我需要帮助使用websockets将ESP8266连接到本地Java服务器

问题描述 投票:1回答:1

我下载了一台在我的PC上运行的简单的Java websocket echo服务器(Windows 10)。该应用程序在本地Tomcat服务器上运行(我的PC的IP地址是192.168.178.10)。

要在浏览器中启动应用程序,使用的命令是:

http://localhost:8080/echochamber/

如果我通过浏览器连接它,一切正常。但是,如果我使用NodeMCU(ESP8266),它将拒绝连接。我尝试了一个不同的外部网站:

echo.websocket.org

NodeMCU表现完美无瑕。所以我的第一个猜测是我以错误的方式连接到我的本地服务器。但我现在有点迷失了。为什么我无法连接到本地运行的服务器,而是轻松连接到外部服务器?我哪里弄错了?

提前致谢。

Java Web服务器代码

一节课:

package echochamber;

import java.io.IOException;

import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

/** 
 * @ServerEndpoint gives the relative name for the end point
 * This will be accessed via ws://localhost:8080/EchoChamber/echo
 * Where "localhost" is the address of the host,
 * "EchoChamber" is the name of the package
 * and "echo" is the address to access this class from the server
 */
@ServerEndpoint("/echo") 
public class EchoServer {
    /**
     * @OnOpen allows us to intercept the creation of a new session.
     * The session class allows us to send data to the user.
     * In the method onOpen, we'll let the user know that the handshake was 
     * successful.
     */

    @OnOpen
    public void onOpen(Session session){
        System.out.println(session.getId() + " has opened a connection"); 
        try {
            session.getBasicRemote().sendText("Connection Established");
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

    /**
     * When a user sends a message to the server, this method will intercept the message
     * and allow us to react to it. For now the message is read as a String.
     */
    @OnMessage
    public void onMessage(String message, Session session){
        System.out.println("Message from " + session.getId() + ": " + message);
        try {
            session.getBasicRemote().sendText(message);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

    /**
     * The user closes the connection.
     * 
     * Note: you can't send messages to the client from this method
     */
    @OnClose
    public void onClose(Session session){
        System.out.println("Session " +session.getId()+" has ended");
    }
}

和一个html文件:

<!DOCTYPE html>

<html>
    <head>
        <title>Echo Chamber</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width">
    </head>
    <body>

        <div>
            <input type="text" id="messageinput"/>
        </div>
        <div>
            <button type="button" onclick="openSocket();" >Open</button>
            <button type="button" onclick="send();" >Send</button>
            <button type="button" onclick="closeSocket();" >Close</button>
        </div>
        <!-- Server responses get written here -->
        <div id="messages"></div>

        <!-- Script to utilise the WebSocket -->
        <script type="text/javascript">

            var webSocket;
            var messages = document.getElementById("messages");


            function openSocket(){
                // Ensures only one connection is open at a time
                if(webSocket !== undefined && webSocket.readyState !== WebSocket.CLOSED){
                   writeResponse("WebSocket is already opened.");
                    return;
                }
                // Create a new instance of the websocket
                webSocket = new WebSocket("ws://localhost:8080/echochamber/echo");

                /**
                 * Binds functions to the listeners for the websocket.
                 */
                webSocket.onopen = function(event){
                    // For reasons I can't determine, onopen gets called twice
                    // and the first time event.data is undefined.
                    // Leave a comment if you know the answer.
                    if(event.data === undefined)
                        return;

                    writeResponse(event.data);
                };

                webSocket.onmessage = function(event){
                    writeResponse(event.data);
                };

                webSocket.onclose = function(event){
                    writeResponse("Connection closed");
                };
            }

            /**
             * Sends the value of the text input to the server
             */
            function send(){
                var text = document.getElementById("messageinput").value;
                webSocket.send(text);
            }

            function closeSocket(){
                webSocket.close();
            }

            function writeResponse(text){
                messages.innerHTML += "<br/>" + text;
            }

        </script>

    </body>
</html>

在nodeMCU上,我使用的代码如下:

