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How to send HTTP request GET/POST in Java

Java http requests

In this article, we will show you a few examples to make HTTP GET/POST requests via the following APIs

  • Apache HttpClient 4.5.10
  • OkHttp 4.2.2
  • Java 11 HttpClient
  • Java 1.1 HttpURLConnection (Not recommend)

1. Apache HttpClient

In the old days, this Apache HttpClient is the de facto standard to send an HTTP GET/POST request in Java.

pom.xml

	<dependency>
		<groupId>org.apache.httpcomponents</groupId>
		<artifactId>httpclient</artifactId>
		<version>4.5.10</version>
	</dependency>
HttpClientExample.java

package com.mkyong.http;

import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpHeaders;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class HttpClientExample {

    // one instance, reuse
    private final CloseableHttpClient httpClient = HttpClients.createDefault();

    public static void main(String[] args) throws Exception {

        HttpClientExample obj = new HttpClientExample();

        try {
            System.out.println("Testing 1 - Send Http GET request");
            obj.sendGet();

            System.out.println("Testing 2 - Send Http POST request");
            obj.sendPost();
        } finally {
            obj.close();
        }
    }

    private void close() throws IOException {
        httpClient.close();
    }

    private void sendGet() throws Exception {

        HttpGet request = new HttpGet("https://www.google.com/search?q=mkyong");

        // add request headers
        request.addHeader("custom-key", "mkyong");
        request.addHeader(HttpHeaders.USER_AGENT, "Googlebot");

        try (CloseableHttpResponse response = httpClient.execute(request)) {

            // Get HttpResponse Status
            System.out.println(response.getStatusLine().toString());

            HttpEntity entity = response.getEntity();
            Header headers = entity.getContentType();
            System.out.println(headers);

            if (entity != null) {
                // return it as a String
                String result = EntityUtils.toString(entity);
                System.out.println(result);
            }

        }

    }

    private void sendPost() throws Exception {

        HttpPost post = new HttpPost("https://httpbin.org/post");

        // add request parameter, form parameters
        List<NameValuePair> urlParameters = new ArrayList<>();
        urlParameters.add(new BasicNameValuePair("username", "abc"));
        urlParameters.add(new BasicNameValuePair("password", "123"));
        urlParameters.add(new BasicNameValuePair("custom", "secret"));

        post.setEntity(new UrlEncodedFormEntity(urlParameters));

        try (CloseableHttpClient httpClient = HttpClients.createDefault();
             CloseableHttpResponse response = httpClient.execute(post)) {

            System.out.println(EntityUtils.toString(response.getEntity()));
        }

    }

}
Note
Read more Apache HttpClient examples

2. OkHttp

This OkHttp is very popular on Android, and widely use in many web projects, the rising star.

pom.xml

	<dependency>
		<groupId>com.squareup.okhttp3</groupId>
		<artifactId>okhttp</artifactId>
		<version>4.2.2</version>
	</dependency>
OkHttpExample.java

package com.mkyong.http;

import okhttp3.*;

import java.io.IOException;

public class OkHttpExample {

    // one instance, reuse
    private final OkHttpClient httpClient = new OkHttpClient();

    public static void main(String[] args) throws Exception {

        OkHttpExample obj = new OkHttpExample();

        System.out.println("Testing 1 - Send Http GET request");
        obj.sendGet();

        System.out.println("Testing 2 - Send Http POST request");
        obj.sendPost();

    }

    private void sendGet() throws Exception {

        Request request = new Request.Builder()
                .url("https://www.google.com/search?q=mkyong")
                .addHeader("custom-key", "mkyong")  // add request headers
                .addHeader("User-Agent", "OkHttp Bot")
                .build();

        try (Response response = httpClient.newCall(request).execute()) {

            if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

            // Get response body
            System.out.println(response.body().string());
        }

    }

    private void sendPost() throws Exception {

        // form parameters
        RequestBody formBody = new FormBody.Builder()
                .add("username", "abc")
                .add("password", "123")
                .add("custom", "secret")
                .build();

        Request request = new Request.Builder()
                .url("https://httpbin.org/post")
                .addHeader("User-Agent", "OkHttp Bot")
                .post(formBody)
                .build();

        try (Response response = httpClient.newCall(request).execute()) {

            if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

            // Get response body
            System.out.println(response.body().string());
        }

    }

}
Note
Read more OkHttp examples

3. Java 11 HttpClient

In Java 11, a new HttpClient is introduced in package java.net.http.*

The sendAsync() will return a CompletableFuture, it makes concurrent requests much easier and flexible, no more external libraries to send an HTTP request!

