Java: How to make API call with data?

Question

I want to make API call similar to below curl command:

curl -X POST -H "Content-Type: application/json" -H "Authorization: Bearer 
1djCb/mXV+KtryMxr6i1bXw" 
-d '{"operands":[]}' 
https://ads.line.me/api/v1.0/authority_delegations/get

What I am trying

public void send_deligation_request(String details[]) throws Exception{
    System.out.println(Arrays.toString(details));

    URL line_api_url = new URL("https://ads.line.me/api/v1.0/authority_delegations/get");
    String payload = "{operands:[]}";



    HttpURLConnection linec = (HttpURLConnection)line_api_url.openConnection();
    linec.setDoInput(true);
    linec.setDoOutput(true);
    linec.setRequestMethod("POST");
    linec.setRequestProperty("Content-Type", "application/json");
    linec.setRequestProperty("Authorization", "Bearer "+access_token);

    OutputStreamWriter writer = new OutputStreamWriter(linec.getOutputStream(), "UTF-8");
    writer.write(payload);


    BufferedReader in = new BufferedReader(
                            new InputStreamReader(
                                    linec.getInputStream()));
    String inputLine;

    while ((inputLine = in.readLine()) != null) 
        System.out.println(inputLine);
    in.close();
}

But I am getting below error:

[naofumi.haida@torchlight.co.jp, 5514]

java.io.IOException: Server returned HTTP response code: 400 for URL: https://ads.line.me/api/v1.0/authority_delegations/get
  at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1840)
  at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1441)
  at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
  at AuthorityDelegation.send_deligation_request(AuthorityDelegation.java:66)
  at AuthorityDelegation.read_csv(AuthorityDelegation.java:36)
  at AuthorityDelegation.main(AuthorityDelegation.java:20)

Could somebody please help me?

Answer 1

Scala Code to get data from Splunk API and compress the certification/SSL error:

import java.nio.charset.StandardCharsets
import java.security.cert.X509Certificate
import java.util.{ArrayList, List}

import javax.net.ssl.SSLContext
import org.apache.commons.codec.binary.Base64
import org.apache.http.NameValuePair
import org.apache.http.client.HttpClient
import org.apache.http.client.methods.HttpPost
import org.apache.http.conn.ssl.{NoopHostnameVerifier, TrustSelfSignedStrategy}
import org.apache.http.impl.client.HttpClients
import org.apache.http.message.BasicNameValuePair
import org.apache.http.ssl.SSLContextBuilder

class test {


  val sslContext: SSLContext = new SSLContextBuilder()
    .loadTrustMaterial(null, new TrustSelfSignedStrategy() {
      override def isTrusted(chain: Array[X509Certificate],
                             authType: String): Boolean = true
    })
    .build()

  val httpclient: HttpClient = HttpClients
    .custom()
    .setSSLContext(sslContext)
    .setSSLHostnameVerifier(new NoopHostnameVerifier())
    .build()
  val httpPost: HttpPost = new HttpPost(
    "https://splunk-api:8089/servicesNS/nobody/search/search/jobs/export")

  val params: List[NameValuePair] = new ArrayList[NameValuePair]()
  val searchString: String =
    "search index=prod_applogs OR index=prod_applogs source=\"*subscriber-daemon-*\" Data  Mutation | lookup data_clients.csv client OUTPUTNEW pow AS pow | stats count as numEvents, min(_time) as minTime by pow, Name | eval cost=round(exact(numEvents*0.000003),2)|eval date=strftime(minTime, \"%Y-%m-%d\")|fields *"
  params.add(new BasicNameValuePair("search", searchString))
  params.add(new BasicNameValuePair("output_mode", "csv"))
  params.add(new BasicNameValuePair("earliest_time", "1h"))
  params.add(new BasicNameValuePair("latest_time", "now"))


  val username: String = "userName"
  val password: String = "pwd"
  val auth: String = username + ":" + password

  val encodedAuth: Array[Byte] =
    Base64.encodeBase64(auth.getBytes(StandardCharsets.ISO_8859_1))
  val authHeaderVal: String = "Basic " + new String(encodedAuth)

