RMI client with another port - client-server

I've really searched hours and hours but I didn't find any solutions. I want that my client on a VM (Windows server 2008) get in communication with my host (main system: windows 7).
public class TestClient
{
public static void main(String[] args) throws RemoteException, NotBoundException
{
Registry registry = LocateRegistry.getRegistry("13.211.124.80",TestRemote.RMI_PORT);
TestRemote remote = (TestRemote) registry.lookup(TestRemote.RMI_ID);
System.out.println(remote.isLoginValid("tst"));
System.out.println(remote.isLoginValid("test"));
System.out.println(TestRemote.RMI_PORT);
}
}
IP from host: 13.211.124.80
RMI Server class
public class RMIServer
{
public static void main (String[] args) throws RemoteException, AlreadyBoundException
{
RemoteImpl impl = new RemoteImpl();
Registry registry=LocateRegistry.createRegistry(TestRemote.RMI_PORT);
registry.bind(TestRemote.RMI_ID, impl);
System.out.println("server is started");
}
}
Impl Class:
public class RemoteImpl extends UnicastRemoteObject implements TestRemote
{
private static final long serialVersionUID = 1L;
protected RemoteImpl() throws RemoteException
{
super();
// TODO Auto-generated constructor stub
}
public boolean isLoginValid(String username) throws RemoteException
{
if (username.equals("test"))
{
return true;
}
return false;
}
}
Interface class:
public interface TestRemote extends Remote
{
public boolean isLoginValid(String username) throws RemoteException;
public static final String RMI_ID = "TestRMI";
public static final int RMI_PORT = 888;
}
Error:
Exception in thread "main" java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.lang.ClassNotFoundException: com.interf.test.TestRemote (no security manager: RMI class loader disabled)

The exception is perfectly clear. Whatever component threw that exception does not have that class on its CLASSPATH. It could have been the Registry or the client, depending on the stack trace, which you didn't post completely.

Related

Spring Boot and Java Fx

To start my application, I'm avoiding the "implements CommandLineRunner" process to do the setup but I am facing a problem in this line
fxmlLoader.setControllerFactory(springContext::getBean);
where fxmlLoader is an instance of FxmlLoader and springContext ia an instance of ConfigurableApplicationContext. I am facing this error,
"The method setControllerFactory(Callback<Class<?>,Object>) in the
type FXMLLoader is not applicable for the arguments
(springContext::getBean)".
Can anyone help me with the exact syntax? My imported package reports an error as
"The type org.springframework.beans.factory.annotation.Autowire
cannot be resolved. It is indirectly referenced from required .class
files" .
ok, ive understood that this would require a little code, but ive found already built project with a solution similar to what ive proposed - heres example https://github.com/ruslanys/sample-spring-boot-javafx
you just to tie javafx to spring with context.getAutowireCapableBeanFactory().autowireBean(this);
in AbstractJavaFxApplicationSupport.java file
code will look like this
public abstract class AbstractJavaFxApplicationSupport extends Application {
private static String[] savedArgs;
protected ConfigurableApplicationContext context;
#Override
public void init() throws Exception {
context = SpringApplication.run(getClass(), savedArgs);
context.getAutowireCapableBeanFactory().autowireBean(this);
}
#Override
public void stop() throws Exception {
super.stop();
context.close();
}
protected static void launchApp(Class<? extends AbstractJavaFxApplicationSupport> appClass, String[] args) {
AbstractJavaFxApplicationSupport.savedArgs = args;
Application.launch(appClass, args);
}
}
and tie all you view like bean
#Configuration
public class ControllersConfiguration {
#Bean(name = "mainView")
public ViewHolder getMainView() throws IOException {
return loadView("fxml/main.fxml");
}
#Bean
public MainController getMainController() throws IOException {
return (MainController) getMainView().getController();
}
protected ViewHolder loadView(String url) throws IOException {
InputStream fxmlStream = null;
try {
fxmlStream = getClass().getClassLoader().getResourceAsStream(url);
FXMLLoader loader = new FXMLLoader();
loader.load(fxmlStream);
return new ViewHolder(loader.getRoot(), loader.getController());
} finally {
if (fxmlStream != null) {
fxmlStream.close();
}
}
}
public class ViewHolder {
private Parent view;
private Object controller;
public ViewHolder(Parent view, Object controller) {
this.view = view;
this.controller = controller;
}
public Parent getView() {
return view;
}
public void setView(Parent view) {
this.view = view;
}
public Object getController() {
return controller;
}
public void setController(Object controller) {
this.controller = controller;
}
}
}
then in controller you may enjoy spring magic and javafx magic together
public class MainController {
#Autowired private ContactService contactService;
#FXML private TableView<Contact> table;
#FXML private TextField txtName;
#FXML private TextField txtPhone;
#FXML private TextField txtEmail;}
and just start your app like this
#SpringBootApplication
public class Application extends AbstractJavaFxApplicationSupport {
#Value("${ui.title:JavaFX приложение}")//
private String windowTitle;
#Qualifier("mainView")
#Autowired
private ControllersConfiguration.ViewHolder view;
#Override
public void start(Stage stage) throws Exception {
stage.setTitle(windowTitle);
stage.setScene(new Scene(view.getView()));
stage.setResizable(true);
stage.centerOnScreen();
stage.show();
}
public static void main(String[] args) {
launchApp(Application.class, args);
}}

