Swift Network.framework Study 20200319 "Receive and Send"

Study

Network.framework Study：Receive and Send

environment

Client：Java、NetBeans Server：Swift、Xcode

Server Source Swift

main.swift

import Foundation
import Network

var receiveANdSend = ReceiveAndSend()
receiveANdSend.startListener()
while receiveANdSend.running {
    sleep(1)
}

ReceiveAndSend.swift

import Foundation
import Network

class ReceiveAndSend {
    public var running = true

    func startListener() {
        let myQueue = DispatchQueue(label: "ExampleNetwork")

        do {
            let nWListener = try NWListener(using: .tcp, on: 7777)
            nWListener.newConnectionHandler = { (newConnection) in
                print("New Connection!!")
                newConnection.start(queue: myQueue)
                self.receive(nWConnection: newConnection)
            }
            nWListener.start(queue: myQueue)
            print("start")
        }
        catch {
            print(error)
        }
    }
    
    func receive(nWConnection:NWConnection) {
        nWConnection.receive(minimumIncompleteLength: 1, maximumLength: 5, completion: { (data, context, flag, error) in
            print("receiveMessage")
            if let data = data {
                let receiveData = [UInt8](data)
                print(receiveData)
                print(flag)
                self.sendMessage(nWConnection)
                if(flag == false) {
                    self.receive(nWConnection: nWConnection)
                }
            }
            else {
                print("receiveMessage data nil")
            }
        })
    }

    func sendMessage(_ connection: NWConnection) {
        let data = "Answer".data(using: .utf8)
        let completion = NWConnection.SendCompletion.contentProcessed { (error: NWError?) in
            print("Response transmission completed")
            self.running = false
        }
        connection.send(content: data, completion: completion)
    }
}

Client Source Java

public class ExampleSendAndReceive {
   public static void main(String[] args) {
        try(Socket socket = new Socket("localhost", 7777);
            PrintWriter printWriter = new PrintWriter(socket.getOutputStream(), true);) {

            Runnable runnable = () -> {
                System.out.println("Receive start");
                try {
                    int data = socket.getInputStream().read();
                    while(data != -1) {
                        System.out.print(data + " ");
                        data = socket.getInputStream().read();
                    }
                    System.out.println("end");
                }
                catch(Exception e) {
                    System.out.println(e);
                }
            };
            Thread thread = new Thread(runnable);
            thread.start();
            
            for(int i = 0; i < 5; i++) {
                printWriter.println("12345");
                Thread.sleep(5000);
            }
        }
        catch(Exception e) {
            System.out.println(e);
        }
    }    
}