README.md

Sample Java no-frameworks-other-than-servlets microservice.

Run it with

./gradlew build
java -cp build/libs/yourproject-all.jar com.thoughtworks.eg.AnyMicroService 8080

AnyMicroService.java

package com.thoughtworks.eg;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.eclipse.jetty.servlet.ServletHolder;

import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;

public class AnyMicroService extends HttpServlet {

	private static Server server;

	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		if (request.getRequestURI().startsWith("/hello")) {
			response.setStatus(200);
			response.setContentType("application/json");
			JsonObject json = new JsonObject();
			json.add("hello", new JsonPrimitive("world!"));
			response.getWriter().write(json.toString());
			return;
		}
		response.setStatus(404);
	}

	public static void main(String[] args) throws Exception {
		server = new Server(Integer.parseInt(args[0]));
		ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
		context.setContextPath("/");
		context.addServlet(new ServletHolder(new AnyMicroService()),"/*");
		server.setHandler(context);
		server.start();
	}

	public static void stop() throws Exception {
		server.stop();
		server.join();
	}
}

AnyMicroServiceTest.java

package com.thoughtworks.eg;

import static java.util.stream.Collectors.joining;
import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.CoreMatchers.startsWith;
import static org.junit.Assert.assertThat;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class AnyMicroServiceTest {

	@Before
	public void setUp() throws Exception {
		AnyMicroService.main(new String[] {"9292"});
	}

	@After
	public void tearDown() throws Exception {
		AnyMicroService.stop();
	}

	@Test
	public void hello() throws Exception {
		URL url = new URL("http://127.0.0.1:9292/hello");
		HttpURLConnection connection = (HttpURLConnection) url.openConnection();
		String result = new BufferedReader(new InputStreamReader(connection.getInputStream()))
	    		  .lines().collect(joining("\n"));

		assertThat(connection.getResponseCode(), is(200));
		assertThat(connection.getContentType(), startsWith("application/json"));
		assertThat(result, is("{\"hello\":\"world!\"}"));
	}

	@Test(expected=FileNotFoundException.class)
	public void notFound() throws Exception {
		URL url = new URL("http://127.0.0.1:9292/something-else");
		HttpURLConnection connection = (HttpURLConnection) url.openConnection();
		connection.getInputStream();
	}
}

build.gradle

apply plugin: 'java'
apply plugin: 'war'

sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    compile "com.google.code.gson:gson:2.3.1"
    compile 'org.eclipse.jetty:jetty-server:9.4.3.v20170317'
    compile 'org.eclipse.jetty:jetty-webapp:9.4.3.v20170317'
    providedCompile 'javax.servlet:servlet-api:2.5'
    testCompile "junit:junit:4.12"
}

task fatJar(type: Jar) {
    baseName = project.name + '-all'
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
    with jar
}

artifacts {
    archives fatJar
}