ESP8266 Community Forum

How to Create a Java Web (HTTP) Server, and make a 2 way communication with ESP8266 (ESP-01) trough WiFi:
Java WebServer Code:

package test;

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

public class MyTest {

public static void main(String[] args) throws Exception {
HttpServer server = HttpServer.create(new InetSocketAddress(1201), 0);
server.createContext("/VarghaHokmran", new MyHandler());
server.setExecutor(null); // creates a default executor
server.start();
}

static class MyHandler implements HttpHandler {
public void handle(HttpExchange t) throws IOException {

OutputStream os = t.getResponseBody();
// extracting barcode from url
String myVar = t.getRequestURI().toString().substring(14, 18);
//String myVar = t.getRequestURI().toString();
System.out.println("My Variable: " + myVar);
String response = "{myData: \"myText\":\"Like\",\"otherText\":\"Subscribe\"}";
t.sendResponseHeaders(200, response.length());
os.write(response.getBytes());
os.close();
}
}

}



Code for ESP8266:

#include <ESP8266WiFi.h>
#include <ArduinoJson.h>
#include "FS.h"
/*End of BarcodeScanner Settings */
#define PIN_SCE 3 //Pin 3 on LCD
#define PIN_RESET 4 //Pin 4 on LCD
#define PIN_DC 2 //Pin 5 on LCD
#define PIN_SDIN 1 //Pin 6 on LCD
#define PIN_SCLK 0 //Pin 7 on LCD

//The DC pin tells the LCD if we are sending a command or data
#define LCD_COMMAND 0
#define LCD_DATA 1

//You may find a different size screen, but this one is 84 by 48 pixels
#define LCD_X 84
#define LCD_Y 48

