I have my endpoints like so:
#Path("/users")
public class Users {
private final SomeDependency dependency
public Users(SomeDependency dependency) {
this.dependency = dependency;
}
#GET
#Path("/{id}")
public Response Get(#PathParam("id") int id) {
User user = this.dependency.get(id);
return Response.ok(user).build();
}
}
Now how do I actually run a server with this endpoint?
I am confused about web servers/applications/servlets, using jersey jetty glassfish or whatever. Also web.xml files? what? ResourceConfigs only accept classes, not their instances. Everything seems to be such a mess.
How can I just do something similar to this?
public static void main(String[] args) throws Exception {
SomeDependency dependency = new SomeDependency();
Users usersEndpoint = new Users(dependency);
Server server = new Server();
server.registerEndpoint(usersEndpoint);
server.start();
}
Server
As far as the server goes, you have two types you have to consider: installed or embedded.
Installed
An installed server is one that is installed on your machine. For example, if you download Tomcat 10 and then follow the installation instruction, the server will get installed on your machine at whatever location you choose. In this situation, when you have an app (a war file) you are ready to deploy, you will copy it to your Tomcat server (to a specific location) and on server startup, Tomcat will see the application and then run it. The applications running in this type of environment will require a web.xml as they are deployed in a war file.
Embedded
An embedded server is one that is packaged into your jar application and is started in a main method just like any other Java SE application. Most installed servers also come with an embedded version. All you need to do is add the server dependencies into your application and then write the server configuration and startup (and shutdown) code. Applications running in this environment will not require a web.xml as they are deployed as a jar file.
Which one to use?
With the advancement and popularity of cloud services and microservices, many applications are moving towards embedded servers. The reason is that they are easy to deploy, are scalable, relatively lightweight, and applications become more self contained. There are many other pros that come with using embedded servers, but there are also some cons. Do your research before you make your final decision about which one you should use.
Example
If you want to quickly get started without having to worry about setting up the project, knowing what dependencies you need to add, adding the startup code, an easy way to get up and running is to use a Maven Archetype. If you go to the Jersey Docs, they get you started with an embedded Grizzly server running a Jersey application. What you need to do is run the following command from the command line (assuming you have Maven installed in your machine)
mvn archetype:generate -DarchetypeArtifactId=jersey-quickstart-grizzly2 \
-DarchetypeGroupId=org.glassfish.jersey.archetypes -DinteractiveMode=false \
-DgroupId=com.example -DartifactId=simple-service -Dpackage=com.example \
-DarchetypeVersion=2.33
If you read the docs I linked to, it will give an explanation of all that comes with the initial application. The main class will look like the following (with comments and imports omitted)
public class Main {
public static final String BASE_URI = "http://localhost:8080/myapp/";
public static HttpServer startServer() {
final ResourceConfig rc = new ResourceConfig().packages("org.example");
return GrizzlyHttpServerFactory.createHttpServer(URI.create(BASE_URI), rc);
}
public static void main(String[] args) throws IOException {
final HttpServer server = startServer();
System.out.println(String.format("Jersey app started with WADL available at "
+ "%sapplication.wadl\nHit enter to stop it...", BASE_URI));
System.in.read();
server.stop();
}
}
In this code, they use the packages() method of the ResourceConfig class that specifies a package for Jersey to scan for #Path and #Provider classes to register. In your case, if you don't need that, you can remove the method call. If you want to register your Users instance, all you do is call register(users) on the ResourceConfig.
See Also
What exactly is the ResourceConfig class in Jersey 2 - this link will help you get started with the ResourceConfig class and show you how you can register you resource classes or instances.
Other Frameworks
There are other frameworks out there that you may also want to consider
Dropwizard - Dropwizard is an opinionated framework built on top of Jersey. It uses an embedded Jetty as its server and comes with many other features to make developing your applications easier. They have pretty good, easy to follow documentation. There is a good "getting started" guide if you want to give them a try.
Spring Boot - Spring Boot is a bootstrapping framework that makes getting up and running with applications much easier. There are auto configurations made for you but give you options to change them. You can use Spring MVC or Jersey as the REST framework when you work with Spring Boot. There is also an Initializer, which is similar to the Maven Archetypes, but is interactive and allows you to add what you want to your applications.
