How to POST JSON request using Apache HttpClient? - java

I have something like the following:
final String url = "http://example.com";
final HttpClient httpClient = new HttpClient();
final PostMethod postMethod = new PostMethod(url);
postMethod.addRequestHeader("Content-Type", "application/json");
postMethod.addParameters(new NameValuePair[]{
new NameValuePair("name", "value)
});
httpClient.executeMethod(httpMethod);
postMethod.getResponseBodyAsStream();
postMethod.releaseConnection();
It keeps coming back with a 500. The service provider says I need to send JSON. How is that done with Apache HttpClient 3.1+?


Apache HttpClient doesn't know anything about JSON, so you'll need to construct your JSON separately. To do so, I recommend checking out the simple JSON-java library from json.org. (If "JSON-java" doesn't suit you, json.org has a big list of libraries available in different languages.)
Once you've generated your JSON, you can use something like the code below to POST it
StringRequestEntity requestEntity = new StringRequestEntity(
JSON_STRING,
"application/json",
"UTF-8");
PostMethod postMethod = new PostMethod("http://example.com/action");
postMethod.setRequestEntity(requestEntity);
int statusCode = httpClient.executeMethod(postMethod);
Edit
Note - The above answer, as asked for in the question, applies to Apache HttpClient 3.1. However, to help anyone looking for an implementation against the latest Apache client:
StringEntity requestEntity = new StringEntity(
JSON_STRING,
ContentType.APPLICATION_JSON);
HttpPost postMethod = new HttpPost("http://example.com/action");
postMethod.setEntity(requestEntity);
HttpResponse rawResponse = httpclient.execute(postMethod);


For Apache HttpClient 4.5 or newer version:
CloseableHttpClient httpclient = HttpClients.createDefault();
HttpPost httpPost = new HttpPost("http://targethost/login");
String JSON_STRING="";
HttpEntity stringEntity = new StringEntity(JSON_STRING,ContentType.APPLICATION_JSON);
httpPost.setEntity(stringEntity);
CloseableHttpResponse response2 = httpclient.execute(httpPost);
Note:
1 in order to make the code compile, both httpclient package and httpcore package should be imported.
2 try-catch block has been ommitted.
Reference:
appache official guide
the Commons HttpClient project is now end of life, and is no longer
being developed. It has been replaced by the Apache HttpComponents
project in its HttpClient and HttpCore modules


As mentioned in the excellent answer by janoside, you need to construct the JSON string and set it as a StringEntity.
To construct the JSON string, you can use any library or method you are comfortable with. Jackson library is one easy example:
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
ObjectMapper mapper = new ObjectMapper();
ObjectNode node = mapper.createObjectNode();
node.put("name", "value"); // repeat as needed
String JSON_STRING = node.toString();
postMethod.setEntity(new StringEntity(JSON_STRING, ContentType.APPLICATION_JSON));


I use JACKSON library to convert object to JSON and set the request body like below. Here is full example.
try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
HttpPost httpPost = new HttpPost("https://jsonplaceholder.typicode.com/posts");
Post post = new Post("foo", "bar", 1);
ObjectWriter ow = new ObjectMapper().writer();
String strJson = ow.writeValueAsString(post);
System.out.println(strJson);
StringEntity strEntity = new StringEntity(strJson, ContentType.APPLICATION_JSON);
httpPost.setEntity(strEntity);
httpPost.setHeader("Content-type", "application/json");
try (CloseableHttpResponse response = httpclient.execute(httpPost)) {
System.out.println(response.getCode() + " " + response.getReasonPhrase());
HttpEntity entity = response.getEntity();
String result = EntityUtils.toString(entity);
System.out.println(result);
EntityUtils.consume(entity);
} catch (ParseException e) {
e.printStackTrace();
}
} catch (IOException e) {
System.out.println(e.getMessage());
}

Related

Send HTTPS request with JSON through Java [duplicate]

I would like to make a simple HTTP POST using JSON in Java.
Let's say the URL is www.site.com
and it takes in the value {"name":"myname","age":"20"} labeled as 'details' for example.
How would I go about creating the syntax for the POST?
I also can't seem to find a POST method in the JSON Javadocs.