//This table contains the hex values that represent pixels
//for a font that is 5 pixels wide and 8 pixels high
static const byte ASCII[][5] = {
{0x00, 0x00, 0x00, 0x00, 0x00} // 20
,{0x00, 0x00, 0x5f, 0x00, 0x00} // 21 !
,{0x00, 0x07, 0x00, 0x07, 0x00} // 22 "
,{0x14, 0x7f, 0x14, 0x7f, 0x14} // 23 #
,{0x24, 0x2a, 0x7f, 0x2a, 0x12} // 24 $
,{0x23, 0x13, 0x08, 0x64, 0x62} // 25 %
,{0x36, 0x49, 0x55, 0x22, 0x50} // 26 &
,{0x00, 0x05, 0x03, 0x00, 0x00} // 27 '
,{0x00, 0x1c, 0x22, 0x41, 0x00} // 28 (
,{0x00, 0x41, 0x22, 0x1c, 0x00} // 29 )
,{0x14, 0x08, 0x3e, 0x08, 0x14} // 2a *
,{0x08, 0x08, 0x3e, 0x08, 0x08} // 2b +
,{0x00, 0x50, 0x30, 0x00, 0x00} // 2c ,
,{0x08, 0x08, 0x08, 0x08, 0x08} // 2d -
,{0x00, 0x60, 0x60, 0x00, 0x00} // 2e .
,{0x20, 0x10, 0x08, 0x04, 0x02} // 2f Slash
,{0x3e, 0x51, 0x49, 0x45, 0x3e} // 30 0
,{0x00, 0x42, 0x7f, 0x40, 0x00} // 31 1
,{0x42, 0x61, 0x51, 0x49, 0x46} // 32 2
,{0x21, 0x41, 0x45, 0x4b, 0x31} // 33 3
,{0x18, 0x14, 0x12, 0x7f, 0x10} // 34 4
,{0x27, 0x45, 0x45, 0x45, 0x39} // 35 5
,{0x3c, 0x4a, 0x49, 0x49, 0x30} // 36 6
,{0x01, 0x71, 0x09, 0x05, 0x03} // 37 7
,{0x36, 0x49, 0x49, 0x49, 0x36} // 38 8
,{0x06, 0x49, 0x49, 0x29, 0x1e} // 39 9
,{0x00, 0x36, 0x36, 0x00, 0x00} // 3a :
,{0x00, 0x56, 0x36, 0x00, 0x00} // 3b ;
,{0x08, 0x14, 0x22, 0x41, 0x00} // 3c <
,{0x14, 0x14, 0x14, 0x14, 0x14} // 3d =
,{0x00, 0x41, 0x22, 0x14, 0x08} // 3e >
,{0x02, 0x01, 0x51, 0x09, 0x06} // 3f ?
,{0x32, 0x49, 0x79, 0x41, 0x3e} // 40 @
,{0x7e, 0x11, 0x11, 0x11, 0x7e} // 41 A
,{0x7f, 0x49, 0x49, 0x49, 0x36} // 42 B
,{0x3e, 0x41, 0x41, 0x41, 0x22} // 43 C
,{0x7f, 0x41, 0x41, 0x22, 0x1c} // 44 D
,{0x7f, 0x49, 0x49, 0x49, 0x41} // 45 E
,{0x7f, 0x09, 0x09, 0x09, 0x01} // 46 F
,{0x3e, 0x41, 0x49, 0x49, 0x7a} // 47 G
,{0x7f, 0x08, 0x08, 0x08, 0x7f} // 48 H
,{0x00, 0x41, 0x7f, 0x41, 0x00} // 49 I
,{0x20, 0x40, 0x41, 0x3f, 0x01} // 4a J
,{0x7f, 0x08, 0x14, 0x22, 0x41} // 4b K
,{0x7f, 0x40, 0x40, 0x40, 0x40} // 4c L
,{0x7f, 0x02, 0x0c, 0x02, 0x7f} // 4d M
,{0x7f, 0x04, 0x08, 0x10, 0x7f} // 4e N
,{0x3e, 0x41, 0x41, 0x41, 0x3e} // 4f O
,{0x7f, 0x09, 0x09, 0x09, 0x06} // 50 P
,{0x3e, 0x41, 0x51, 0x21, 0x5e} // 51 Q
,{0x7f, 0x09, 0x19, 0x29, 0x46} // 52 R
,{0x46, 0x49, 0x49, 0x49, 0x31} // 53 S
,{0x01, 0x01, 0x7f, 0x01, 0x01} // 54 T
,{0x3f, 0x40, 0x40, 0x40, 0x3f} // 55 U
,{0x1f, 0x20, 0x40, 0x20, 0x1f} // 56 V
,{0x3f, 0x40, 0x38, 0x40, 0x3f} // 57 W
,{0x63, 0x14, 0x08, 0x14, 0x63} // 58 X
,{0x07, 0x08, 0x70, 0x08, 0x07} // 59 Y
,{0x61, 0x51, 0x49, 0x45, 0x43} // 5a Z
,{0x00, 0x7f, 0x41, 0x41, 0x00} // 5b [
,{0x02, 0x04, 0x08, 0x10, 0x20} // 5c Backslash
,{0x00, 0x41, 0x41, 0x7f, 0x00} // 5d ]
,{0x04, 0x02, 0x01, 0x02, 0x04} // 5e ^
,{0x40, 0x40, 0x40, 0x40, 0x40} // 5f _
,{0x00, 0x01, 0x02, 0x04, 0x00} // 60 `
,{0x20, 0x54, 0x54, 0x54, 0x78} // 61 a
,{0x7f, 0x48, 0x44, 0x44, 0x38} // 62 b
,{0x38, 0x44, 0x44, 0x44, 0x20} // 63 c
,{0x38, 0x44, 0x44, 0x48, 0x7f} // 64 d
,{0x38, 0x54, 0x54, 0x54, 0x18} // 65 e
,{0x08, 0x7e, 0x09, 0x01, 0x02} // 66 f
,{0x0c, 0x52, 0x52, 0x52, 0x3e} // 67 g
,{0x7f, 0x08, 0x04, 0x04, 0x78} // 68 h
,{0x00, 0x44, 0x7d, 0x40, 0x00} // 69 i
,{0x20, 0x40, 0x44, 0x3d, 0x00} // 6a j
,{0x7f, 0x10, 0x28, 0x44, 0x00} // 6b k
,{0x00, 0x41, 0x7f, 0x40, 0x00} // 6c l
,{0x7c, 0x04, 0x18, 0x04, 0x78} // 6d m
,{0x7c, 0x08, 0x04, 0x04, 0x78} // 6e n
,{0x38, 0x44, 0x44, 0x44, 0x38} // 6f o
,{0x7c, 0x14, 0x14, 0x14, 0x08} // 70 p
,{0x08, 0x14, 0x14, 0x18, 0x7c} // 71 q
,{0x7c, 0x08, 0x04, 0x04, 0x08} // 72 r
,{0x48, 0x54, 0x54, 0x54, 0x20} // 73 s
,{0x04, 0x3f, 0x44, 0x40, 0x20} // 74 t
,{0x3c, 0x40, 0x40, 0x20, 0x7c} // 75 u
,{0x1c, 0x20, 0x40, 0x20, 0x1c} // 76 v
,{0x3c, 0x40, 0x30, 0x40, 0x3c} // 77 w
,{0x44, 0x28, 0x10, 0x28, 0x44} // 78 x
,{0x0c, 0x50, 0x50, 0x50, 0x3c} // 79 y
,{0x44, 0x64, 0x54, 0x4c, 0x44} // 7a z
,{0x00, 0x08, 0x36, 0x41, 0x00} // 7b {
,{0x00, 0x00, 0x7f, 0x00, 0x00} // 7c |
,{0x00, 0x41, 0x36, 0x08, 0x00} // 7d }
,{0x10, 0x08, 0x08, 0x10, 0x08} // 7e ~
,{0x78, 0x46, 0x41, 0x46, 0x78} // 7f DEL
};

