I need help with arduino shield ethernet

Good evenings.
I began it does little with a project with shield ethernet and I have a doubt with the programming still not greatly but I have something, the problem is the following one with a sensor dht 21 I want that the value that delivers me so much in temperature and dampness registers in a file txt and then it me it stamps on a web page created that this inside the same card alone SD successful eh to guard the value in a file but not as stamping it on the page, I leave the code of what I take for if someone can help me For his attention thank you very much.

sorry my english not is good

#include <SD.h>
#include <DHT.h>

const int chipSelect = 4;
#define DHTTYPE DHT21                     
#define DHTPIN 2                             
 
DHT dht(DHTPIN, DHTTYPE);
 
void setup()
{

  Serial.begin(9600);
   while (!Serial) {
    ; 
  }


  Serial.print("Initializing SD card...");
  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(10, OUTPUT);
  
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
    // don't do anything more:
    return;
  }
  Serial.println("card initialized.");
}

void loop()
{
 String dataString = "";
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  
  
    int sensor = t;
      int sensor1 = h;
    dataString += String(sensor );
     dataString += String(" C");
      dataString += String( "  " );
            dataString += String( "  " );
        dataString += String(sensor1  );
         dataString += String(" %");
  
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  
  if (t >21 || h > 46){
  File dataFile = SD.open("temperat.txt", FILE_WRITE);

  // if the file is available, write to it:
  if (dataFile) {
    dataFile.println(dataString);
    dataFile.close();
    // print to the serial port too:
    Serial.println(dataString);
  }  
  // if the file isn't open, pop up an error:
  else {
    Serial.println("error opening temperat.txt");
  } 
}
}
 String dataString = "";

Don't go there.

Data written to a file on an SD card is already buffered. Storing all the data in a resource wasting String does not help performance.

I see nothing in that code that does anything with any web page. It does not generate a page. It does not request a page.

sorry my english not is good

Maybe you should try Google Translate.

google is worse .. but I need to solve the project at this time.

I agree with PaulS. I see nothing that initializes the w5100, nor anything about a webpage in your code. I see only the SD card initialized, and you are lucky it starts ok with the w5100 SPI active.

Hi
I need to link this code with the above or any other ideas how to do it help me a lot

#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>
#include <DHT.h>
// size of buffer used to capture HTTP requests
#define REQ_BUF_SZ   20
#define DHTTYPE DHT21                    
#define DHTPIN 2                               
 
DHT dht(DHTPIN, DHTTYPE);
// MAC address from Ethernet shield sticker under board
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(192, 168, 0, 3); // IP address, may need to change depending on network
EthernetServer server(80);  // create a server at port 80
File webFile;
char HTTP_req[REQ_BUF_SZ] = {0}; // buffered HTTP request stored as null terminated string
char req_index = 0;              // index into HTTP_req buffer

void setup()
{
    // disable Ethernet chip
    pinMode(10, OUTPUT);
    digitalWrite(10, HIGH);
    
    Serial.begin(9600);       // for debugging
    
    // initialize SD card
    Serial.println("Initializing SD card...");
    if (!SD.begin(4)) {
        Serial.println("ERROR - SD card initialization failed!");
        return;    // init failed
    }
    Serial.println("SUCCESS - SD card initialized.");
    // check for index.htm file
    if (!SD.exists("index.htm")) {
        Serial.println("ERROR - Can't find index.htm file!");
        return;  // can't find index file
    }
    Serial.println("SUCCESS - Found index.htm file.");
    
    Ethernet.begin(mac, ip);  // initialize Ethernet device
    server.begin();           // start to listen for clients
}

void loop()
{
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  
  if (isnan(t) || isnan(h)) 
   Serial.println("Failed to read from DHT");
   else {
    EthernetClient client = server.available();  // try to get client

    if (client) {  // got client?
        boolean currentLineIsBlank = true;
        while (client.connected()) {
            if (client.available()) {   // client data available to read
                char c = client.read(); // read 1 byte (character) from client
                // buffer first part of HTTP request in HTTP_req array (string)
                // leave last element in array as 0 to null terminate string (REQ_BUF_SZ - 1)
                if (req_index < (REQ_BUF_SZ - 1)) {
                    HTTP_req[req_index] = c;          // save HTTP request character
                    req_index++;
                }
                // print HTTP request character to serial monitor
                Serial.print(c);
                // last line of client request is blank and ends with \n
                // respond to client only after last line received
                if (c == '\n' && currentLineIsBlank) {
                    // open requested web page file
                    if (StrContains(HTTP_req, "GET / ") || StrContains(HTTP_req, "GET /index.htm")) {
                        client.println("HTTP/1.1 200 OK");
                        client.println("Content-Type: text/html");
                        client.println("Connnection: close");
                        client.println("<!DOCTYPE HTML>");
                                   client.println("<html>");
                                    client.println("");                                             
                        webFile = SD.open("index.htm"); 
                        client.println("</html>"); 
                   client.print(h +10 );  
                   client.print(t);       
                    }
           
                     else if (StrContains(HTTP_req, "GET /historico.htm")) { 
                     client.println("HTTP/1.1 200 OK");
                          client.println("Content-Type: text/html");
                        client.println("Connnection: close");
                        client.println();
                              
                        webFile = SD.open("historico.htm"); 
                      }
                      
                    else if (StrContains(HTTP_req, "GET /logo.png")) {
                        webFile = SD.open("logo.png");
                        if (webFile) {
                            client.println("HTTP/1.1 200 OK");
                            client.println();
                        }
                    }
                    if (webFile) {
                        while(webFile.available()) {
                            client.write(webFile.read()); // send web page to client
                        }
                        webFile.close();
                    }
                    // reset buffer index and all buffer elements to 0
                    req_index = 0;
                    StrClear(HTTP_req, REQ_BUF_SZ);
                    break;
                }
                // every line of text received from the client ends with \r\n
                if (c == '\n') {
                    // last character on line of received text
                    // starting new line with next character read
                    currentLineIsBlank = true;
                } 
                else if (c != '\r') {
                    // a text character was received from client
                    currentLineIsBlank = false;
                }
            } // end if (client.available())
        } // end while (client.connected())
    }
        delay(1);      // give the web browser time to receive the data
        client.stop(); // close the connection
    } // end if (client)
}

// sets every element of str to 0 (clears array)
void StrClear(char *str, char length)
{
    for (int i = 0; i < length; i++) {
        str[i] = 0;
    }
}

// searches for the string sfind in the string str
// returns 1 if string found
// returns 0 if string not found
char StrContains(char *str, char *sfind)
{
    char found = 0;
    char index = 0;
    char len;

    len = strlen(str);
    
    if (strlen(sfind) > len) {
        return 0;
    }
    while (index < len) {
        if (str[index] == sfind[found]) {
            found++;
            if (strlen(sfind) == found) {
                return 1;
            }
        }
        else {
            found = 0;
        }
        index++;
    }

    return 0;
}

I need to link this code with the above

This crap, you mean. You don't seem to have learned the benefits of properly indented code from a readability/comprehensibility/maintainability point of view. Tools + Auto Format is there for a reason.

Regardless, you have our permission to merge the two codes. Without knowing what your requirements are for the resulting program, we can't help you do it.