Here is what you need to do:
Get the Apache HttpClient, this would enable you to make the required request
Create an HttpPost request with it and add the header application/x-www-form-urlencoded
Create a StringEntity that you will pass JSON to it
Execute the call
The code roughly looks like (you will still need to debug it and make it work):
// #Deprecated HttpClient httpClient = new DefaultHttpClient();
HttpClient httpClient = HttpClientBuilder.create().build();
try {
HttpPost request = new HttpPost("http://yoururl");
StringEntity params = new StringEntity("details={\"name\":\"xyz\",\"age\":\"20\"} ");
request.addHeader("content-type", "application/x-www-form-urlencoded");
request.setEntity(params);
HttpResponse response = httpClient.execute(request);
} catch (Exception ex) {
} finally {
// #Deprecated httpClient.getConnectionManager().shutdown();
}

You can make use of Gson library to convert your java classes to JSON objects.
Create a pojo class for variables you want to send
as per above Example
{"name":"myname","age":"20"}
becomes
class pojo1
{
String name;
String age;
//generate setter and getters
}
once you set the variables in pojo1 class you can send that using the following code
String postUrl = "www.site.com";// put in your url
Gson gson = new Gson();
HttpClient httpClient = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(postUrl);
StringEntity postingString = new StringEntity(gson.toJson(pojo1));//gson.tojson() converts your pojo to json
post.setEntity(postingString);
post.setHeader("Content-type", "application/json");
HttpResponse response = httpClient.execute(post);
and these are the imports
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.HttpClientBuilder;
and for GSON
import com.google.gson.Gson;

#momo's answer for Apache HttpClient, version 4.3.1 or later. I'm using JSON-Java to build my JSON object:
JSONObject json = new JSONObject();
json.put("someKey", "someValue");
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
try {
HttpPost request = new HttpPost("http://yoururl");
StringEntity params = new StringEntity(json.toString());
request.addHeader("content-type", "application/json");
request.setEntity(params);
httpClient.execute(request);
// handle response here...
} catch (Exception ex) {
// handle exception here
} finally {
httpClient.close();
}

It's probably easiest to use HttpURLConnection.
http://www.xyzws.com/Javafaq/how-to-use-httpurlconnection-post-data-to-web-server/139
You'll use JSONObject or whatever to construct your JSON, but not to handle the network; you need to serialize it and then pass it to an HttpURLConnection to POST.

protected void sendJson(final String play, final String prop) {
Thread t = new Thread() {
public void run() {
Looper.prepare(); //For Preparing Message Pool for the childThread
HttpClient client = new DefaultHttpClient();
HttpConnectionParams.setConnectionTimeout(client.getParams(), 1000); //Timeout Limit
HttpResponse response;
JSONObject json = new JSONObject();
try {
HttpPost post = new HttpPost("http://192.168.0.44:80");
json.put("play", play);
json.put("Properties", prop);
StringEntity se = new StringEntity(json.toString());
se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
post.setEntity(se);
response = client.execute(post);
/*Checking response */
if (response != null) {
InputStream in = response.getEntity().getContent(); //Get the data in the entity
}
} catch (Exception e) {
e.printStackTrace();
showMessage("Error", "Cannot Estabilish Connection");
}
Looper.loop(); //Loop in the message queue
}
};
t.start();
}

Try this code:
HttpClient httpClient = new DefaultHttpClient();
try {
HttpPost request = new HttpPost("http://yoururl");
StringEntity params =new StringEntity("details={\"name\":\"myname\",\"age\":\"20\"} ");
request.addHeader("content-type", "application/json");
request.addHeader("Accept","application/json");
request.setEntity(params);
HttpResponse response = httpClient.execute(request);
// handle response here...
}catch (Exception ex) {
// handle exception here
} finally {
httpClient.getConnectionManager().shutdown();
}

I found this question looking for solution about how to send post request from java client to Google Endpoints. Above answers, very likely correct, but not work in case of Google Endpoints.
Solution for Google Endpoints.
Request body must contains only JSON string, not name=value pair.
Content type header must be set to "application/json".
post("http://localhost:8888/_ah/api/langapi/v1/createLanguage",
"{\"language\":\"russian\", \"description\":\"dsfsdfsdfsdfsd\"}");
public static void post(String url, String json ) throws Exception{
String charset = "UTF-8";
URLConnection connection = new URL(url).openConnection();
connection.setDoOutput(true); // Triggers POST.
connection.setRequestProperty("Accept-Charset", charset);
connection.setRequestProperty("Content-Type", "application/json;charset=" + charset);
try (OutputStream output = connection.getOutputStream()) {
output.write(json.getBytes(charset));
}
InputStream response = connection.getInputStream();
}
It sure can be done using HttpClient as well.