/*
 * WebSocketClient.ino
 *
 *  Created on: 24.05.2015
 *
 */

#include <Arduino.h>

#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>

#include <WebSocketsClient.h>

#include <Hash.h>

char SSID[]        = "********";
char PASSWORD[]    = "********";

ESP8266WiFiMulti WiFiMulti;
WebSocketsClient webSocket;

#define USE_SERIAL Serial
#define VERIFY                    // if defined goes to echo.websocket.org

void webSocketEvent(WStype_t type, uint8_t * payload, size_t length) {
    char message[100];
    switch (type) {

    case WStype_DISCONNECTED:
        USE_SERIAL.printf("[WSc] Disconnected!\n");
        break;

    case WStype_CONNECTED: {
        USE_SERIAL.printf("[WSc] Connected to url: %s\n", payload);

        // send message to server when Connected
        webSocket.sendTXT("Connected");
    }
        break;
    case WStype_TEXT:
        USE_SERIAL.printf("[WSc] get text: %s\n", payload);

        //send message to server
        sprintf(message, "millis count = %d", millis());
        webSocket.sendTXT(message);
        delay(1000);
        break;
    case WStype_BIN:
        USE_SERIAL.printf("[WSc] get binary length: %u\n", length);
        hexdump(payload, length);

        // send data to server
        // webSocket.sendBIN(payload, length);
        break;
    }

}

void setup() {

    // Serial setup
    //USE_SERIAL.begin(921600);
    USE_SERIAL.begin(115200);

    // output all debug info
    USE_SERIAL.setDebugOutput(true);
    for (uint8_t t = 4; t > 0; t--) {
        USE_SERIAL.printf("[SETUP] BOOT WAIT %d...\n", t);
        USE_SERIAL.flush();
        delay(1000);
    }

    // connect to my local WiFi gateway
    WiFiMulti.addAP(SSID, PASSWORD);

    // WiFi.disconnect();
    while (WiFiMulti.run() != WL_CONNECTED) {
        delay(100);
    }

    // server address, port and URL
#ifdef VERIFY
    webSocket.begin("echo.websocket.org", 80, "/");
#else
    webSocket.begin("192.168.178.10", 80, "/echochamber");
#endif

    // initialte our event handler
    webSocket.onEvent(webSocketEvent);

    // use HTTP Basic Authorization this is optional remove if not needed
    // webSocket.setAuthorization("user", "Password");

    // try ever 5000 again if connection has failed
    webSocket.setReconnectInterval(5000);
    webSocket.
}

void loop() {
    webSocket.loop();
}

如果我连接到echo.websocket.org,这是输出:

scandone
state: 0 -> 2 (b0)
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0
aid 2
cnt 

connected with verelec_1, channel 1
dhcp client start...
[SETUP] BOOT WAIT 3...
[SETUP] BOOT WAIT 2...
[SETUP] BOOT WAIT 1...
ip:192.168.178.16,mask:255.255.255.0,gw:192.168.178.1
[WSc] Connected to url: /
[WSc] get text: Connected
[WSc] get text: millis count = 5363
[WSc] get text: millis count = 6480
[WSc] get text: millis count = 7602
[WSc] get text: millis count = 8729
[WSc] get text: millis count = 9854
[WSc] get text: millis count = 10968
[WSc] get text: millis count = 12096
[WSc] get text: millis count = 13243
[WSc] get text: millis count = 14369
[WSc] get text: millis count = 15905
[WSc] get text: millis count = 17021
[WSc] get text: millis count = 18135
[WSc] get text: millis count = 19251
[WSc] get text: millis count = 20365
[WSc] get text: millis count = 21482
[WSc] get text: millis count = 22597
[WSc] get text: millis count = 23712
[WSc] get text: millis count = 24828
[WSc] get text: millis count = 25945
[WSc] get text: millis count = 27059
[WSc] get text: millis count = 28173
[WSc] get text: millis count = 29313
[WSc] get text: millis count = 30427
[WSc] get text: millis count = 31545
[WSc] get text: millis count = 32661
java spring websocket server nodemcu
1个回答
0
投票

解决方案是将端口更改为8080,它工作正常

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