TCP

1.服務器綁定端口號啟動服務器歡迎socket。

2. 等待客戶端發(fā)送請求。

3.等到客戶端發(fā)送請求之后，服務器與客戶端重新建立一個socket，但是客戶端的目標端口不變。

java代碼如下

客戶端

客戶端代碼圖解

import java.io.*;
import java.net.*;
class TCPClient {
    public static void main(String argv[]) throws Exception
    {
        String sentence;
        String modifiedSentence;
        BufferedReader inFromUser = new BufferedReader(
                new InputStreamReader(System.in));
        //開一個socket
        Socket clientSocket = new Socket("localhost", 6789);
        DataOutputStream outToServer = new DataOutputStream(
                clientSocket.getOutputStream());
        BufferedReader inFromServer =
                new BufferedReader(new InputStreamReader(
                        clientSocket.getInputStream()));
        sentence = inFromUser.readLine();
        //發(fā)送請求
        outToServer.writeBytes(sentence + '\n');
        //接受響應
        modifiedSentence = inFromServer.readLine();
        System.out.println("FROM SERVER: " +
            modifiedSentence);
        //關(guān)閉客戶端
        clientSocket.close();
    }
}

服務端?

import java.io.*;
import java.net.*;
class TCPServer {

    public static void main(String argv[]) throws Exception
    {
        String clientSentence;
        String capitalizedSentence;
        //開一個socket用做于歡迎socket
        ServerSocket welcomeSocket = new ServerSocket
                (6789);
        while(true) {
            //接受客戶端的請求
            Socket connectionSocket = welcomeSocket.
                    accept();
            BufferedReader inFromClient =
                    new BufferedReader(new InputStreamReader(
                            connectionSocket.getInputStream()));
            DataOutputStream outToClient =
                    new DataOutputStream(
                            connectionSocket.getOutputStream());
            //從客戶端接受到信息
            clientSentence = inFromClient.readLine();
            //改變客戶端發(fā)送的信息
            capitalizedSentence =
                    clientSentence.toUpperCase() + '\n';
            //發(fā)回給客戶端
            outToClient.writeBytes(capitalizedSentence);
        }
    }
}

UDP?

1.udp的客戶端可以比udp的服務端先開啟

2.服務器綁定端口?

java代碼如下：

客戶端?

文章來源地址http://www.zghlxwxcb.cn/news/detail-514540.html

import java.io.*;
import java.net.*;
class UDPClient {
    public static void main(String args[]) throws Exception
    {
        BufferedReader inFromUser =
                new BufferedReader(new InputStreamReader
                        (System.in));
        //為客戶端進程創(chuàng)建了一個門，但沒有在兩個進程之間創(chuàng)建管道
        DatagramSocket clientSocket = new DatagramSocket();
        //調(diào)用DNS查找
        InetAddress IPAddress =
                InetAddress.getByName("localhost");
        byte[] sendData = new byte[1024];
        byte[] receiveData = new byte[1024];
        String sentence = inFromUser.readLine();
        sendData = sentence.getBytes();
        //與TCP發(fā)送流不同，udp是打一個包發(fā)過去，這個就是udp的包
        //這一行構(gòu)造數(shù)據(jù)包sendPacket，客戶機將通過套接字將其彈出到網(wǎng)絡中。
        // 這個包包括包中包含的數(shù)據(jù)、sendData、該數(shù)據(jù)的長度、服務器的IP地址和應用程序的端口號(我們將其設(shè)置為9876)。
        DatagramPacket sendPacket =
                new DatagramPacket(sendData, sendData.length,
                        IPAddress, 9876);
        clientSocket.send(sendPacket);
        //接受服務器響應包
        DatagramPacket receivePacket =
                new DatagramPacket(receiveData,
                        receiveData.length);
        clientSocket.receive(receivePacket);
        //將回復的包中的數(shù)據(jù)拿出來
        String modifiedSentence =
                new String(receivePacket.getData());
        System.out.println("FROM SERVER:" +
            modifiedSentence);
        //關(guān)閉客戶端，釋放資源
        clientSocket.close();
    }
}

?服務器

import java.io.*;
import java.net.*;
public class UDPServer {
    public static void main(String args[]) throws Exception
    {
        DatagramSocket serverSocket = new
                DatagramSocket(9876);
        byte[] receiveData = new byte[1024];
        byte[] sendData = new byte[1024];
        while(true)
        {
            //接受客戶端發(fā)來的請求
            DatagramPacket receivePacket =
                    new DatagramPacket(receiveData,
                            receiveData.length);
            serverSocket.receive(receivePacket);
            //將客戶端的請求的信息轉(zhuǎn)為字符數(shù)組
            String sentence = new String(
                    receivePacket.getData());
            //從請求里拿到客戶端IP地址
            InetAddress IPAddress =
                    receivePacket.getAddress();
            //拿到客戶端端口
            int port = receivePacket.getPort();
            String capitalizedSentence =
                    sentence.toUpperCase();
            sendData = capitalizedSentence.getBytes();
            //將要返回的響應打包，里面需要客戶端的IP地址，客戶端端口
            DatagramPacket sendPacket =
                    new DatagramPacket(sendData,
                            sendData.length, IPAddress, port);
            //服務器發(fā)送響應包
            serverSocket.send(sendPacket);
        }
    }
}

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