POST JSON request using Apache HttpClient

To send a POST request with JSON payload using Apache HttpClient, you can follow the steps below:

• Create an instance of HttpClient using HttpClientBuilder.
• Create an instance of HttpPost with the target URL.
• Create a StringEntity with the JSON payload and set it as the entity of the HttpPost request.
• Set the content type header to application/json using setHeader.
• Execute the request using httpClient.execute(httpPost).
• Handle the response as needed.

Apache HttpClient Post Example code:

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

public class ApacheHttpClientPostJsonExample {
    public static void main(String[] args) {
        HttpClient httpClient = HttpClientBuilder.create().build();
        
        try {
            // Specify the URL endpoint for the POST request
            HttpPost httpPost = new HttpPost("http://example.com/api/resource");
            
            // Set the JSON payload
            String jsonPayload = "{\"name\":\"John\", \"age\":30}";
            StringEntity stringEntity = new StringEntity(jsonPayload, ContentType.APPLICATION_JSON);
            httpPost.setEntity(stringEntity);
            
            // Execute the request
            HttpResponse response = httpClient.execute(httpPost);
            
            // Get the response status code
            int statusCode = response.getStatusLine().getStatusCode();
            
            // Get the response body
            HttpEntity responseEntity = response.getEntity();
            String responseBody = EntityUtils.toString(responseEntity);
            
            // Close the response entity
            EntityUtils.consume(responseEntity);
            
            // Handle the response
            System.out.println("Response Code: " + statusCode);
            System.out.println("Response Body: " + responseBody);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // Close the HttpClient instance
            httpClient.getConnectionManager().shutdown();
        }
    }
}

In this example, we create an HttpPost instance with the target URL and set the JSON payload as a StringEntity. The StringEntity is created with the content type application/json using ContentType.APPLICATION_JSON.

After executing the request, we retrieve the response status code and body as before.

Remember to include the Apache HttpClient library in your project dependencies before running the code.

Thanks for Reading..