const char* ssid = "NETGEAR97"; // insert your SSID
const char* password = "rockyflower416"; // insert your password
const int httpPort = 1201; // Setting the communication port
String passingValue = "";
const char* host = "192.168.0.13";
String url = "/VarghaHokmran";
String varOne; // First variable that we are working with
String varTwo; // Second variable that we are working with

//There are two memory banks in the LCD, data/RAM and commands. This function
// sets the DC pin high or low depending, and then sends the data byte
void LCDWrite(byte data_or_command, byte data) {
digitalWrite(PIN_DC, data_or_command); //Tell the LCD that we are writing either to data or a command

//Send the data
digitalWrite(PIN_SCE, LOW);
shiftOut(PIN_SDIN, PIN_SCLK, MSBFIRST, data);
digitalWrite(PIN_SCE, HIGH);
}

void gotoXY(int x, int y) {
LCDWrite(0, 0x80 | x); // Column x - range: 0 to 84
LCDWrite(0, 0x40 | y); // Row y - range: 0 to 5
}

//This takes a large array of bits and sends them to the LCD
void LCDBitmap(char my_array[]){
for (int index = 0 ; index < (LCD_X * LCD_Y / 8) ; index++)
LCDWrite(LCD_DATA, my_array[index]);
}

//This function takes in a character, looks it up in the font table/array, and writes it to the screen
//Each character is 8 bits tall and 5 bits wide. We pad one blank column of pixels on each side of the character for readability.
void LCDCharacter(char character) {
LCDWrite(LCD_DATA, 0x00); //Blank vertical line padding

for (int index = 0 ; index < 5 ; index++)
LCDWrite(LCD_DATA, ASCII[character - 0x20][index]);
//0x20 is the ASCII character for Space (' '). The font table starts with this character

LCDWrite(LCD_DATA, 0x00); //Blank vertical line padding
}

//Given a string of characters, one by one is passed to the LCD
void LCDString(char *characters) {
while (*characters)
LCDCharacter(*characters++);
}

//Clears the LCD by writing zeros to the entire screen
void LCDClear(void) {
for (int index = 0 ; index < (LCD_X * LCD_Y / 8) ; index++)
LCDWrite(LCD_DATA, 0x00);
gotoXY(0, 0); //After we clear the display, return to the home position
}