}

Answer 2

Thanks everyone for your help. I used below code to make it work.

public JSONObject send_post() {
    HttpClient httpClient = HttpClientBuilder.create().build();
    JSONObject jsonObject = null;

    try {

        HttpPost request = new HttpPost(this.URL + this.object_type + this.request_type);
        StringEntity params = null;
        if (this.request_type.equals("/get")) {
            params = new StringEntity("{\"accountId\":\"5514\"}");
        } else if (this.request_type.equals("/set")) {
            // params = new
            // StringEntity("{\"accountId\":\"5514\",\"operands\":[{\"id\":40151,\"name\":\"ddddd\"}]}");
            String output = String.format("{\"accountId\":\"5514\",\"operands\":[{\"id\":%s,\"name\":\"%s\"}]}",
                    this.params[0], this.params[1]);
            if (this.params[1].equals("OptimizationOff")) {
                output = String.format(
                        "{\"accountId\":\"5514\",\"operands\":[{\"id\":%s,\"bidOptimizationType\":\"%s\"}]}",
                        this.params[0], "NONE");
            } else if (this.params[1].equals("OptimizationOn")) {
                output = String.format(
                        "{\"accountId\":\"5514\",\"operands\":[{\"id\":%s,\"bidOptimizationType\":\"%s\",\"bidOptimizationGoal\":\"%s\"}]}",
                        this.params[0], this.params[2], this.params[3]);
            }
            if (object_type.equals("/ads")) {
                output = String.format("{\"accountId\":\"5514\",\"operands\":[{\"id\":%s,\"bidAmount\":\"%s\"}]}",
                        this.params[0], this.params[1]);
            }
            params = new StringEntity(output);
        }
        request.addHeader("content-type", "application/json");
        request.addHeader("Authorization", "Bearer " + this.Access_Token);
        request.setEntity(params);

        HttpResponse response = httpClient.execute(request);

        BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer result = new StringBuffer();
        String line = "";
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }

        System.out.println("API Resonse :"+result.toString());
        jsonObject = new JSONObject(result.toString());

    } catch (Exception ex) {

        ex.printStackTrace();

    } finally {

    }
    return jsonObject;

}

Answer 3

Though this may not help you with precisely an existing HTTP call using the traditional HttpURLConnection. Yet an interesting way to achieve this in recent times is to use HTTP/2 Client and try out the latest introduced incubator module jdk.incubator.http form Java 9.

An easy way(quick-start) of mocking a POST call using the same is as follows :

1. Create a java-module within your project and define module-info.java as:

   module http.trial { 
       requires jdk.incubator.httpclient;
   }
   

2. Within the module create a package and a class named HttpPost with following content:

   import jdk.incubator.http.HttpRequest;
   import jdk.incubator.http.HttpClient;
   import jdk.incubator.http.HttpResponse;
   import java.io.IOException;
   import java.net.URI;
   import java.net.URISyntaxException;
   
   public class HttpPost {
   
     public static void main(String[] args) {
   
       // Request builder
       URI uri = null;
       try {
           uri = new URI("https://ads.line.me/api/v1.0/authority_delegations/get");
       } catch (URISyntaxException e) {
           e.printStackTrace();
       }
       HttpRequest.BodyProcessor bodyProcessor = HttpRequest.BodyProcessor.fromString("{\"operands\":[]}");
       HttpRequest request = HttpRequest.newBuilder().uri(uri)
                       .header("Content-Type", "application/json")
                       .header("Authorization", "Bearer 1djCb/mXV+KtryMxr6i1bXw")
                       .POST(bodyProcessor)
                       .build();
   
       // Client
       HttpClient httpClient = HttpClient.newBuilder().followRedirects(HttpClient.Redirect.ALWAYS).build();
       System.out.println(httpClient.version());
   
       // Response builder
       HttpResponse response = null;
       try {
           response = httpClient.send(request, HttpResponse.BodyHandler.asString());
       } catch (IOException | InterruptedException e) {
           e.printStackTrace();
       }
   
       System.out.println("StatusCode = " + response.statusCode());
       System.out.println("Response = " + response.body().toString());
     }
   }
   

Answer 4

OutputStreamWriter will buffer the output. After this line in your code:

writer.write(payload);

add this line

writer.flush();

I would expect that to fix your problem.

