How to get array from Http Post in a Restful Web Service?

Question

I have a controller for AngularJS Framework. I use a Http Post Request to send an array to a server. How to get this array in a java method?

This is my controller

var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope, $http) {

var indici = new Array();

indici.push(1);
indici.push(2);

$http.post("http://localhost:8080/SistemiDistribuiti/rest/Point/Trovati", indici, {
              headers: { 'Content-Type': 'application/json' }
            }).success(function(receivedData, status) {
                $scope.someData = receivedData;
            });

And this is my java class but i don't know how to get my array.

import javax.ws.rs.Path;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.POST;
import javax.ws.rs.Consumes;

@Path("Point")
public class PointService {


@POST
@Path("Trovati")
@Consumes(MediaType.APPLICATION_JSON)
public void RetrieveData() {
     //how print my array?
}

Answer 1

You have to use @GET as below:

@GET
@Path("/blabla")
public Response receiveListOfStrings(@QueryParam("list") final List<String> list){
    log.info("receieved list of size="+list.size());
    return Response.ok().build();
}

And request:

GET http://example.com/services/echo?list=balbla&list=asdasd&list=BYE

Post doesn't support this. Or you can use @PUT with complex type.

Put example:

@PUT
public Response putExample(MyObject obj) {
    log.info("receieved list of size="+obj.getList().size());
    return Response.ok().build();
}

In this put example you can see I used a custom MyObject Here's its codes:

public class MyObject{

    private List<String> list = new ArrayList<String>();

    public List<String> getList(){
        return list;
    }

    public void setList( List<String> list ){
        this.list = list;
    }

    @Override
    public String toString(){
        return "MyObject [list=" + list + "]";
    }

}

As you can see there's a list property in your MyObject class. So you can print anything by calling getList as my example above.

Answer 2

I agree with @lex82, you don't send the payload within your request. See the documentation for $http.post: https://docs.angularjs.org/api/ng/service/$http#post. Be sure to understand what promises are and how they are used within the HTTP support of Angular.

Here is a sample:

var dataToSend = {
  // some JSON data
};
$http.post("/some-url", dataToSend, {
  headers: { 'Content-Type': 'application/json' }
}).success(function(receivedData, status) {
        $scope.someData = receivedData;
});

That said, you say that you don't receive the data on the server. The first to do is to check your raw request. This can be done within Chrome using the Chrome Developer Tools (CRTL + SHIFT + i). This will give you access to a Network tab containing every request. Click on the request corresponding to your AJAX request and check if there is a payload in your request. If so, it's a problem on your server side within your JAXRS application.

Do you some exceptions within your JAXRS application?

Hope it helps you, Thierry

Answer 3

Apache has an http library that can be used to make various http requests.

<dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.3.2</version>
  </dependency>

You will also need a library that can be used to transform your json objects into Java object. Google has created a library called gson that I will use in my example.

<dependency>
      <groupId>com.google.code.gson</groupId>
      <artifactId>gson</artifactId>
      <version>2.2.4</version>
  </dependency>

You are also going to have to create a Java object that represents your data. This will be used to map your json object to a java object or "pojo". I'm not sure what your JSON objects look like, but I'm going to use a generic example called Response.

public class Response
{
    private List<Example> examples;
    private double total;
    private String someString;

    public QuoteResponse()
    {
        super();
    }

    public List<Examples> getExamples() {
        return examples;
    }

    public void setExamples(List<Examples> examples)
    {
        this.examples = examples;
    }

    public double getTotal() {
        return total;
    }

    public void setTotal(double total) {
        this.total = total;
    }

    public String getSomeString() {
        return someString;
    }

    public void setPrint_type(String someString) {
        this.someString = someString;
    }
}

Your java object has to have the same number of fields with the same type and same name as your JSON object.

Next, you will have to write a function that calls your angular api. See an example below:

public Response getJsonData()
{
    params = new Params();
    String url = "https://www.yoururl.com/controller/function_you_want;
    Response response = null;
    HttpGet httpGet = new HttpGet(url);

    try
    {
        response = httpClient.execute(httpGet);

        //check to make sure that everything is ok
        if(response.getStatusLine().getStatusCode() == 200)
        {
            entity = response.getEntity();
            jsonResponse = EntityUtils.toString(entity);
            JsonNode root = mapper.readTree(jsonResponse).get("result");
            response = gson.fromJson(root.toString(),Response.class);
        }
    }
    catch (IOException e)
    {
        e.printStackTrace();
    }

    return response;
}

That's about it. Let me know if you have any questions.