So I just accepted the fact that java is an utter mess and pulled these dependencies in:
<dependency>
<groupId>org.apache.cxf</groupId>
<artifactId>cxf-rt-frontend-jaxrs</artifactId>
<version>3.4.2</version>
</dependency>
<dependency>
<groupId>javax.annotation</groupId>
<artifactId>javax.annotation-api</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.apache.cxf</groupId>
<artifactId>cxf-rt-transports-http-jetty</artifactId>
<version>3.4.2</version>
</dependency>
So i can launch everything like so:
public static void main(String[] args) throws Exception {
SomeDependency dependency = new SomeDependency();
Users usersEndpoint = new Users(dependency);
JAXRSServerFactoryBean serverFactory = new JAXRSServerFactoryBean();
serverFactory.setResourceClasses(usersEndpoint.getClass());
serverFactory.setResourceProvider(usersEndpoint.getClass(), new SingletonResourceProvider(usersEndpoint));
serverFactory.setAddress("http://localhost:8080/");
serverFactory.create().start();
}
I have more endpoints, of course, so I put everything in a for loop.
As to why I'm answering from a guest account, the account I used to ask this question was created using a disposable email address, and I can no longer access it.
Hope this helps anyone in the future!
Related
I have been trying to figure out an issue with spring boot and as i am new to spring I thought of getting some help here.
I have a spring boot based java application which runs as a daemon and makes some GET request to a remote server. (Acts only as a client).
But my spring boot application internally starts an embedded tomcat container.
My understanding is that if the java app acts as a server, it would need tomcat. But my application being only a consumer of remote machine's GET APIs, why would it need an embedded tomcat ?
In my pom file I have specified spring-boot-starter-web,
on assumption that it is needed for even making GET calls.
But after doing some research on disabling embedded tomcat, I found a solution.
To make following changes,
#SpringBootApplication(exclude = {EmbeddedServletContainerAutoConfiguration.class,
WebMvcAutoConfiguration.class})
&
in application.yml
spring:
main:
web-environment: false
With the application.yml changes, my jar is not even getting started, aborts directly, without even logging anything in logback logs.
Now, if i remove the application.yml change, my jar starts (only with first change in #SpringBootApplication anno.) but goes into some exception.
[main] o.s.boot.SpringApplication : Application startup failed
org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is org.springframework.context.ApplicationContextException: Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean.
My Doubts here are,
1) Is tomcat, be it standalone or embedded, really needed for a application which just makes GET API calls to remote machine ?
2) How do i overcome this exception and safely remove the embedded tomcat and still perform the GET API calls ?
You seem to be on completely the wrong track here, starting from a web application template and then trying to turn off the web application aspect.
Far better to start from a regular commandline client template and go from there, as detailed in the relevant Spring Guide.
Basically the application reduces to
#SpringBootApplication
public class Application {
private static final Logger log = LoggerFactory.getLogger(Application.class);
public static void main(String args[]) {
SpringApplication.run(Application.class);
}
#Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
return builder.build();
}
#Bean
public CommandLineRunner run(RestTemplate restTemplate) throws Exception {
return args -> {
Quote quote = restTemplate.getForObject(
"http://gturnquist-quoters.cfapps.io/api/random", Quote.class);
log.info(quote.toString());
};
}
}
And the pom to
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
</dependencies>
I had this problem. All I wanted was to have a Client making REST requests. Unfortunately I had a dependency which was embedding Jetty, and Jetty was always started.
In order to disable Jetty all I needed to do was to add in applications.properties the following entry:
spring.main.web-application-type=none
That fixed it.
Here is the most simple solution for me, make spring boot application just a restful api consumer.
Replace the dependence
implementation("org.springframework.boot:spring-boot-starter-web")
with
implementation("org.springframework.boot:spring-boot-starter-json")
RestTemplate and jackson are available in the project without embedded tomcat.
Answering your questions:
1) embedded by defaut - not needed for clients HTTP requests;
2) You can use CommandLineRunner for spring boot applications without any web:
#SpringBootApplication
public class SpringBootConsoleApplication implements CommandLineRunner {
public static void main(String[] args) {
SpringApplication.run(SpringBootConsoleApplication.class, args);
}
#Override
public void run(String... args) {
// TODO: start you thread here to execute client HTTP REST requests (or any other job you need)
}
}
This will disable web completelly - no issues with manual miss-configuration.