Java11HttpClientExample.java

package com.mkyong.http;

import java.net.URI;
import java.net.URLEncoder;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;

public class Java11HttpClientExample {

    // one instance, reuse
    private final HttpClient httpClient = HttpClient.newBuilder()
            .version(HttpClient.Version.HTTP_2)
            .build();

    public static void main(String[] args) throws Exception {

        Java11HttpClientExample obj = new Java11HttpClientExample();

        System.out.println("Testing 1 - Send Http GET request");
        obj.sendGet();

        System.out.println("Testing 2 - Send Http POST request");
        obj.sendPost();

    }

    private void sendGet() throws Exception {

        HttpRequest request = HttpRequest.newBuilder()
                .GET()
                .uri(URI.create("https://httpbin.org/get"))
                .setHeader("User-Agent", "Java 11 HttpClient Bot")
                .build();

        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

        // print status code
        System.out.println(response.statusCode());

        // print response body
        System.out.println(response.body());

    }

    private void sendPost() throws Exception {

        // form parameters
        Map<Object, Object> data = new HashMap<>();
        data.put("username", "abc");
        data.put("password", "123");
        data.put("custom", "secret");
        data.put("ts", System.currentTimeMillis());

        HttpRequest request = HttpRequest.newBuilder()
                .POST(buildFormDataFromMap(data))
                .uri(URI.create("https://httpbin.org/post"))
                .setHeader("User-Agent", "Java 11 HttpClient Bot") // add request header
                .header("Content-Type", "application/x-www-form-urlencoded")
                .build();

        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

        // print status code
        System.out.println(response.statusCode());

        // print response body
        System.out.println(response.body());

    }

    private static HttpRequest.BodyPublisher buildFormDataFromMap(Map<Object, Object> data) {
        var builder = new StringBuilder();
        for (Map.Entry<Object, Object> entry : data.entrySet()) {
            if (builder.length() > 0) {
                builder.append("&");
            }
            builder.append(URLEncoder.encode(entry.getKey().toString(), StandardCharsets.UTF_8));
            builder.append("=");
            builder.append(URLEncoder.encode(entry.getValue().toString(), StandardCharsets.UTF_8));
        }
        System.out.println(builder.toString());
        return HttpRequest.BodyPublishers.ofString(builder.toString());
    }

}
Note
Read more Java 11 HttpClient examples

4. HttpURLConnection

This HttpURLConnection class is available since Java 1.1, uses this if you dare 🙂 Generally, it’s NOT recommend to use this class, because the codebase is very old and outdated, it may not supports the new HTTP/2 standard, in fact, it’s really difficult to configure and use this class.

The below example is just for self reference, NOT recommend to use this class!

HttpURLConnectionExample.java

package com.mkyong.http;

import javax.net.ssl.HttpsURLConnection;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpURLConnectionExample {

    public static void main(String[] args) throws Exception {

        HttpURLConnectionExample obj = new HttpURLConnectionExample();

        System.out.println("Testing 1 - Send Http GET request");
        obj.sendGet();

        System.out.println("Testing 2 - Send Http POST request");
        obj.sendPost();

    }

    private void sendGet() throws Exception {

        String url = "https://www.google.com/search?q=mkyong";

        HttpURLConnection httpClient =
                (HttpURLConnection) new URL(url).openConnection();

        // optional default is GET
        httpClient.setRequestMethod("GET");

        //add request header
        httpClient.setRequestProperty("User-Agent", "Mozilla/5.0");

        int responseCode = httpClient.getResponseCode();
        System.out.println("\nSending 'GET' request to URL : " + url);
        System.out.println("Response Code : " + responseCode);

        try (BufferedReader in = new BufferedReader(
                new InputStreamReader(httpClient.getInputStream()))) {

            StringBuilder response = new StringBuilder();
            String line;

            while ((line = in.readLine()) != null) {
                response.append(line);
            }

            //print result
            System.out.println(response.toString());

        }

    }

    private void sendPost() throws Exception {

		// url is missing?
        //String url = "https://selfsolve.apple.com/wcResults.do";
        String url = "https://httpbin.org/post";

        HttpsURLConnection httpClient = (HttpsURLConnection) new URL(url).openConnection();

