实现TCP的网络编程

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实现TCP的网络编程

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package com.atguigu.java1;

import org.junit.Test;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * 实现TCP的网络编程
 * 例子1：客户端发送信息给服务端。服务端将数据显示在控制台上
 *
 * @author liangqichen
 * @create 2021-10-26 9:08
 */
public class TCPTest1 {

    // 客户端
    @Test
    public void client() {
        Socket socket = null;
        OutputStream os = null;
        try {
            // 1. 创建Socket对象，指明服务器端的IP和端口号
            InetAddress inet = InetAddress.getByName("127.0.0.1");
            socket = new Socket(inet, 8899);

            // 2. 获取输出流，用于输出数据
            os = socket.getOutputStream();

            //3. 写出数据
            os.write("你好。我是客户端".getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 4.资源的关闭
            if (os != null) {
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    // 服务端
    @Test
    public void server() {
        ServerSocket ss = null;
        Socket socket = null;
        InputStream is = null;
        ByteArrayOutputStream baos = null;
        try {
            // 1.创建 服务器端的ServerSocket，指明自己的端口号
            ss = new ServerSocket(8899);

            // 2.可以调用accept方法，表示接收来自于客户端的Socket
            socket = ss.accept();

            // 3. 获取输入流
            // 不建议这样写，可能会有乱码
            is = socket.getInputStream();
//        byte[] buffer = new byte[1024];
//        int len;
//        while ((len = is.read(buffer)) != -1){
//            String str = new String(buffer,0,len);
//            System.out.print(str);
//        }

            // 4. 读取输入流当中的数据
            baos = new ByteArrayOutputStream();
            byte[] buffer = new byte[5];
            int len;
            while ((len = is.read(buffer)) != -1) {
                baos.write(buffer, 0, len);
            }
            System.out.println(baos.toString());

            System.out.println("收到了来自于"+socket.getInetAddress().getHostAddress()+"的数据");

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 5. 关闭资源
            if (baos != null){
                try {
                    baos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (is != null){
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (socket != null){
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (ss != null){
                try {
                    ss.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}