//This sends the magical commands to the PCD8544
void LCDInit(void) {
//Configure control pins
pinMode(PIN_SCE, OUTPUT);
pinMode(PIN_RESET, OUTPUT);
pinMode(PIN_DC, OUTPUT);
pinMode(PIN_SDIN, OUTPUT);
pinMode(PIN_SCLK, OUTPUT);
//Reset the LCD to a known state
digitalWrite(PIN_RESET, LOW);
digitalWrite(PIN_RESET, HIGH);
LCDWrite(LCD_COMMAND, 0x21); //Tell LCD that extended commands follow
LCDWrite(LCD_COMMAND, 0xBF); //Set LCD Vop (Contrast): Try 0xB1(good @ 3.3V) or 0xBF if your display is too dark
LCDWrite(LCD_COMMAND, 0x04); //Set Temp coefficent
LCDWrite(LCD_COMMAND, 0x14); //LCD bias mode 1:48: Try 0x13 or 0x14
LCDWrite(LCD_COMMAND, 0x20); //We must send 0x20 before modifying the display control mode
LCDWrite(LCD_COMMAND, 0x0C); //Set display control, normal mode. 0x0D for inverse
}


/* -------------------------------------------- SETUP --------------------------------------------*/
void setup() {
LCDInit(); //Init the LCD
LCDClear();
gotoXY(0, 0);
LCDString(" ESP 8266");
gotoXY(0, 2);
LCDString(" By: Vargha");
gotoXY(0, 4);
LCDString("Thanks to:");
gotoXY(0, 5);
LCDString("Kendrick T.");
delay(3000);
LCDClear();
gotoXY(0, 2);
LCDString("Connecting ");
LCDString("to WiFi");

WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED) {
delay(500);
LCDString(".");
}

LCDClear();
gotoXY(0, 2);
LCDString(" WiFi ");
LCDString(" Connected! ");
delay(1000);
LCDClear();
}

/* -------------------------------------------- LOOP --------------------------------------------*/
void loop() {
gotoXY(0, 5);
LCDString("Please wait.");
// Use WiFiClient class to create TCP connections
WiFiClient client;
const int httpPort = 1201; // connection port. 80 for http
if (!client.connect(host, httpPort)) {
return;
}

// Here, you can put any variable that you would like to pass to PC
passingValue = "1234";

// This will send the request to the server
client.print(String("GET ") + url /*+ key*/ + passingValue + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"Connection: close\r\n\r\n");
delay(10);
/**************************************/
unsigned int i = 0; //timeout counter
int n = 1; // char counter
char json[500] ="{";
while (!client.find("myData: ")){}
while (i<600) {
if(client.available()) {
char c = client.read();
json[n]=c; // READ $ PRICE CHARACTERS INTO JSON ARRAY
if(c=='}') break;
n++;
i=0;
}
i++;
}

StaticJsonBuffer<500> jsonBuffer;
JsonObject& root = jsonBuffer.parseObject(json);

if (!root.success()) {
return;
}

LCDClear();
gotoXY(0, 0);
LCDString(" Please");
gotoXY(0, 2);
LCDString(" &");
gotoXY(0, 3);
varOne = root["otherText"].asString();

char charUSD[50];
varOne.toCharArray(charUSD, 50);

LCDString(charUSD);
/**************************************/
/**************************************/
i = 0; // timeout counter
n = 1; // char counter
while (i<600) {
if(client.available()) {
char c = client.read();
json[n]=c;
if(c=='}') break;
n++;
i=0;
}
i++;
}

StaticJsonBuffer<500> jsonBuffer2;
JsonObject& root2 = jsonBuffer2.parseObject(json);
if (!root.success()) {
return;
}
varTwo = root["myText"].asString();

char charName[50];
varTwo.toCharArray(charName, 50);

gotoXY(0, 1);
LCDString(charName);
/**************************************/

gotoXY(0, 5);
LCDString("Updated! ");

delay(1000);
gotoXY(0, 5);
LCDString(" ");

gotoXY(0, 5);
for (int x=0; x <= 11; x++){
LCDString(".");
delay(1000);
}

gotoXY(0, 5);
for (int x=0; x <= 11; x++){
LCDString(" ");
delay(1000);
}

varOne ="";
//varTwo ="";
}