readLen=0;
        String filePath="D:\Java_code\InternetLearn\src\library.jpg";
        FileOutputStream fileOutputStream = new FileOutputStream(filePath);
        ServerSocket serverSocket=new ServerSocket(8888);
        System.out.println("服务端，在8888端口监听，等待连接。。。。");



        Socket socket = serverSocket.accept();
        InputStream inputStream = socket.getInputStream();
        while ((readLen=inputStream.read(buf))!=-1)
        {
            fileOutputStream.write(buf,0,readLen);
        }

        System.out.println("服务器接收到图片！发送已接受指令给客户端！");

        OutputStream outputStream = socket.getOutputStream();
        outputStream.write("收到图片".getBytes());


        inputStream.close();
        fileOutputStream.close();
        outputStream.close();
        socket.close();
    }
}

import java.io.*;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class uploadingClient {
    public static void main(String[] args) throws Exception {
        //客户端读取本地的文件，传入输入流中
        String filePath="E:\library.jpg";
        BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(filePath));//为什么要这一步？
        byte[] bytes = StreamUtils.streamToByteArray(bufferedInputStream);//调用题目所给的库，将输入流中的数据转换成字节数组。

        Socket socket = new Socket(InetAddress.getLocalHost(),8888);//连接到本机的8888端口
        OutputStream outputStream = socket.getOutputStream();//获取到一个字节流
        outputStream.write(bytes);
        socket.shutdownOutput();
        System.out.println("客户端文件发送完毕，准备接收服务器端反馈！");

        byte[] readBytes=new byte[1024];
        InputStream inputStream = socket.getInputStream();
        String s = StreamUtils.streamToString(inputStream);
        System.out.println("服务器端回复："+s);


        bufferedInputStream.close();
        outputStream.close();
        inputStream.close();
        socket.close();
    }
}

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;


public class StreamUtils {
	
	public static byte[] streamToByteArray(InputStream is) throws Exception{
		ByteArrayOutputStream bos = new ByteArrayOutputStream();//创建输出流对象
		byte[] b = new byte[1024];
		int len;
		while((len=is.read(b))!=-1){
			bos.write(b, 0, len);	
		}
		byte[] array = bos.toByteArray();
		bos.close();
		return array;
	}
	
	
	public static String streamToString(InputStream is) throws Exception{
		BufferedReader reader = new BufferedReader(new InputStreamReader(is));
		StringBuilder builder= new StringBuilder();
		String line;
		while((line=reader.readLine())!=null){ //当读取到 null时，就表示结束
			builder.append(line+"rn");
		}
		return builder.toString();
		
	}
}

1. netstat-an可以查看当前主机网络情况，包括端口监听情况和网络连接情况
2. netstat-an | more可以分页显示
3. 要求在dos控制台下运行（win键+R快捷键，输入cmd命令行）

外部地址：连接该端口的外部程序ip地址。
状态：LISTENING监听中，ESTABLISHED（established）已连接
Ctrl+C退出