I have many rest controllers in my project (developed with spring MVC) and i would like to make them communicate between each other.
what's the best way to make two spring REST controllers exchange messages ?
Supposed you have 2 controllers:
#RestController
#RequestMapping("/first")
public class FirstController(){
// your code here
}
and
#RestController
#RequestMapping("/second")
public class SecondController(){
// supposed this is your FirstController url.
String url = "http://localhost:8080/yourapp/first";
// create request.
HttpClient client = HttpClientBuilder.create().build();
HttpGet request = new HttpGet(url);
// execute your request.
HttpResponse response = client.execute(request);
// do whatever with the response.
}
For reference, have a look at this: http://www.mkyong.com/java/apache-httpclient-examples/
Used library: https://hc.apache.org/httpcomponents-client-ga/
Related
I have a client application requesting a list of channels from a webservice. Is it possible to take the "response" from the web service and store it in an ArrayList?
Meaning if I wanted to store a list of channels for example, it would normally come from the web service as a response, typically from ResponseBuilder.
And I want to store it in an ArrayList from the client, like List.
How would I go about doing that?
You can use TypeReference to instantiate your Channel object list, here is an example:
import com.fasterxml.jackson.core.type.TypeReference;
public class ChannelClient {
public void getChannels() {
Response serviceResponse = client.target("http://your_service_url/channels/").
request(MediaType.APPLICATION_JSON).get(Response.class);
String responseString = serviceResponse.readEntity(String.class);
List<Channel> list = new ObjectMapper().readerFor(new TypeReference<List<Channel>>() {
}).readValue(responseString);
}
}
Make sure to have Jersey JSON Jackson jar in your dependencies, you can get it from here
https://mvnrepository.com/artifact/org.glassfish.jersey.media/jersey-media-json-jackson/2.26-b07
EDIT: In case you want to consume MediaType.TEXT_PLAIN response, you will just change the request method argument to your specified type like this:
Response serviceResponse = client.target("http://your_service_url/channels/").
request(MediaType.TEXT_PLAIN).get(Response.class);
I am trying to implement a rest web service using Apache CXF and I want to return list of object as a response from server. So i have used generic entity to wrap my list on a server and everything is fine when I enter path from browser. It prints XML representation of object because I have used Jackson JAX-B but when i try to use JAX-RS client. I am getting an exception.
Exception in thread "main" javax.ws.rs.client.ResponseProcessingException: Problem with reading the data, class XYZ, ContentType: /.
at org.apache.cxf.jaxrs.impl.ResponseImpl.reportMessageHandlerProblem(ResponseImpl.java:433)
at org.apache.cxf.jaxrs.impl.ResponseImpl.doReadEntity(ResponseImpl.java:378)
at org.apache.cxf.jaxrs.impl.ResponseImpl.readEntity(ResponseImpl.java:325)
at org.apache.cxf.jaxrs.impl.ResponseImpl.readEntity(ResponseImpl.java:313)
at XYZ.ABC()
at XYZ.ABC()
Caused by: javax.ws.rs.core.NoContentException: Message body is empty
at org.apache.cxf.jaxrs.provider.AbstractJAXBProvider.reportEmptyContentLength(AbstractJAXBProvider.java:276)
at org.apache.cxf.jaxrs.provider.JAXBElementProvider.readFrom(JAXBElementProvider.java:166)
at org.apache.cxf.jaxrs.utils.JAXRSUtils.readFromMessageBodyReader(JAXRSUtils.java:1325)
at org.apache.cxf.jaxrs.impl.ResponseImpl.doReadEntity(ResponseImpl.java:369)
... 4 more
I have written a following client code to get data from server
final Client client = ClientBuilder.newClient();
WebTarget webTarget = client.target(URI.create(PATH));
Response response = webTarget.request(MediaType.APPLICATION_XML).get();
List<ABC> obj = response.readEntity(new GenericType<List<ABC>> (ABC.class){});
But Apart from it I have tried many code to implement CXF client and get data from server but I am getting a same exception almost all the time. I have tried JAXRSCLIENTFactory also to implement client but the same exception.
I ran into the same problem in unmarshalling using the CXF client. Here is how I did it:
Read the response into a String.
Used Gson to convert from string to list of objects.
Note: You will need a wrapper class for your list of objects.
Example:
If the server returns a list of products, Here is how to unmarshall the list:
Create a wrapper class
public class ProductList {
private List<Product> products;
public List<Product> getProducts() {
return products;
}
public void setProducts(List<Product> products) {
this.products = products;
}
}
Code to unmarshall
String responseBody = response.readEntity(String.class);
ProductList productList = new Gson().fromJson(responseBody, ProductList.class);
if(productList.getProducts() != null)
return productList.getProducts();
Please ignore the spelling mistake, I cannot copy code so I have typed the whole thing and changed name of controller and method.
WEB API 2
Controller:
// Controller name is Test
public HttpResponseMessage Method1(int param1) // Post method
{
// return string
}
If I create an object of controller in test case then it is working fine. But if I want to test in localhost using following code:
Unit Test:
public void Method1Test()
{
HttpResponseMessage response;
HttpConfiguration config = new HttpConfiguration();
config.Routes.MapHttpRoute("DefaultApi", "api/{controller}/{id}");
HttpServer server = new HttpServer(config);
using(var client = new HttpClient(server))
{
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "http://localhost:5022/api/test?param1=1");
request.Content = new ObjectContent<int>(param1, new JsonMediaTypeFormatter());
response = client.SendAsync(request, CancellationToken.None).Result;
};
Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);
}
Now, my test case is failing. I used the same code in different project and it worked. May be it is the way I am trying to call Post method. Is this the right way to call post method with Int parameter in URL?
