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How do I make async http get requests in Java?

I wrote a program where I call many http get request. It takes like half a minute till all the get requests are done but it needs to be done within a second, this can be achieved with calling this method asynchronously, right? But how?
This is what my get request looks like:
public static String dataRequest(String link) throws IOException {
URL url = new URL(link);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Accept", "application/json");
if (conn.getResponseCode() != 200) {
throw new RuntimeException("Failed : HTTP Error code : " + conn.getResponseCode());
}
InputStreamReader in = new InputStreamReader(conn.getInputStream());
BufferedReader br = new BufferedReader(in);
String output;
String result = "";
while ((output = br.readLine()) != null) {
result += output;
}
conn.disconnect();
return result;
}
I tried using RxJava but I couldn't get it to work at all. I'm in a Maven JavaFx project. This method is in my getData class.

You can try using thread with ForkJoinPool
For example -> https://www.baeldung.com/java-fork-join

How to pass Form data variables to the rest api call from stand alone java code

I got a situation to test the REST API's Delete call through Java code. I need to pass Form Data with 2 variables as below screenshot to the api request. someone please route me how to do that..
try {
URL url = new URL("http://localhost:8999/testsource");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("DELETE");
conn.setRequestProperty("Accept", "*/*");
conn.setRequestProperty("session", "Cii2vEBZDplu5fI9JNXiM5");
if (conn.getResponseCode() != 200) {
throw new RuntimeException("Failed : HTTP error code : " + conn.getResponseCode());
}
BufferedReader br = new BufferedReader(new InputStreamReader((conn.getInputStream())));
String output;
System.out.println("Output from Server .... \n");
while ((output = br.readLine()) != null) {
System.out.println(output);
}
conn.disconnect();
} catch (Exception e) {
e.printStackTrace();
}

Your question isn't very clear but I'll make an attempt to answer it based on the assumption that your form data contains two fields which are:
id
permanentDelete
String data = "id=the-id-goes-here&permanentDelete=yes-or-no-goes-here";
byte[] bytesToSend = data.getBytes(StandardCharsets.UTF_8);
OutputStream outputStream = conn.getOutputStream();
outputStream.write(bytesToSend);

Java Post Connection Using Try with Resources

I want to implement the code for handling POST requests using try with resources.
Following is my code:
public static String sendPostRequestDummy(String url, String queryString) {
log.info("Sending 'POST' request to URL : " + url);
log.info("Data : " + queryString);
BufferedReader in = null;
HttpURLConnection con = null;
StringBuilder response = new StringBuilder();
try{
URL obj = new URL(url);
con = (HttpURLConnection) obj.openConnection();
// add request header
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", "Mozilla/5.0");
con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
con.setRequestProperty("Content-Type", "application/json");
// Send post request
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(queryString);
wr.flush();
wr.close();
int responseCode = con.getResponseCode();
log.info("Response Code : " + responseCode);
if (responseCode >= 400)
in = new BufferedReader(new InputStreamReader(con.getErrorStream()));
else
in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
}catch(Exception e){
log.error(e.getMessage(), e);
log.error("Error during posting request");
}
finally{
closeConnectionNoException(in,con);
}
return response.toString();
}
I have the following concerns for the code:
How to introduce conditional statements in try with resources for the above scenario?
Is there a way to pass on the connection in try with resources? (It can be done using nested try-catch blocks since URL and HTTPConnection is not AutoCloseable, which itself is not a compliant solution)
Is using try with resources for the above problem is a better approach?

Try this.
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
try (AutoCloseable conc = () -> con.disconnect()) {
// add request headers
try (DataOutputStream wr = new DataOutputStream(con.getOutputStream())) {
wr.writeBytes(queryString);
}
int responseCode = con.getResponseCode();
try (InputStream ins = responseCode >= 400 ? con.getErrorStream() : con.getInputStream();
BufferedReader in = new BufferedReader(new InputStreamReader(ins))) {
// receive response
}
}
() -> con.disconnect() is a lambda expression which execute con.disconnect() at finally stage of the try statement.

1: You can use conditional statements inside try with resources statement also. Unfortunately you have to define new variable for this block and cannot use a predefined variable. ( variable in in your code)
try (BufferedReader in = (responseCode >= 400 ? new BufferedReader(new InputStreamReader(con.getErrorStream())) : new BufferedReader(new InputStreamReader(con.getInputStream())))) {
// your code for getting string data
}
2: I'm not sure HttpUrlConnection is AutoCloseable, So it might be a good idea to call the disconnect() yourself. I'm open to any suggestion on this one.
3: try with resources will definitely help you in managing the resources. But if you're confident that you're releasing the resources properly after use, then your code is fine.

Response codes from Java.net.Url conection - Rest Webservice Client

I am using Java.Net.URL for making a Rest webservice call.
using the below example code.
URL url = new URL("UrlToConnect");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json");
String input = "{\"qty\":100,\"name\":\"iPad 4\"}";
OutputStream os = conn.getOutputStream();
os.write(input.getBytes());
os.flush();
if (conn.getResponseCode() != HttpURLConnection.HTTP_CREATED) {
throw new RuntimeException("Failed : HTTP error code : "
+ conn.getResponseCode());
}
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
System.out.println("Output from Server .... \n");
while ((output = br.readLine()) != null) {
System.out.println(output);
}
conn.disconnect();
i am trying to capture response code from this webservice call. I observed that Even after putting a wrong URL i am getting 200 response code from the connection. Please suggest a way by which i can capture response codes 200 , 201 and 202.
Thanks.

Google Translate Api error 414 (Request-URI Too Large) java

In official documentation of Google Translate Api for Java it says that we can use post-method to send more than 2K characters. https://developers.google.com/translate/v2/using_rest
However when I try to translate text more than 2k length I get error 414 (Request-URI Too Large).
StringBuilder sb = new StringBuilder();
HttpURLConnection connection = null;
try {
URL url = new URL("https://www.googleapis.com/language/translate/v2");
String urlParameters = "key=" + apiKey + "&source=" + shortLang1 +
"&target=" + shortLang2 + "&q=" + URLEncoder.encode(lyrics, "UTF-8");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoInput(true);
connection.setDoOutput(true);
connection.setUseCaches (false);
connection.addRequestProperty("X-HTTP-Method-Override", "GET");
DataOutputStream wr = new DataOutputStream (connection.getOutputStream ());
wr.writeBytes (urlParameters);
wr.flush ();
wr.close ();
BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
if (connection.getResponseCode() != 200) {
return null;
}
String line;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
reader.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
}
UPDATE: I got it, the code above is right. Finally I realize that I got this error not from Google Translate service but from my proxy on Google App Engine.

What the document you linked to is saying is that you use the POST method and you put the parameters into the request body ... not the request URL.
Reference:
How are parameters sent in an HTTP POST request?