How do you create a REST client for Java? [closed]

Answer 1

I'd like to point out 2 more options:

• Restfulie, based on the VRaptor web framework, has both server and client side implementations with very good Hypermedia support.
• RESTEasy has a JAX-RS proxy based client implementation.

Answer 2

Since no one mentioned, here is another one: Feign, which is used by Spring Cloud.

Answer 3

You can use the standard Java SE APIs:

private void updateCustomer(Customer customer) { 
    try { 
        URL url = new URL("http://www.example.com/customers"); 
        HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 
        connection.setDoOutput(true); 
        connection.setInstanceFollowRedirects(false); 
        connection.setRequestMethod("PUT"); 
        connection.setRequestProperty("Content-Type", "application/xml"); 

        OutputStream os = connection.getOutputStream(); 
        jaxbContext.createMarshaller().marshal(customer, os); 
        os.flush(); 

        connection.getResponseCode(); 
        connection.disconnect(); 
    } catch(Exception e) { 
        throw new RuntimeException(e); 
    } 
} 

Or you can use the REST client APIs provided by JAX-RS implementations such as Jersey. These APIs are easier to use, but require additional jars on your class path.

WebResource resource = client.resource("http://www.example.com/customers"); 
ClientResponse response = resource.type("application/xml");).put(ClientResponse.class, "<customer>...</customer."); 
System.out.println(response); 

For more information see:

• http://bdoughan.blogspot.com/2010/08/creating-restful-web-service-part-55.html

Answer 4

I use Apache HTTPClient to handle all the HTTP side of things.

I write XML SAX parsers for the XML content that parses the XML into your object model. I believe that Axis2 also exposes XML -> Model methods (Axis 1 hid this part, annoyingly). XML generators are trivially simple.

It doesn't take long to code, and is quite efficient, in my opinion.

Answer 5

As I mentioned in this thread I tend to use Jersey which implements JAX-RS and comes with a nice REST client. The nice thing is if you implement your RESTful resources using JAX-RS then the Jersey client can reuse the entity providers such as for JAXB/XML/JSON/Atom and so forth - so you can reuse the same objects on the server side as you use on the client side unit test.

For example here is a unit test case from the Apache Camel project which looks up XML payloads from a RESTful resource (using the JAXB object Endpoints). The resource(uri) method is defined in this base class which just uses the Jersey client API.

e.g.

    clientConfig = new DefaultClientConfig();
    client = Client.create(clientConfig);

    resource = client.resource("http://localhost:8080");
    // lets get the XML as a String
    String text = resource("foo").accept("application/xml").get(String.class);        

BTW I hope that future version of JAX-RS add a nice client side API along the lines of the one in Jersey

Answer 6

I am currently using https://github.com/kevinsawicki/http-request I like their simplicity and the way examples are shown, but mostly I was sold when I read:

What are the dependencies?

None. The goal of this library is to be a single class class with some inner static classes. The test project does require Jetty in order to test requests against an actual HTTP server implementation.

which sorted out some problems on a java 1.6 project. As for decoding json into objects gson is just invincible :)