        //add reuqest header
        httpClient.setRequestMethod("POST");
        httpClient.setRequestProperty("User-Agent", "Mozilla/5.0");
        httpClient.setRequestProperty("Accept-Language", "en-US,en;q=0.5");

        String urlParameters = "sn=C02G8416DRJM&cn=&locale=&caller=&num=12345";

        // Send post request
        httpClient.setDoOutput(true);
        try (DataOutputStream wr = new DataOutputStream(httpClient.getOutputStream())) {
            wr.writeBytes(urlParameters);
            wr.flush();
        }

        int responseCode = httpClient.getResponseCode();
        System.out.println("\nSending 'POST' request to URL : " + url);
        System.out.println("Post parameters : " + urlParameters);
        System.out.println("Response Code : " + responseCode);

        try (BufferedReader in = new BufferedReader(
                new InputStreamReader(httpClient.getInputStream()))) {

            String line;
            StringBuilder response = new StringBuilder();

            while ((line = in.readLine()) != null) {
                response.append(line);
            }

            //print result
            System.out.println(response.toString());

        }

    }

}

References

113 comments on “How to send HTTP request GET/POST in Java”

  4. I was wondering if I would need to send post requests to fill in a login form? I am not sure how I would do this using HttpClient and HTML 2.

    Reply

  5. Thanks mkyong for this tutorial, very informative and helpful.
    I tried with Java versions 11, 12, 13 in Intellij, but java.net.http.HttpClient is not detected. Automatically sun.net.http.HttpClient is getting imported.
    Cant we send request to a URL using sun.net.http.HttpClinet ?
    My requirement is to read the data placed in a CSV file using URL.

    Reply

  11. Hi,
    I am trying to display the output from a simple while loop to angular front-end. Could you please help me in this regard?

    Reply

  14. Hi
    Can you please explain more about “sn”, “cn”, “locale”, “caller”, “num” ??
    where can i get information of different parameters.
    Thank you in advance

    Reply

  24. Hi, i am getting this exception when i try to open connection

    Info: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

    I can not understand why open this connection requires a certificate. This is related with the agent used (mozilla)?

    Reply

  30. Hi,
    I have a java standalone server which listen the request and then I open a socket connection. My requirement is, how can I know weather java client is using http or https protocol in my server programe.

    Reply

  32. Hi ,
    After implementation i got below security related bug.

    The call to HttpHost() (in my class on line 113 )uses an unencrypted protocol instead of an encrypted protocol to communicate with the server.

    code:
    private HttpHost getHttpProxy(String proxyHost,int proxyPort) {
    return new HttpHost(proxyHost, proxyPort);
    }

    so how can i encrypt it?

    Reply

  33. Thank for Sharing this post with us. Very Helpfull and usefull Information. Hope you keep it up in future also by providing informative post.This Post is very much handy.Best of Luck & Cheers.
    Thank You

    Reply

  34. Thank You for giving us idea about how to send HTTP request GET/POST in Java.
    Thank You Very Much For Sharing Your Knowledge with US.Now a Day No Body Do what you did.We are really blessed with this types of informatic Posting. Hope you continue this in Future.Keep us updated with this this types of blogs.Best of Luck & Cheers.
    Thanks David

    Reply

    1. replace the next lines

      List urlParameters = new ArrayList();
      urlParameters.add(new BasicNameValuePair(“sn”, “C02G8416DRJM”));
      urlParameters.add(new BasicNameValuePair(“cn”, “”));
      urlParameters.add(new BasicNameValuePair(“locale”, “”));
      urlParameters.add(new BasicNameValuePair(“caller”, “”));
      urlParameters.add(new BasicNameValuePair(“num”, “12345”));

      post.setEntity(new UrlEncodedFormEntity(urlParameters));

      with

      post.setEntity(new StringEntity(“{“sn”:”C02G8416DRJM”}”,ContentType.create(“application/json”)));

      Reply

  37. I just copied the post method u’ve created and wanted to use it somewhere the same way as you did. It is just like your class but without the get() thing

    when I run it on one site of mine i get:

    java.lang.ClassCastException: sun.net.www.protocol.http.HttpURLConnection cannot be cast to javax.net.ssl.HttpsURLConnection
    at tests.web.POSTRequestTest.sendPost(POSTRequestTest.java:32)
    at tests.web.POSTRequestTest.main(POSTRequestTest.java:18)

    Reply

  39. I dont understand the method for the http connection example could someone please explain it using an example . you know one with an actual url and parameters and api call

    Reply

  40. Hi,
    Thank you for these useful examples!

    When I used the Java Post example, I’ve encountered some issues when sending content than contains non English characters.