You can use the following code with Apache HTTP:
String payload = "{\"name\": \"myname\", \"age\": \"20\"}";
post.setEntity(new StringEntity(payload, ContentType.APPLICATION_JSON));
response = client.execute(request);
Additionally you can create a json object and put in fields into the object like this
HttpPost post = new HttpPost(URL);
JSONObject payload = new JSONObject();
payload.put("name", "myName");
payload.put("age", "20");
post.setEntity(new StringEntity(payload.toString(), ContentType.APPLICATION_JSON));

For Java 11 you can use the new HTTP client:
HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create("http://localhost/api"))
.header("Content-Type", "application/json")
.POST(ofInputStream(() -> getClass().getResourceAsStream(
"/some-data.json")))
.build();
client.sendAsync(request, BodyHandlers.ofString())
.thenApply(HttpResponse::body)
.thenAccept(System.out::println)
.join();
You can use publishers from InputStream, String, File. Converting JSON to a String or IS can be done with Jackson.

Java 11 standardization of HTTP client API that implements HTTP/2 and Web Socket, and can be found at java.net.HTTP.*:
String payload = "{\"name\": \"myname\", \"age\": \"20\"}";
HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder(URI.create("www.site.com"))
.header("content-type", "application/json")
.POST(HttpRequest.BodyPublishers.ofString(payload))
.build();
HttpResponse<String> response = client.send(request, BodyHandlers.ofString());

Java 8 with apache httpClient 4
CloseableHttpClient client = HttpClientBuilder.create().build();
HttpPost httpPost = new HttpPost("www.site.com");
String json = "details={\"name\":\"myname\",\"age\":\"20\"} ";
try {
StringEntity entity = new StringEntity(json);
httpPost.setEntity(entity);
// set your POST request headers to accept json contents
httpPost.setHeader("Accept", "application/json");
httpPost.setHeader("Content-type", "application/json");
try {
// your closeablehttp response
CloseableHttpResponse response = client.execute(httpPost);
// print your status code from the response
System.out.println(response.getStatusLine().getStatusCode());
// take the response body as a json formatted string
String responseJSON = EntityUtils.toString(response.getEntity());
// convert/parse the json formatted string to a json object
JSONObject jobj = new JSONObject(responseJSON);
//print your response body that formatted into json
System.out.println(jobj);
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}

I recomend http-request built on apache http api.
HttpRequest<String> httpRequest = HttpRequestBuilder.createPost(yourUri, String.class)
.responseDeserializer(ResponseDeserializer.ignorableDeserializer()).build();
public void send(){
ResponseHandler<String> responseHandler = httpRequest.execute("details", yourJsonData);
int statusCode = responseHandler.getStatusCode();
String responseContent = responseHandler.orElse(null); // returns Content from response. If content isn't present returns null.
}
If you want send JSON as request body you can:
ResponseHandler<String> responseHandler = httpRequest.executeWithBody(yourJsonData);
I higly recomend read documentation before use.

Java get latest GitHub release

I had tried to acess to GitHub via Java to get the latest release of a repository and I had found this and I tried to use it with this code:
String url = "https://github.com/:owner/:repo/releases/latest";
try {
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
HttpGet request = new HttpGet(url);
request.addHeader("content-type", "application/json");
HttpResponse result = httpClient.execute(request);
String json = EntityUtils.toString(result.getEntity(), "UTF-8");
System.out.println(json);
} catch (IOException ex) {
}
and the only thing I get as response is the HTML code of the website but I want the json response like you can see in the exaple response here.

