socket 伺服器向指定的用戶端發訊息，socket訊息

socket 伺服器向指定的用戶端發訊息，socket訊息
一.需求

需求如題. 當多個用戶端串連伺服器時,伺服器如何給指定的用戶端發送訊息.

二.解決方案

核心思想: 在伺服器端,需儲存不同用戶端的socket列表及用戶端相關資訊.
socket含有發送方和接收方的ip和連接埠號碼,所以通過socket就能向指定的用戶端發送訊息.

經查閱資料,得到如下解決方案:

三.實踐

說明:採用第一種解決方案,類比伺服器向指定的用戶端發送訊息.

服務端迴圈監聽,第一個伺服器進來,向其發送其自身序號,第二個進來,遍曆socke列表,向列表中的每一個用戶端發送其對應的序號,從而達到伺服器向指定用戶端發送訊息的功能.
伺服器端

package server;import java.io.*;import java.net.*;import java.util.HashMap;/** * 主函數,實現伺服器向指定用戶端發送訊息的功能. * 用戶端用python書寫 * @author dingding * */public class Run {    private final static int PORT = 30000;    public static HashMap<String, Socket> socketList = new HashMap<>();    public static String channelToken;  //socket 令牌    private static BufferedReader bufferedReader;    public static void main(String[] args) {        try {            ServerSocket server =  new ServerSocket(PORT);            System.out.println("server is listenning...");            while(true){//不斷迴圈隨時等待新的用戶端接入伺服器                Socket clientSocket = server.accept();                bufferedReader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));                channelToken = bufferedReader.readLine();                socketList.put(channelToken,clientSocket);   //儲存會話ID和socket                //System.out.println(socketList.get(channelToken));                //System.out.println(socketList);                new ServerThread(clientSocket,socketList);            }        } catch (IOException e) {            e.printStackTrace();        }    }}

package server;import java.io.*;import java.net.*;import java.util.*;public class ServerThread extends Thread{    private Socket client;    private PrintWriter out;    private  HashMap<String, Socket> clientList = new HashMap<>();    public ServerThread(Socket socket,HashMap<String, Socket> socketList) throws IOException{        super();        client = socket;        clientList = socketList;        start();    }    @Override    public void run(){        Socket socket;        System.out.println("Client: "+getName()+" come in...");        //每當用戶端串連上,就向相應的用戶端進行回應        Iterator<HashMap.Entry<String, Socket>> entries = clientList.entrySet().iterator();         while (entries.hasNext()){            HashMap.Entry<String, Socket> entry = entries.next();             System.out.println(entry.getKey());            if (!String.valueOf(entry.getKey()).equals("")) {                System.out.println(entry.getValue());                System.out.println("-------------");                socket = entry.getValue();                if (socket!=null) {                    try {                        out = new PrintWriter(socket.getOutputStream());  //回複client的ID                        out.println(entry.getKey());                        out.flush();                    } catch (IOException e) {                        e.printStackTrace();                    }                }            }        }    }}

兩個用戶端
用兩個python用戶端來類比情境.

#coding = utf-8import socketimport threadingHOST = "localhost"PORT = 30000sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)sock.connect((HOST, PORT))  def test():    socketID = 'I am 111'        sock.sendall((socketID+'\r').encode())    while True:        data = sock.recv(1024).decode()        print('from line: '+data)    sock.close()if __name__ == '__main__':    test()

#coding = utf-8import socketimport threadingHOST = "localhost"PORT = 30000sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)sock.connect((HOST, PORT))def test():    socketID = 'I am 000'        sock.sendall((socketID+'\r').encode())    while True:        data = sock.recv(1024).decode()        print('from line: '+data)    sock.close()if __name__ == '__main__':    test()

四.總結

socket 伺服器向指定的用戶端發訊息,網上給的資源不多,大多是關於伺服器群發. 這裡給出了具體解決方案,並通過執行個體證實了該方案的可行性.

有時看的資料越多,越不明白.這並總是好事.
這個時候就需要靜下來理理思路,然後針對具體的解決方案,編程實現.
實踐才是檢驗真理的唯一標準,設計代碼的時候你就離成功又近了一步.

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