维护Arduino和Java程序之间的通信

我在学校里有一个项目，包括一辆可以通过WiFi控制的遥控车。 它工作正常几秒钟，但它只是停止连接并尝试再次重新连接。 事实是，如果我正在制造依赖于不稳定连接的汽车，它可能会导致事故。 无论是对自己还是对个人。

也许我做错了什么？ 我的问题是，我如何始终保持该连接的活动状态？ 到目前为止，这是我的程序：

Arduino客户：

#include  #include  int status = WL_IDLE_STATUS; char ssid[] = "mynet"; char pass[] = "password"; IPAddress remoteIp(192,168,80,165); int port = 37899; String message = ""; WiFiClient client; void setup() { // start the serial for debugging Serial.begin(9600); pinMode(9, OUTPUT); digitalWrite(9, LOW); //check if the wifi shield is present if(WiFi.status() == WL_NO_SHIELD){ Serial.println("WiFi shield not present! Press reset to try again."); while(true); //stops the program } connectWiFi(); printWifiStatus(); connectClient(3); } void loop(){ if(client){ if(client.available()){ char c = client.read(); if(c != '\n'){ message += c; } else{ Serial.println("Received message: "+message); checkMessage(); sendMessage(message); message = ""; } } } } void printWifiStatus() { // print the SSID of the network you're attached to: Serial.print("SSID: "); Serial.println(WiFi.SSID()); // print your WiFi shield's IP address: IPAddress ip = WiFi.localIP(); Serial.print("IP Address: "); Serial.println(ip); } void connectWiFi(){ if( status != WL_CONNECTED){ while(status != WL_CONNECTED){ Serial.print("Attempting connection to network..."); status = WiFi.begin(ssid, pass); delay(3000); if(status == WL_CONNECTED){ Serial.println(" SUCSESS"); } else{ Serial.println(" FAILED"); delay(3000); connectWiFi(); } } } } void connectClient(int retries){ //Attempt connection to server if(retries  0){ Serial.println("FAILED"); connectClient(retries - 1); } } void checkMessage(){ if(message == "on"){ digitalWrite(9, HIGH); } if(message == "off"){ digitalWrite(9, LOW); } } void sendMessage(String toSend){ if(client){ client.println(toSend+'\n'); client.flush(); Serial.println("Sendt message: "+toSend); } else{ Serial.println("Could not send message; Not connected."); } } 

Java服务器：

 import java.io.*; import java.net.*; import java.awt.*; import java.awt.event.*; import javax.swing.*; public class Car_Client extends JFrame { private JTextField userText; private JTextArea chatWindow; private static final int serverPort = 37899; private ServerSocket server; private Socket connection; private BufferedWriter output; private BufferedReader input; private String message = ""; public Car_Client() { userText = new JTextField(); userText.setEditable(false); userText.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent event) { sendMessage(event.getActionCommand()); userText.setText(""); } } ); add(userText, BorderLayout.NORTH); chatWindow = new JTextArea(); add(new JScrollPane(chatWindow), BorderLayout.CENTER); setSize(400, 300); setVisible(true); } public void startRunning() { try { server = new ServerSocket(serverPort, 100); while (true) { try { waitForConnection(); setupStreams(); whileConnected(); } catch (EOFException eofException) { showMessage("Client terminated connection"); } catch (IOException ioException) { showMessage("Could not connect..."); } finally { closeStreams(); } } } catch (IOException ioException) { ioException.printStackTrace(); } } private void waitForConnection() throws IOException { showMessage("Waiting for someone to connect..."); connection = server.accept(); //once someone asks to connect, it accepts the connection to the socket this gets repeated fast showMessage("Now connected to " + connection.getInetAddress().getHostName()); //shows IP adress of client } private void setupStreams() throws IOException { showMessage("creating streams..."); output = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream())); output.flush(); input = new BufferedReader(new InputStreamReader(connection.getInputStream())); showMessage("Streams are setup!"); } private void whileConnected() throws IOException { ableToType(true); //makes the user able to type do { char x = (char) input.read(); while (x != '\n') { message += x; x = (char) input.read(); } showMessage(message); message = ""; } while (!message.equals("END")); //if the user has not disconnected, by sending "END" } private void closeStreams() { ableToType(false); showMessage("Closing streams..."); try { output.close(); input.close(); connection.close(); } catch (IOException ex) { ex.printStackTrace(); } } private void sendMessage(String message) { try { output.write(message + '\n'); output.flush(); showMessage("Sent: " + message); } catch (IOException ex) { chatWindow.append("\nSomething messed up whilst sending messages..."); } } private void showMessage(final String message) { SwingUtilities.invokeLater( new Runnable() { public void run() { chatWindow.append('\n' + message); } } ); } private void ableToType(final boolean tof) { SwingUtilities.invokeLater( new Runnable() { public void run() { userText.setEditable(tof); } } ); } } 

干杯!
-kad

Answer 1

我解决了它，我做了它，以便Arduino每15秒向Java程序发送数据。 所有这些都是Arduino计划的一些方面：

变量：

 long lastSendt; 

循环function：

 void loop(){ if(client){ if(millis() >= (lastSendt + 15000)){ sendCharacter('*') } if(client.available()){ char c = client.read(); if(c != '\n'){ message += c; } else{ Serial.println("Received message: "+message); checkMessage(); sendMessage(message); message = ""; } } } } 

sendCharacter函数：

 void sendCharacter(char toSend){ if(client){ client.println(toSend){ lastSendt = millis(); }else{ Serial.println("Could not send character!"); } }