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:

[[email protected], 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?

hard guess: but try replacing this BufferedReader in = new BufferedReader(new InputStreamReader(linec.getInputStream())); with BufferedReader in = new BufferedReader(new InputStreamReader(linec.getInputStream(), Charset.forName("UTF-8"))); — Vikas Prasad
– Vikas Prasad, Commented Sep 21, 2017 at 3:29
Also if some authentication is there, might be calling linec.connect(); before using OutputStreamWriter will help. linec.disconnect() at the end to disconnect — Vikas Prasad
– Vikas Prasad, Commented Sep 21, 2017 at 3:42

JRG · Accepted Answer · 2017-09-21 16:53:43Z

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.

SaAn · Accepted Answer · 2017-09-21 02:58:38Z

2

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?

answered Sep 21, 2017 at 2:58

SaAn

4526 silver badges23 bronze badges

Comments

RajSharma · Accepted Answer · 2017-09-26 07:12:59Z

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;

}

Mike · Accepted Answer · 2017-09-21 22:12:08Z

0

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.

answered Sep 21, 2017 at 22:12

Mike

362 bronze badges

Comments

Naman · Accepted Answer · 2017-09-25 16:46:33Z

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 :

Create a java-module within your project and define module-info.java as:
```
module http.trial { 
    requires jdk.incubator.httpclient;
}
```

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());
  }
}

Rajiv Singh · Accepted Answer · 2019-04-23 05:07:59Z

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)

}

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