Here is some docs:
http://www.baeldung.com/spring-boot-console-app
You also need replase spring-boot-starter-web dependency with spring-boot-starter:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
From your question, i assume you want your application to keep running in background and it makes some get calls in it's life cycle. If that's the case, then
answering your first question, yes, you need an embedded tomcat or
jetty or need to deploy your application to an external application
server.
Second, to get rid of the exception your facing, don't exclude
EmbeddedServletContainerAutoConfiguration and
WebMvcAutoConfiguration class as it's needed for default embedded
tomcat auto configuration.
I'm maintaining a Java Enterprise Application that exposes a few webservices and interacts with a few JMS queues and a database.
I've got most of the code unit tested and I thought all was good until in a refactoring I moved a class in another package and that changed a namespace in my webservice without me noticing and breaking all clients.
An Integration Test would have caught that, so I'm trying to write one.
The application is deployed on JBoss EAP 6.4, how can I make a webservice call in my mvn verify step?
What about JMS Queues? They are configured on the Application Server.
Is the application supposed to be already deployed?
Am I supposed to deploy the application with maven to a JBoss installation before the verify step or start an embedded webserver?
Most of the docs around are confusing to me and often I see suggestion to mock stuff, which is not integration testing (and I already do in Unit tests).
Someone told me "just use Jenkins" and I read the docs, installed it and still don't understand how that is supposed to help me write integration tests since all it does is run mvn verify anyway.
This topic and is too broad, there might be many different correct answers for this question and will depend a lot on the technologies you're using, so I'll focus first in this part only:
that changed a namespace in my webservice without me noticing and
breaking all clients
You can create unit tests for endpoints too, I do that all the time with spring-boot. For example, the code below starts the application, runs the testEndpoint() test and shuts down the application right after.
#RunWith(SpringJUnit4ClassRunner.class)
#SpringApplicationConfiguration(classes = {MyApplication.class})
#WebAppConfiguration
#IntegrationTest("server.port:0")
public class MyControllerTest {
#Value("${local.server.port}")
private int port;
#Test
public void testEndpoint() {
String endpointUrl = "http://localhost:" + port;
// make a HTTP request here to test the endpoint
}
}
I believe this can be done with any spring-mvc application, but the code would be a bit different and not as easy as with spring-boot.
Although this would usually catch most bugs in endpoints, it doesn't eliminate the need of integration tests against a deployed project.
So focusing on the bigger picture now, if you want to create end-to-end tests, including WebServices, JMS queues and databases, I suggest creating a separate project with tests only, probably using Cucumber or something similar. This project should be triggered in Jenkins (or any other CI tool) whenever needed (e.g. before a deployment, every hour, every commit and/or every night) and it will require that all applications are already deployed.
Alternatively, you could have Jenkins deploy an application and run integration tests only against this one application. In this case the tests will depend on all other applications to be already deployed.
I spent quite a few days now trying to figure out how to add a website in OSGi.
I hava Restlet web service running with Jetty extension to use Jetty as a connector. This feature provides different resources under multiple URLs.
But I would also like to have a small website running on the system that can be accessed by the user. I wanted to use some HTML,Javascript,CSS and provide the current data status with some graphs and pictures.
I assume since Jetty is running in the background I would be able to deploy this website on Jetty and maybe call the server resources provided by Restlet in Javascript.
Apparently nothing worked except the restlet services.
My question would be is it possible to add a WAB bundle and expect it to work(Since Jetty is running in background)? Or is there any better way to add a website in OSGi?
Or
The only option I have now is, since it is possible to return an HTML form as a representation, add all my javascript code inside the HTML form and send it as a response to GET request(Which I believe is a mess).
Everything will run in Raspberry pi so I can only have a very small footprint. I am using Equinox, Restlet 2.3.0 and Jetty 9.2.6.
I would really appreciate if someone knows a link where i could get info on getting at least a sample page running in OSGi. I have tried many with no luck.
