Liferay is easy: Creating Rest API in Liferay 7 (JAX-RS Web Services)

Today we will discuss how to create Rest Services in Liferay. By using JAX-RS we will create Rest Services that can be used by other applications. Here i am using Liferay 7.3.

So lets start this step by step :-

Step 1:- Create a simple Rest Portlet

Create a simple Liferay module Project and select Rest Template

After that provide Class Name(DemoRest) and package name (com.portal.rest)

And Click Finish.

You will see new project is created and Application is appended with class as well as package.

Now Class name become DemoRestApplication and package name become com.portal.rest.application.

DemoRestApplication.java

	package com.portal.rest.application;

	import java.util.Collections;
	import java.util.Set;

	import javax.ws.rs.GET;
	import javax.ws.rs.Path;
	import javax.ws.rs.PathParam;
	import javax.ws.rs.Produces;
	import javax.ws.rs.QueryParam;
	import javax.ws.rs.core.Application;

	import org.osgi.service.component.annotations.Component;
	import org.osgi.service.jaxrs.whiteboard.JaxrsWhiteboardConstants;

	/**
	* @author adit2
	*/
	@Component(
	property = {
	JaxrsWhiteboardConstants.JAX_RS_APPLICATION_BASE + "=/greetings",
	JaxrsWhiteboardConstants.JAX_RS_NAME + "=Greetings.Rest"
	},
	service = Application.class
	)
	public class DemoRestApplication extends Application {

	public Set<Object> getSingletons() {
	return Collections.<Object>singleton(this);
	}

	//http://localhost:8080/o/greetings/
	@GET
	@Produces("text/plain")
	public String working() {
	return "It works!";
	}

	//http://localhost:8080/o/greetings/morning
	@GET
	@Path("/morning")
	@Produces("text/plain")
	public String hello() {
	return "Good morning!";
	}

	//http://localhost:8080/o/greetings/morning/:name?drink=Cofee
	@GET
	@Path("/morning/{name}")
	@Produces("text/plain")
	public String morning(
	@PathParam("name") String name,
	@QueryParam("drink") String drink) {

	String greeting = "Good Morning " + name;
	if (drink != null) {
	greeting += ". Would you like some " + drink + "?";
	}
	return greeting;
	}
	}

view raw DemoRestApplication.java hosted with ❤ by GitHub

Explanation:-

1)In Line 21 we define base URL as /greetings

2) JAX_RS_NAME is Greetings.Rest

Step 2:- Register JAX-RS Web Service

Your JAX-RS web service requires authorization by default. To enable this, you must create an OAuth 2.0 application to provide a way to grant access to your service.

Go to Control panel->Security->OAuth 2 Administration