Answer 5

HTTP code 400 means a BAD REQUEST.

I can't access the endpoint you have shared but here is free online REST API which I am using for demonstrating ..

curl -X POST \
  https://jsonplaceholder.typicode.com/posts \
  -H 'cache-control: no-cache' \
  -H 'postman-token: 907bbf75-73f5-703f-c8b6-3e1cd674ebf7' \
  -d '{
        "userId": 100,
        "id": 100,
        "title": "main title",
        "body": "main body"
    }'

• -H = headers
• -d = data

Sample Run:

[/c]$ curl -X POST \
>   https://jsonplaceholder.typicode.com/posts \
>   -H 'cache-control: no-cache' \
>   -H 'postman-token: 907bbf75-73f5-703f-c8b6-3e1cd674ebf7' \
>   -d '{
>         "userId": 100,
>         "id": 100,
>         "title": "main title",
>         "body": "main body"
>     }'

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   258  100   150  100   108    147    106  0:00:01  0:00:01 --:--:--   192{
  "{\n        \"userId\": 100,\n        \"id\": 100,\n        \"title\": \"main title\",\n        \"body\": \"main body\"\n    }": "",
  "id": 101
}

Java Code for the same is as follows:

OkHttpClient client = new OkHttpClient();

MediaType mediaType = MediaType.parse("application/octet-stream");
RequestBody body = RequestBody.create(mediaType, "{\n        \"userId\": 100,\n        \"id\": 100,\n        \"title\": \"main title\",\n        \"body\": \"main body\"\n    }");
Request request = new Request.Builder()
  .url("https://jsonplaceholder.typicode.com/posts")
  .post(body)
  .addHeader("cache-control", "no-cache")
  .addHeader("postman-token", "e11ce033-931a-0419-4903-ab860261a91a")
  .build();

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

Another example of calling REST POST call with data ..

User user = new User();
user.setFirstName("john");
user.setLastName("Maclane");

ResteasyClient client = new ResteasyClientBuilder().build();
ResteasyWebTarget target = client.target("URL");
Response response = target.request().post(Entity.entity(user, <MEDIATYPE>));
//Read output in string format
System.out.println(response.getStatus());
response.close(); 

Here is the what your code looks like when I update it with my endpoints and payload.

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Arrays;

public class TestClass {

    public static final String POST_URL = "https://jsonplaceholder.typicode.com/posts";

    public static final String POST_DATA = "{\"userId\": 100,\"id\": 100,\"title\": \"main title\",\"body\": \"main body\"}";

    public static void main(String[] args) throws Exception {
        String[] details = {};
        System.out.println(Arrays.toString(details));

        URL line_api_url = new URL(POST_URL);
        String payload = POST_DATA;

        HttpURLConnection linec = (HttpURLConnection) line_api_url
                .openConnection();
        linec.setDoInput(true);
        linec.setDoOutput(true);
        linec.setRequestMethod("POST");
        linec.setRequestProperty("Content-Type", "application/json");
        linec.setRequestProperty("Authorization", "Bearer "
                + "1djCb/mXV+KtryMxr6i1bXw");

        OutputStreamWriter writer = new OutputStreamWriter(
                linec.getOutputStream(), "UTF-8");
        writer.write(payload);

        BufferedReader in = new BufferedReader(new InputStreamReader(
                linec.getInputStream()));
        String inputLine;

        while ((inputLine = in.readLine()) != null)
            System.out.println(inputLine);
        in.close();
    }
}

In nutshell, check the API documentation and ensure the request payload is of correct format as 400 means BAD REQUEST.

Answer 6

It’s a 400 error, which means Bad Request. Please check this link below.

How to find out specifics of 400 Http error in Java?