In help page, under API column it shows:
POST api/test/param1={param1}
Also I have put some stop point in actual service I am cursor is not stopping at that point. Why?
If I want to call the same service from browser, what URL should I pass? Is it -
http://localhost:5022/api/test?param1=1
Or something else?
I figured it out. Following is the correct unit test method but this has some extra information which I have not provided earlier i.e., passing object as an input for the service.
private void Method1Test(ObjectClass obj)
{
HttpResponseMessage response = null;
HttpConfiguration config = new HttpConfiguration();
config.Routes.MapHttpRoute("DefaultApi", "api/{controller}/{id}");
HttpServer server = new HttpServer(config);
using (var client = new HttpClient(server))
{
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "http://localhost:5022/api/test/1");
request.Content = new ObjectContent<ObjectClass>(obj, new JsonMediaTypeFormatter());
response = client.SendAsync(request, CancellationToken.None).Result;
};
Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);
}
So the correct URL that I was looking for was
http://localhost:5022/api/test/1
Sorry, It took long to post this answer. This method is working like a charm for more then 2 years.
I am working on some web servers and I have to sent some data to the web service and get back a status code.. I am thinking maybe this should be a POST and not a GET but I would like to hear from all the pros out on the internet.
Here is my client code using Spring RESTTemplate
vars.put("lastName", "JOHN");
vars.put("firstName", "SMITH");
vars.put("middleInitial", "");
vars.put("socialSecurityNumber", "111-11-1111");
vars.put("Type","A");
vars.put("FileNumber","");
vars.put("EISNumber","");
String jsonreturn = restTemplate.getForObject("http://" + mRESTServer.getHost() + ":8080/services/api/checkstatus", String.class, vars);
Now here is my service side code (Spring MVC RESTful service). I would think all the fields I entered in the client would be in the ModelMap object but its not
#RequestMapping(value = "/checkstatus", method = RequestMethod.get)
#ResponseBody
public ResponseEntity<String> getCheckEnrollStatus(ModelMap model) throws ResourceNotFoundException
{
logger.debug("Looking for Status: " + model.toString());
}
So I have two questions:
1) Should I change the GET to a POST due to senting alot of data to the server?
2) If I leave it as a get why is my ModelMap emply?
Please help me out
For your ModelMap to be populated you probably need to annotate it with #RequestBody.
As the comment has pointed out you can't have a request body with a GET as per the specification. So you would either need to make the parameters part of the URL and use get or convert to POST.
Though POST seems to not fit with the purpose of your call.
Normally I'd say this should be a GET, but I noticed you have socialSecurityNumber as one of your parameters. You definitely do NOT want that to be part of your URL. Check out RFC 2616 section 15.1.3
Authors of services which use the HTTP protocol SHOULD NOT use GET based forms for the submission of sensitive data, because this will cause this data to be encoded in the Request-URI. Many existing servers, proxies, and user agents will log the request URI in some place where it might be visible to third parties. Servers can use POST-based form submission instead
Do a POST.
get as it is not changing anything onserver just returning data here is the spec.
Use request parameters like this
#RequestMapping(value = "/checkstatus", method = RequestMethod.get)
#ResponseBody
public ResponseEntity<String> getCheckEnrollStatus(#RequestParam final Long id)
or uri parameters, like
#RequestMapping(value = "/checkstatus/{id}", method = RequestMethod.get)
#ResponseBody
public ResponseEntity<String> getCheckEnrollStatus(#PathVariable final Long id) throws ResourceNotFoundException
{
I am currently developing a web app which should do restful service calls to existing web service api.
What I have is the base URL and the API names.
Any help on how do I start working on it?
I suppose I need to use httpbuilder for the base url I have, then followed by /api name. But how do I test it on grails if its working?
When I paste the base url on the browser it does return some xml information, so what I need is to do it on grails instead.
XML response when I paste the url through browser
<ns1:createNewUserResponse>
<userId>21</userId>
</ns1:createNewUserResponse>
So I need to be able to get this response through my web-app (grails) instead of pasting it on the browser.
EDIT*
this is a good example I found useful
#Grab(group='org.codehaus.groovy.modules.http-builder', module='http-builder', version='0.5.0-RC2' )
import groovyx.net.http.*
import static groovyx.net.http.ContentType.*
import static groovyx.net.http.Method.*
def http = new HTTPBuilder( 'http://ajax.googleapis.com' )
// perform a GET request, expecting JSON response data
http.request( GET, JSON ) {
uri.path = '/ajax/services/search/web'
uri.query = [ v:'1.0', q: 'Calvin and Hobbes' ]
headers.'User-Agent' = 'Mozilla/5.0 Ubuntu/8.10 Firefox/3.0.4'
// response handler for a success response code:
response.success = { resp, json ->
println resp.statusLine
// parse the JSON response object:
json.responseData.results.each {
println " ${it.titleNoFormatting} : ${it.visibleUrl}"
}
}
// handler for any failure status code:
response.failure = { resp ->
println "Unexpected error: ${resp.statusLine.statusCode} : ${resp.statusLine.reasonPhrase}"
}
}
but i do not understand the query part and how do I alter it to my need?
the URL I have contains credential of username and password, the response should return a securityToken which I need to get it out from the results. Any help would be greatly appreciated!
You can start with groovy-wslite, it provides both SOAP and REST webservice clients.
To make a call to a resfull service look at Groovy HttpBuidler - http://groovy.codehaus.org/HTTP+Builder