Java send POST request with JSON body

Oscar 171 Published: 09/03/2024

Java send POST request with JSON body

I'd be happy to help!

Java provides several ways to send a POST request with a JSON body. Here are a few examples:

Using the HttpClient library:

import java.io.BufferedReader;

import java.io.InputStreamReader;


import java.net.URI;


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.StringEntity;


import org.apache.http.impl.client.DefaultHttpClient;


import org.apache.http.params.BasicHttpParams;


public class Main {


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


// Create a new HTTP client


HttpClient httpClient = new DefaultHttpClient(new BasicHttpParams());


// Set up the POST request


HttpPost request = new HttpPost("http://example.com/api/endpoint");


request.addHeader("Content-Type", "application/json");


// Convert the JSON object to a string


String json = "{"key": "value"}";


StringEntity entity = new StringEntity(json, "UTF-8");


// Set the request body


request.setEntity(entity);


// Execute the POST request and get the response


HttpResponse response = httpClient.execute(request);


HttpEntity responseEntity = response.getEntity();


// Read the response content


BufferedReader reader = new BufferedReader(new InputStreamReader(responseEntity.getContent()));


String line;


StringBuilder result = new StringBuilder();


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


result.append(line);


}


// Print the response


System.out.println(result.toString());


}


}

Using the OkHttp library:

import okhttp3.FormBody;

import okhttp3.MediaType;


import okhttp3.OkHttpClient;


import okhttp3.Request;


import okhttp3.RequestBody;


public class Main {


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


// Create a new OkHttp client


OkHttpClient client = new OkHttpClient();


// Set up the POST request


RequestBody jsonBody = RequestBody.create(MediaType.get("application/json"), "{"key": "value"}");


FormBody formBody = new FormBody();


formBody.add("json", jsonBody);


// Execute the POST request and get the response


Request request = new Request.Builder()


.url("http://example.com/api/endpoint")


.post(formBody)


.build();


Response response = client.newCall(request).execute();


// Print the response


System.out.println(response.body().string());


}


}

Using the Apache CXF library:

import org.apache.cxf.jaxrs.client.WebClient;

public class Main {


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


// Create a new Web client


WebClient client = WebClient.create("http://example.com/api/endpoint");


// Set up the POST request with JSON body


client.accept(MediaType.APPLICATION_JSON_TYPE).post(JsonData(jsonBody));


// Execute the POST request and get the response


Response response = client.response();


// Print the response


System.out.println(response.body().toString());


}


public static JsonData jsonBody() {


// Create a JSON data object with the desired content


return new JsonData("{"key": "value"}");


}


}

These examples demonstrate how to send a POST request with a JSON body using the HttpClient, OkHttp, and Apache CXF libraries. The specific implementation may vary depending on your project requirements and the library you choose to use.

I hope this helps!

Java send POST request with body

I understand that you want me to explain how to send a POST request using Java and include a body in the request.

To achieve this, we can use the Apache HTTPClient library in Java. Here is an example of how to do it:

Firstly, add the following dependency to your Maven project (if you are using Maven):



org.apache.httpcomponents


httpclient


4.5.13

Or if you are not using Maven, add the HTTPClient JAR file to your classpath.

Here is a sample Java code that sends a POST request with a body:

import org.apache.http.HttpResponse;

import org.apache.http.client.methods.RequestBuilder;


import org.apache.http.entity.StringEntity;


import org.apache.http.impl.client.CloseableHttpClient;


import org.apache.http.impl.client.HttpClients;


public class Main {


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


// Create an HTTP client


CloseableHttpClient httpClient = HttpClients.createDefault();


// Build the POST request


RequestBuilder builder = RequestBuilder.post("http://example.com/api/endpoint");


StringEntity entity = new StringEntity("{"name":"John","age":30}", "UTF-8");


// Set the request content type to JSON


builder.setEntity(entity);


builder.addHeader("Content-Type", "application/json; charset=utf-8");


// Send the POST request and get the response


HttpResponse response = builder.build().execute(httpClient);


// Read the response


int status = response.getStatusLine().getStatusCode();


if (status == 200) {


System.out.println("POST request sent successfully!");


} else {


System.out.println("Error: " + status);


}


}


}

This code sends a POST request to http://example.com/api/endpoint with a JSON body that contains two key-value pairs: "name" with value "John", and "age" with value 30. The response is then printed out.

You can adjust the URL, JSON body, and headers according to your specific requirements.

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