I'm in a project where you need to access a REST web service and would like to know which Java library is most commonly used to access this type of resource in an easy way.
I know that it's even possible to do everything in the hand using the Java standard classes, but I'm looking for something that simplifies the work a little, and also knows the market standard for it.
Another good option is JBoss RESTEasy . In addition to implementing the JAX-RS 2.0 Client standard (ie it is possible to make calls with the same code as @utluiz demonstrated for Jersey), the library has its own proxies-based API.
Sample documentation :
Client client = ClientFactory.newClient();
WebTarget target = client.target("http://example.com/base/uri");
ResteasyWebTarget rtarget = (ResteasyWebTarget)target;
SimpleClient simple = rtarget.proxy(SimpleClient.class);
client.putBasic("hello world");
Where SimpleClient is an annotated interface (can be even the same as the server):
public interface SimpleClient {
@PUT
@Path("basic")
@Consumes("text/plain")
void putBasic(String body);
// ... Demais métodos
}
Some other options besides the Jersey and RESTEasy
Finally, while this is not necessarily practical, you can always use raw HTTP APIs to consume REST services. HttpURLConnection , Apache HttpClient , etc. This gives you more control in exchange for much more extensive code (and susceptible to errors).
For a design Open Source / article that I am writing together with a colleague, we have decided to code a method that upload images to Facebook on the POST with multipart / form-data encode) and compare with the code of a specialized library RestFB ). You can see the difference in size and complexity of the publicarRestFB vs publicarGraphAPI to feel the drama.
I can not say it is the most widely used framework (this is debatable), but I use the Jersey , implementation API reference JAX-RS. It implements both the server part and the client part.
See an example of using the Client API :
Client client = ClientBuilder.newClient();
WebTarget target = client.target("http://localhost:9998").path("resource");
Form form = new Form();
form.param("x", "foo");
form.param("y", "bar");
MyJAXBBean bean =
target.request(MediaType.APPLICATION_JSON_TYPE)
.post(Entity.entity(form,MediaType.APPLICATION_FORM_URLENCODED_TYPE),
MyJAXBBean.class);
I use the org.apache.httpcomponents library
If you use maven in your project, here are the dependencies
<!-- Httpclient: http://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient/4.3 -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.3</version>
</dependency>
<!-- Common-HttpClient: http://mvnrepository.com/artifact/commons-httpclient/commons-httpclient/3.1 -->
<dependency>
<groupId>commons-httpclient</groupId>
<artifactId>commons-httpclient</artifactId>
<version>3.1</version>
</dependency>
Usage example
public String doRequestPost(String aRota) throws HttpException, IOException {
HttpClient httpClient = new HttpClient();
PostMethod httpPost = new PostMethod("http://%s:%s/"+aRota);
httpPost.addParameter("nome", "valor");
httpclient.executeMethod(httpPost);
return httpPost.getResponseBodyAsString();
}