Session management in a Neo4J Flink sink

I am developing a data analytics app with Apache Flink and Neo4J (Community Edition).
In this application, the Flink sink must save/update relations in Neo4J.
Which is the best way for Neo4J session management, and why?
First implementation:
public class MySink extends RichSinkFunction<Link> {
private DbConfiguration dbconfig;
private Driver driver;
#Override
public void open(Configuration parameters) throws Exception {
this.driver = Neo4JManager.open(this.dbconfig);
}
#Override
public void close() throws Exception {
this.driver.close();
}
#Override
public void invoke(Link link) throws Exception {
Session session = this.driver.session();
Neo4JManager.saveLink(session, link);
session.close();
}
}
Second implementation:
public class MySink extends RichSinkFunction<Link> {
private DbConfiguration dbconfig;
private Driver driver;
private Session session;
#Override
public void open(Configuration parameters) throws Exception {
this.driver = Neo4JManager.open(this.dbconfig);
this.session = driver.session();
}
#Override
public void close() throws Exception {
this.session.close();
this.driver.close();
}
#Override
public void invoke(Link link) throws Exception {
Neo4JManager.saveLink(this.session, link);
}
}
In both implementations, the following functions have been used:
public class Neo4JManager {
public static Driver open(DbConfiguration dbconf) {
AuthToken auth = AuthTokens.basic(dbconf.getUsername(), dbconf.getPassword());
Config config = Config.build().withEncryptionLevel(Config.EncryptionLevel.NONE ).toConfig();
return GraphDatabase.driver(dbconf.getHostname(), auth, config);
}
public static void saveLink(Session session, Link link) {
Value params = parameters("x", link.x, "y", link.y);
session.run('CREATE (Person {id:{x}}-[FOLLOWS]->(Person {id:{y}}))'
}
}
Thank you.

Error: java.lang.NullPointerException in Client with WebService. How fixed it?

I'm doing a example about jax-ws-spring-integration. My project have following structure.
In Client
Here file UserClient.java
public class UserClient {
static UserService service;
public static void main(String[] args) {
// TODO Auto-generated method stub
// System.out.println("From webservice"
// + service.sayHello("Nguyen van a"));
service = new UserService();
User user = service.getUser("hoaipham");
System.out.println("Hello" + user.getUserName());
System.out.println("Email" + user.getAge());
}
}
Here file UserService.java
#WebService
#Component
public class UserService {
#Autowired
private UserBo userBo;
#WebMethod(operationName = "getUser")
public User getUser(String username){
return userBo.loadUser(username);
}
#WebMethod(operationName = "say")
public String sayHello(String name){
return "Hanoi Java say hello to" + name;
}
}
When i run "main" in Client then occur following error:
Exception in thread "main" java.lang.NullPointerException at
edu.java.spring.ws.UserService.getUser(UserService.java:19) at
Client.UserClient.main(UserClient.java:14)
Hm, it looks like Spring not working in the Client (in a different jvm).
Try to create a instance of AnnotationConfigApplicationContext and add your class to the Context (or let the instance scan the package).
EDIT:
Try
public class UserClient {
static UserService service;
public static void main(String[] args) {
// TODO Auto-generated method stub
// System.out.println("From webservice"
// + service.sayHello("Nguyen van a"));
service = new AnnotationConfigApplicationContext(UserService.class)
.getBean(UserService.class);
User user = service.getUser("hoaipham");
System.out.println("Hello" + user.getUserName());
System.out.println("Email" + user.getAge());
}
}