Thanks for the Help!
Yea, it is right, you have to acess to api.github.com and you have to set Accept: application/vnd.github.v3+json

Java JSON Apache POST Parameters

So I've got this code:
HttpClient httpClient = new DefaultHttpClient();
try {
HttpPost request = new HttpPost("url");
StringEntity params = new StringEntity("stuff");
request.addHeader("content-type", "application/json");
//request.addHeader("Accept","application/json");
request.setEntity(params);
HttpResponse response = httpClient.execute(request);
//stuff
} catch (Exception ex) {
//stuff
} finally {
httpClient.getConnectionManager().shutdown();
}
I need to create a POST request which I can do with curl -X POST /groups/:group_id/members/add etc but I'm not sure how to add the /groups/ param to my code... I'm not super familiar with how to do this so any advice would be appreciated. Thanks!
EDIT 1: (SOLVED)
Have used the suggested code but would like some help with variables used in the string while remaining valid JSON format, if possible.
EDIT 2:
Using that method, can you show an example of how to add multiple users to that one StringEntity? So like user1 is "User1" and has the email "Email1" and user2 has "User2" and "Email2" etc

Just create a url string using the prams you have and pass it as argument to HttpPost()
DefaultHttpClient httpClient = new DefaultHttpClient();
String groupId = "groupId1";
String URL = "http://localhost:8080/"+groupId+"/members/add"
HttpPost postRequest = new HttpPost(
URL );
StringEntity input = new StringEntity("{\"name\":matt,\"from\":\"stackovefflow\"}");
input.setContentType("application/json");
postRequest.setEntity(input);
HttpResponse response = httpClient.execute(postRequest);
UPDATED
The input to StringEntity is a string whihc you can manipulate in any way.
You can define a method like
private createStringEntity(String name, String email){
return new StringEntity("{\"name\":\""+name+"\",\"email\":\""+email+"\"}");
}

The "/groups/..." part is not a parameter but a fraction of the url. I dont think this will work, because "url" is just a String, change it to this:
HttpPost request = new HttpPost("http://stackoverflow.com/groups/[ID]/members/add");

add json object to Java HttpGet request to C# WebApi

i'm trying to send json object from java client to C# WebApi, but the input parameter is null.
the java code:
ObjectMapper mapper = new ObjectMapper();
Gson gson = new Gson();
String json = gson.toJson(per);
HttpClient httpclient = new DefaultHttpClient();
List<NameValuePair> qparams = new ArrayList<NameValuePair>();
qparams.add(new BasicNameValuePair("person", json.toString()));
HttpGet httpPost = new HttpGet("http://naviserver.azurewebsites.net/api/Person/Get?" + URLEncodedUtils.format(qparams, "UTF-8"));
httpPost.setHeader("Accept", "application/json");
httpPost.setHeader("Content-type", "application/json");
httpPost.setHeader(
"Authorization",
"Bearer TokenRemovedBecauseUseless");
org.apache.http.HttpResponse httpResponse = httpclient.execute(httpPost);
the WebApi method:
public List<String> Get([FromUri]Person person)
{}
can someone tell me how to send json object?

The problem is that the WebApi is not expecting the person object in JSON format. By using FromUri with a complex object, it is expecting that the url with have a query parameter for each field in Person.
There is a nice example here about how it works.
Basically you will want your query parameters to look like this:
http://naviserver.azurewebsites.net/api/Person/Get?name=dave&age=30
and in Java:
qparams.add(new BasicNameValuePair("name", person.getName()));
qparams.add(new BasicNameValuePair("age", String.valueOf(person.getAge())));
If you want to send the person in JSON format, a better way would be to use a HTTP POST and set the JSON in the body. Then in the WebApi, your method would look like this:
public HttpResponseMessage Post([FromBody]Person person)
You will then also have to change your Java client to send a POST request.
HttpClient httpClient = HttpClientBuilder.create().build();
HttpPost httpPost = new HttpPost("http://naviserver.azurewebsites.net/api/Person");
Person person = new Person("dave", 30);
Gson gson = new Gson();
String json = gson.toJson(person);
StringEntity body = new StringEntity(json);
httpPost.setEntity(body);
HttpResponse response = httpClient.execute(httpPost);

Use Java to get Github repositories

I'm using the following code to send a http request to github.
String url = "https://api.github.com/repositories";
try {
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
HttpPost request = new HttpPost(url);
// StringEntity params = new StringEntity(body);
request.addHeader("content-type", "application/json");
// request.setEntity(params);
HttpResponse result = httpClient.execute(request);
String json = EntityUtils.toString(result.getEntity(), "UTF-8");
System.out.println(json);
} catch (IOException ex) {
}
I got output: {"message":"Not Found","documentation_url":"https://developer.github.com/v3"}
If use directly put "https://api.github.com/repositories" in browser, a lot of useful information will be shown. My question is how can I get the information I see when using browser by using Java.

You should use HttpGet instead of HttpPost. Just like your browser sends a GET request.

Categories