I recommend you to have a look at how it is done in Apache Karaf (https://github.com/apache/karaf). More on Apache Karaf and WebContainers here: http://karaf.apache.org/manual/latest/users-guide/webcontainer.html
In fact, Jetty is internally used by Restlet under the hood through its connector feature. This way, it's not convenient (and not the correct approach) to register dynamically applications.
That said, Restlet is really flexible and dynamic. This means that you can dynamically handle bundles that contain Restlet applications in a similar way than WAB bundles, i.e. attach them to virtual hosts of a component.
Here is the way to implement this:
Create a bundle that makes available the Restlet component into the OSGi container. You should leverage the FrameworkListener listener to be able that all connectors, converters, and so on... are registered into the Restlet engine:
private Component component;
public void start(BundleContext bundleContext) throws Exception {
bundleContext.addFrameworkListener(new FrameworkListener() {
component = new Component();
(...)
component.start();
});
}
public void stop(BundleContext bundleContext) throws Exception {
component.stop();
}
When the component is started, you can look for bundles that are present in the container and contained Restlet applications. For each bundle of this kind, you can register a dedicated OSGi service that make available the internal Restlet application you want to register against the component.
ServiceReference[] restletAppRefs = bundleContext.getServiceReferences(
"restletApplication",
null);
if (restletAppsRefs != null) {
for (ServiceReference restletAppRef : restletAppsRefs) {
RestletApplicationService descriptor
= (RestletApplicationService) bundleContext
.getService(serviceReference);
String path = descriptor.getPath();
Application restletApplication = descriptor.getApplication();
// Register the application against the component
(...)
}
}
Registering applications against the component is
try {
VirtualHost virtualHost = getExistingVirtualHost(
component, hostDomain, hostPort);
if (virtualHost == null) {
virtualHost = new VirtualHost();
virtualHost.setHostDomain(hostDomain);
virtualHost.setHostPort(hostPort);
component.getHosts().add(virtualHost);
}
Context context = component.getContext().createChildContext();
virtualHost.setContext(context);
virtualHost.attachDefault(application);
component.updateHosts();
application.start();
} catch(Exception ex) {
(...)
}
You also need to take into account the dynamics of OSGi. I mean bundles can come and go after the start of the OSGi container itself. You can leverage
bundleContext.addServiceListener(new ServiceListener() {
public void serviceChanged(ServiceEvent event) {
if (isServiceClass(event, RestletApplicationService)) {
int type = event.getType();
if (type == ServiceEvent.REGISTERED) {
// Register the Restlet application against the component
} else if (type == ServiceEvent.UNREGISTERING) {
// Unregister the Restlet application
}
}
}
});
Hope it helps you,
Thierry
There are many options available to you - OSGi doesn't really impose many restrictions on what you can do. If you want to use OSGi's capabilities then here's a couple of ideas:
One option would be to deploy a WAB. You'll need to ensure that your framework has the necessary OSGi Services running though. Just because some bundle is using Jetty internally it doesn't follow that the necessary OSGi services are running.
The bundle org.apache.felix.http.jetty does provide the necessary services to deploy a WAB. Version 2.2.2 is 1.3MB on disk, and embeds its own copy of Jetty. Other implementations are available (e.g. Pax-Web, as used in Karaf - which also embeds Jetty)
Another option would be to use the OSGi Http service directly (again you'd need to include a bundle which implements this service (like the Felix one mentioned). A call to org.osgi.service.http.HttpService.registerResources() will serve up static content from within your bundle.
If the this additional footprint is a real concern then you might want to look at how you can get Restlet to use the OSGi http service, rather than providing it's own via embedded Jetty.
Yet another option would be to take a Jetty centric view of things. Restlet's embedded Jetty is probably not configured to serve arbitrary content from disk. You could look at either re-configuring the embedded Jetty to do this, or consider deploying Restlet to a 'standard' Jetty install. Personally, I'd try the latter.
I know you can build a WAR file to deploy to an application server, but what kind of server is created when you run the main Application class?
/**
* Main method, used to run the application.