    Investigating it showed that the cause is the usage of DataOutputStream.writeBytes(). From this class documentation: “Each character in the string is written out, in sequence, by discarding its high eight bits.”

    The solution is to use:
    Writer out = new BufferedWriter(new OutputStreamWriter(con.getOutputStream()));
    out.write(urlParameters);

    Reply

  41. Hi all
    The example with HttpURLConnection does not work, I have been looking for a solution but I have not found my error is this:
    java.net.ConnectException: Connection refused: connect…
    The server is active, port 8000 is active, it is in a local environment

    Reply

  42. this perfectly working. but when i use java Swing i can’t pass the parameters to urlParameters from jTextField.

    CODE:
    String urlParameters = “NAME=”+jTextField_name.getText()+”&address=”+jTextField_add.getText();

    OUTPUT:
    Post parameters :NAME=&address=

    also i assign “jTextField_name.getText()” to variable but output was same.

    so can you solved this problem

    Reply

    1. This error is not a problem with the code sample given above but it means that the server that you are attempting to connect to is secured with a certificate. You will need to add that severs certificate to your local keystore.

      Reply

  46. HI mkyong why i have this error ?
    \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
    Exception in thread “main” java.lang.RuntimeException: Uncompilable source code – cannot find symbol
    symbol: class HttpURLConnectionExample
    location: class lab1.Lab1
    at lab1.Lab1.main(Lab1.java:27)
    Java Result: 1
    BUILD SUCCESSFUL (total time: 2 seconds)
    \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

    Reply

  47. Can you describe not how to send but how to recieve POST or GET request? I would like to recieve POST for example, but without using servlets. I would rather use JQuery and send POST to .jar file. Can it be done?

    Reply

  53. i am getting connection time out error………and javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException

    Reply

  54. When I connect to Bing or Yahoo I dont need to provide User-Agent but when I connect to Yahoo, I do need to provide User-Agent, what is the reason?

    Reply

  58. If I have given the Url of a jsp page and set parameters using setEntity, how can i get those parameters in the jsp page? Please help.

    Reply

  59. HttpClient jar does not provide HttpResponse class.
    i am using httpclient-4.4.1.jar
    how can i get httpresponse?

    Reply

  62. Respected sir,

    sir i am working in the BSNL in INDIA as a ADSL broadband engineer.
    i configure lots of modem in a day using web based configuration of the adsl modem like..tplink , linksys cisco , netgear etc…..
    sir i used only 4 variable parameter like PPPOE USERNAME…PPPOE PASSWORD….SSID…WIFIPASSWORD…..

    Sir i want to build a desktop application using java which automatic configure my adsl modem .
    is it possible to do such using get and post method like login to gmail ?
    my e mail is –[email protected]

    Reply

  63. Thanks for nice tut. But i have a problem when using http request to get response from website which using javascript to loading data. Any one tell me how to get all data contents from website using JS to load data. I have used Jsoup but i can’t get data. Many thanks.

    Reply

  74. Sir i need to test webservices using java…I have framework build using selenium…please suggest how should i proceed….I am new to java…i see lot of articles which help develop webservice…publish it..etc

    my simple problem statement is that we have webservices which has end point url…request…wsdl…and we want to capture the response (which can be xml or jason) and want to read and validate it…please suggest best possible way

    Reply

    1. Sir,I am trying to do exactly the same thing. Automate the testing of websevices using Java that is. Can you advise me on how to proceed. I hope you have completed your project.

      Reply

  77. Hi,
    I have tried the above example “Send an HTTP GET request to Google.com to get the search result”
    but I am getting the exception : “Exception in thread “main” java.net.ConnectException: Connection timed out: connect” so what could be the reason ?? Is there any set up is required or what ??
    Please let me know how can I use this for TestNG and please give me a example.

    Reply

  80. First, you are The Man! Every time I google, your answers come up at the top! Thanks for sharing your knowledge.

    I have a question about UrlConnection.connect(). I noticed you didn’t invoke that method. Does requesting the response code trigger an automatic connection?

    Reply

  83. hi there,

    it’s strange – on get request i’ll get the whole HTML Content.

