How to get OAuth 2.0 Bearer Access Token using Java HTTP POST Request

How to get OAuth 2.0 Bearer Access Token

Hello everyone, Welcome to techxon. In this Java tutorial we discuss how to get OAuth 2.0 Bearer Access Token using Java HTTP POST request. Simply you can use this java class for get OAuth 2.0 bearer access token. This POST request Content-Type is "application/x-www-form-urlencoded". First you need some important parameters for this make this request.

grant_type
client_id
client_secret

These parameters are mandatory for this application/x-www-form-urlencoded POST request. Let's discuss step by step.

Encode parameters

//Encode parameters

String grant_type = URLEncoder.encode("your_grant_type", "UTF-8");

String client_id = URLEncoder.encode("your_id", "UTF-8");

String client_secret = URLEncoder.encode("your_secret", "UTF-8");

Create request body data URL

//Request body data

String postDataParams = "grant_type=" + grant_type + "&client_id=" + client_id + "&client_secret=" + client_secret;

Open connection

URL url = new URL("your_url");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setRequestProperty("Content-Length", String.valueOf(postDataParams.length()));

Write data

//Write data

OutputStream outStream = connection.getOutputStream();

outStream.write(postDataParams.getBytes());

Read response

//Read response

StringBuilder strBuilder = new StringBuilder();

BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));

String line;

while ((line = br.readLine()) != null) {

strBuilder.append(line);

}

Close BufferedReader and OutputStream

//close BufferedReader and OutputStream

br.close();

outStream.close();

Print response

//print response

System.out.println("Response : " + strBuilder.toString());

Response converted to JSON object

//response converted to JSON object

JSONObject jOb = new JSONObject(strBuilder.toString());

//print JSON object

System.out.println("JSON Object : " + jOb);

Print Bearer Access Token

//get access token

String access_token = jOb.getString("access_token");

//print access token

System.out.println("Bearer Token : " + access_token);

Complete Java Class

package yourpackagename;

//imports

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLEncoder;

import org.json.JSONException;

import org.json.JSONObject;

/**

* @author Gayan Ruchiranga

public class GetBearerAccessToken {

public static void main(String[] args) {

try {

//Encode parameters

String grant_type = URLEncoder.encode("your_grant_type", "UTF-8");

String client_id = URLEncoder.encode("your_id", "UTF-8");

String client_secret = URLEncoder.encode("your_secret", "UTF-8");

//Request body data

String postDataParams = "grant_type=" + grant_type + "&client_id=" + client_id + "&client_secret=" + client_secret;

URL url = new URL("your_url");

HttpURLConnection connection = (HttpURLConnection) url.openConnection();

connection.setDoOutput(true);

connection.setRequestMethod("POST");

connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

connection.setRequestProperty("Content-Length", String.valueOf(postDataParams.length()));