*/
public static void main(String[] args) throws UnknownHostException {
SpringApplication app = new SpringApplication(Application.class);
SimpleCommandLinePropertySource source = new SimpleCommandLinePropertySource(args);
addDefaultProfile(app, source);
Environment env = app.run(args).getEnvironment();
log.info("Access URLs:\n-----------------------------------------------------\n\t" +
"Local: \t\thttp://127.0.0.1:{}\n\t" +
"External: \thttp://{}:{}\n-----------------------------------------------",
env.getProperty("server.port"),
InetAddress.getLocalHost().getHostAddress(),
env.getProperty("server.port"));
}
By default Spring Boot uses Tomcat. You can configure it to use Jetty or Undertow as embedded container. You can check your pom.xml and see if there are any references to them. If not, you can assume, it is Tomcat
After version of 3.7.0 JHipster migrated to Undertow. The release note says:
Migration to Undertow is our biggest change - see #4054. This brings some very good performance enhancements in start up time and memory usage: this is good for everyone, but people doing microservices will benefit from it even more. With this change, JHipster uses nearly as much JBoss code (Undertow, Hibernate, Bean Validation, MapStruct) as Spring code!
For more information visit here
OK, I am developing a program which will be deployed to lots of machines (Windows, Linux, AIX, z/Linux, openVMS, etc.). I want that application to contain a SOAP web service, but I don't want to bundle tomcat or run a separate service for the services (I want them in the same process as the rest of the application).
Basically what I'm looking for is something where I can define a class (say WebServices). I'm OK with writing WSDL or any other kind of service description as well. The I want something like this:
SOAPServer server = makeMeASoapServer();
//do config on the server
server.add(new WebService(...));
server.listen(port);
Obviously the names and parameters will be different.
I've been looking at Axis, and it seems like it provides this, but I don't know what classes I need to use. Am I crazy in wanting this kind of behavior? I can't believe more people aren't looking for this, I do this all the time with embedded web services within .NET clients.
Seems jdk 6.0 already comes with a jax-ws implementation, and a little server you can embed.
I havn't figured out all the pieces but here's a start:
mkdir -p helloservice/endpoint/
helloservice/endpoint/Hello.java :
package helloservice.endpoint;
import javax.jws.WebService;
#WebService()
public class Hello {
private String message = new String("Hello, ");
public void Hello() {}
public String sayHello(String name) {
return message + name + ".";
}
}
helloservice/endpoint/Server.java:
package helloservice.endpoint;
import javax.xml.ws.Endpoint;
public class Server {
protected Server() throws Exception {
System.out.println("Starting Server");
Object implementor = new Hello();
String address = "http://localhost:9000/SoapContext/SoapPort";
Endpoint.publish(address, implementor);
}
public static void main(String args[]) throws Exception {
new Server();
System.out.println("Server ready...");
Thread.sleep(5 * 60 * 1000);
System.out.println("Server exiting");
System.exit(0);
}
}
Build the thing:
mkdir build
javac -d build helloservice/endpoint/*java
$JAVA_HOME/wsgen -d build -s build -classpath . helloservice.endpoint.Hello
Run the thing:
java -cp build helloservice.endpoint.Server
Somethings running on http://localhost:9000/SoapContext/SoapPort now.
You can get the wsdl on http://localhost:9000/SoapContext/SoapPort?WSDL
Havn't gotten around to making a client yet..
In addition to nos's great answer, I found a class in Apache axis called SimpleHTTPServer which I'm pretty sure does the same thing but only requires Java 1.5 for those of you stuck with 1.5
I'm not going to explore it since I'm going to use the other solution, so I haven't actually verified it does what I think it does, but I'm pretty sure it does.
Most(/all?) Java SOAP server implementations provide a Servlet (the javax.xml.ws.Endpoint approach in another answer does look a bit simpler though...). Some SOAP implementations you could consider are: Apache CXF: cxf.apache.org, Apache Axis2: ws.apache.org/axis2/ or Spring Web Servies: static.springsource.org/spring-ws/site/ .
The most popular embedded Java web server seems to be Jetty, you can configure it either programatically (using plain Java or Spring beans) or using a custom XML format.
To address the main question directly, another approach would be to go with Jetty's embedded server. See this link for details. The links from the aforelinked page help you understand both the simple web server (i.e., one that serves up static pages; though I am fully aware "simple" is a horribly vague term wrt web servers) and the web server that helps you deploy web services.