    But when i do a post request, there will be nothing although the response code is 302 (found), the redirect url is the correct one.

    any ideas on this? thanks

    Reply

  84. hi

    i want to connect a web service its adreses are

    Web Servisi Adresi :
    real url : https://medeczane.sgk.gov.tr/eczanews/services/SaglikTesisiReceteIslemleri
    Test url : http://saglikt.sgk.gov.tr/eczanews/services/SaglikTesisiReceteIslemleri
    Web Servisi WSDL Adresi :
    real WSDL : https://medeczane.sgk.gov.tr/eczanews/services/SaglikTesisiReceteIslemleri/wsdl/SaglikTesisiReceteIslemleri.wsdl
    Test WSDL: http://saglikt.sgk.gov.tr/eczanews/services/SaglikTesisiReceteIslemleri/wsdl/SaglikTesisiReceteIslemleri.wsdl

    username is 99999999990 and passwork is 99999999990. i must send it with http header to gss server. i must send this request in every SOAP request. can you help me please…

    Reply

  85. Hi, I have a problem runing the first example, this is the error:

    java.net.ConnectException: Connection timed out: connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
    at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
    at java.net.Socket.connect(Socket.java:519)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:550)
    at com.sun.net.ssl.internal.ssl.BaseSSLSocketImpl.connect(BaseSSLSocketImpl.java:141)
    at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:394)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:529)
    at sun.net.www.protocol.https.HttpsClient.(HttpsClient.java:271)
    at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:328)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:793)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158)
    at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:896)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:230)

    Can you help me please?

    PD, Sorry, but I don’t write in english good…

    Reply

  86. Hi,

    I am trying to write similar code to check a server status.
    However, i wish to retry up to 5 times in case of failure to connect.
    Is there an option for that ?

    package home.always.learning.java;

    import java.net.ConnectException;
    import java.net.HttpURLConnection;
    import java.net.URL;

    /**
    *
    *
    */
    public class DialServer {

    private static final String url = “http://localhost”;
    private static final String requestMethod = “GET”;

    // HTTP GET request

    public static void main(String[] args) {
    checkServer();
    }

    private static void checkServer() {

    try {
    sendGet();
    } catch (ConnectException e) {
    System.out.println(“Connect Exception..Try Again Till Max Attempts…”);
    e.printStackTrace();
    } catch (Exception e){
    e.printStackTrace();
    }
    }

    private static void sendGet() throws Exception {

    URL obj = new URL(url);
    HttpURLConnection con = (HttpURLConnection) obj.openConnection();
    // optional default is GET
    con.setRequestMethod(requestMethod);
    System.out.println(con.getInputStream());
    int responseCode = con.getResponseCode();
    System.out.println(“Response Code : ” + responseCode);
    }
    }

    Reply

      1. Alex,
        Thanks for your response. I did put the code to run in a loop and succeeded. However, if the server i am pinging is offline; i get a connect exception. Hence, i have to initiate my code to check again from the catch block. Per standards, is that a good thing to do, i.e. initiate a possible processing logic from catch block ???
        Else, i did get the code to work.

        public static void checkServer() {

        for (int i = 0; i <= maxAttempts; i++) {
        try {
        int responseCode = sendGet();
        if(responseCode==200)
        {
        System.out.println("Break Loop and Return");
        break;
        }
        } catch (ConnectException e) {
        if(i==maxAttempts)
        {
        System.out.println("Max Attempts Have Reached for Server Response…ALERT Now");
        }
        else
        {
        System.out.println("Connect Exception..Try Again Till Max Attempts…");
        try {
        Thread.currentThread().sleep(retryPeriod);
        } catch (InterruptedException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
        }
        }
        } catch (Exception e) {
        System.out.println("Generic Exception Connecting To Server…");
        e.printStackTrace();
        }
        }
        }

        Reply

        1. “is that a good thing to do, i.e. initiate a possible processing logic from catch block ???”

          I haven’t studied your code thouroughly, but I think that catching exceptions and trying a gin is one of the whole points of try-catch blocks. To have exceptions and still keep the program run without terminating with an exception thrown from the main() method.

          Reply

          1. I have asked for a review on the same point but did not receive much inputs.
            However, i have observed some business scenarios where a business action will be performed in case an exception occurred. Considering this, i wrote the code involving catch.
            Another reason was that if the server was not online; Java was throwing a connect exception and not giving some “code” to check the status. Else, an if-else construct would have helped me.

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