CODEWITHSUNDEEP
javajsoncurl
woopi
woopi

Reputation: 13

How to replicate curl command using java?

Precisely said I want to perform below curl action which returns json with java:

curl -H 'Client-ID: ahh_got_ya' -X GET 'https://api.twitch.tv/helix/streams'

This works just fine in linux shell.

below is my script trying to do above curl using java json:

{String urly = "https://api.twitch.tv/helix/streams";
    URL obj = new URL(urly);
    HttpURLConnection con = (HttpURLConnection) obj.openConnection();

    con.setRequestMethod("GET");
    con.setRequestProperty("Content-Type","application/json");
    con.setRequestProperty("Client-ID","Ahh_got_ya");


    con.setDoOutput(true);
    DataOutputStream wr = new DataOutputStream(con.getOutputStream());
    wr.writeBytes("");
    wr.flush();
    wr.close();

    int responseCode = con.getResponseCode();
    System.out.println("Response Code : " + responseCode);

    BufferedReader iny = new BufferedReader(
    new InputStreamReader(con.getInputStream()));
      String output;
      StringBuffer jsonres = new StringBuffer();

      while ((output = iny.readLine()) != null) {
          jsonres.append(output);
      }
    iny.close();

    //printing result from response
    System.out.println(response.toString());
}

I am getting: java.io.FileNotFoundException: https://api.twitch.tv/helix/streams Response Code : 404

All replies are much appreciated.

Upvotes: 0

Views: 1000

Answers (2)

eDog
eDog

Reputation: 173

Almost there! You are doing a GET call and do not need to make the connection writeable -- since you are not going to post. You need to remove that section there. Also - to get exactly what your curl call is doing, remove the Content-Type - since it is not used in the curl call. So your code adjusted should be:

{
    String urly = "https://api.twitch.tv/helix/streams";
    URL obj = new URL(urly);
    HttpURLConnection con = (HttpURLConnection) obj.openConnection();

    //only 2 headers from cURL call
    con.setRequestMethod("GET");
    con.setRequestProperty("Client-ID","Ahh_got_ya");

    int responseCode = con.getResponseCode();
    System.out.println("Response Code : " + responseCode);

    BufferedReader iny = new BufferedReader(
    new InputStreamReader(con.getInputStream()));
      String output;
      StringBuffer jsonres = new StringBuffer();

      while ((output = iny.readLine()) != null) {
          jsonres.append(output);
      }
    iny.close();

    //printing result from response
    System.out.println(response.toString());
}

The reason for the 404 is if your request does not match what the service endpoint is expecting. Sending a POST request or other types of non-expect stuff will result is a request that does not match. Remove the extra output stuff and give it a go!

Upvotes: 1

Joeri_Damian
Joeri_Damian

Reputation: 80

The way you state your question is a bit weird. But I assume you want to let a Java program make a cURL call of a JSON file. Now your linux terminal talks BASH not Java. So here is step 1.

You have to use a library.
Options are java.net.URL and/or java.net.URLConnection.

So #include one or either of those.

URL url = new URL("https://api.twitch.tv/helix/streams");

try (BufferedReader reader = new BufferedReader(new 
InputStreamReader(url.openStream(), "UTF-8"))) {
    for (String line; (line = reader.readLine()) != null;) {
        System.out.println(line);
    }
}

https://docs.oracle.com/javase/tutorial/networking/urls/readingWriting.html

Another thing you could mean is you want Java to generate JSON and access cURL trough Bash which isn't something I would advise anyone to do. If you feel like you have to it would be something like this. 

public class ExecuteShellCommand {

public String executeCommand(String command) {

With the string set to cURL

Upvotes: 0

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