ESP8266 创建TCP连接

TCP Client

使用WiFiClient类可以实现TCP Client

基本方法

• 连接Server，connect

WiFiClient client;
client.connect(host, port)

• 检测客户端是否存在数据流

client.available()

• 读取客户端的一个字符

client.read();

• 检查连接状态

client.connected()

使用网络串口工具，创建一个tcp server供该设备进行连接，可实现每十秒向服务端发送字符串"Hello from Arduino!"，并且能够接受服务端发送的字符串并显示到串口

缺点：如果发送的间隔过短，可能出现同时输出两次字符串的情况

示例代码

#include <ESP8266WiFi.h>
#include <WiFiClient.h>const char* ssid = "TP-LINK_3DF2";           // 替换为你的WiFi网络名称
const char* password = "123454321";          // 替换为你的WiFi网络密码
const char* host = "192.168.0.111";          // 替换为你的服务器地址
const uint16_t port = 8266;                  // 服务器端口号WiFiClient client;
unsigned long previousMillis = 0;
const long interval = 10000;                 // 发送间隔时间为10秒void setup() {Serial.begin(115200);// 连接到WiFi网络Serial.println("Connecting to WiFi...");WiFi.begin(ssid, password);while (WiFi.status() != WL_CONNECTED) {delay(1000);Serial.println("Connecting...");}Serial.println("Connected to WiFi!");// 连接到服务器if (!client.connect(host, port)) {Serial.println("Connection failed.");return;}Serial.println("Connected to server!");
}void loop() {// 实时接收服务器发送的数据String tmpStr = "";while (client.available()) {char c = client.read();tmpStr.concat(c); }if(tmpStr.length() > 0){Serial.println(tmpStr);tmpStr = "";}// 获取当前时间unsigned long currentMillis = millis();// 检查是否已经过去了指定的间隔时间if (currentMillis - previousMillis >= interval) {previousMillis = currentMillis;// 发送数据到服务器sendDataToServer();}// 只在发送或接收失败时检查连接状态if (!client.connected()) {reconnectToServer();}
}void sendDataToServer() {String message = "Hello from Arduino!";if (client.connected()) {client.println(message);Serial.print("Sent to server: ");Serial.println(message);} else {Serial.println("Failed to send, not connected to server.");}
}void reconnectToServer() {Serial.println("Disconnected from server.");client.stop();// 尝试重新连接if (!client.connect(host, port)) {Serial.println("Reconnection failed.");delay(5000);  // 等待5秒后再尝试重新连接} else {Serial.println("Reconnected to server!");}
}

TCP Server