Exiting a SpringBoot app - how do I get a reference to SpringApplication?

I realize that to programmatically exit a SpringBoot 4 application I want to call the exit() method of SpringApplication, but how can I get a reference to it?
Of course I have access to it in my main() method, but I ask because if I'm in some class that is loading a resource and fails, I want to terminate the app, but from that class I can't figure out how to access SpringApplication.
Thanks...
A cleaner approach for this use case is to use events & listeners wherein you have to add your listener to SpringApplication class which will listens to an event like in your case a resource load failure and then subsequently act accordingly i.e. exit the application. You can get application context handle by implementing the ApplicationContextAware interface. Details on event & listener can be found here.
MyEvent class :-
public class MyEvent extends ContextRefreshedEvent {
private static final long serialVersionUID = 1L;
#Autowired
public MyEvent(ApplicationContext source) {
super(source);
}
}
MyEvent listener class :-
#Component
public class MyListener implements ApplicationListener<ContextRefreshedEvent> {
#Override
public void onApplicationEvent(ContextRefreshedEvent event) {
if(event instanceof MyEvent){
SpringApplication.exit(event.getApplicationContext(), new ExitCodeGenerator() {
#Override
public int getExitCode() {
return 2;
}
});
}
}
}
Resource loader class:-
#Component
public class MyResourceLoader implements ApplicationContextAware, CommandLineRunner {
private ApplicationContext ctx ;
#Autowired
private ApplicationEventPublisher publisher;
#Override
public void run(String... args) throws Exception {
//inside RUN for resource load failure
publisher.publishEvent(new MyEvent(ctx));
}
#Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
ctx = applicationContext;
}
}

Spring boot check external service status on boot

I want check some external http service before my Spring Boot is ready.
The url to the external web service are stored in a property file with a #ConfigurationProperties class.
How do this check i tried using a springApplication.addListner() with a ping method. But the property class have not then been initialized.
public class ApplicationStartListener implements ApplicationListener<ApplicationPreparedEvent> {
#Override
public void onApplicationEvent(ApplicationPreparedEvent event) {
String url = AppProp.getURL();
inet = InetAddress.getByName(url );
inet.isReachable(5000)
...
application.yml
tops:
http://service.com
#Component
#ConfigurationProperties("tops")
public class AppProp{
private static String url;
public static String getUrl() {
The easiest way to accomplish this is to implement the ApplicationRunner interface.
From the Spring Boot documentation [1]
If you need to run some specific code once the SpringApplication has started, you can implement the ApplicationRunner or CommandLineRunner interfaces. Both interfaces work in the same way and offer a single run method which will be called just before SpringApplication.run(…​) completes.
[1] https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-spring-application.html#boot-features-command-line-runner
Assuming you have url defined in application.properties:
#SpringBootApplication
public class MyApplication implements ApplicationRunner
{
#Inject
private AppConfig appConfig;
#Inject
private ConfigurableApplicationContext applicationContext;
public static void main(String[] args)
{
SpringApplication.run(MyApplication.class, args);
}
#Override
public void run(ApplicationArguments args) throws Exception
{
InetAddress inetAddress = InetAddress.getByName(appConfig.getUrl());
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Component
#ConfigurationProperties
public static class AppConfig
{
private String url;
public String getUrl()
{
return url;
}
public void setUrl(String url)
{
this.url = url;
}
}
}
If you need even more control than this, you can use SpringApplicationRunListener [2]
[2] http://docs.spring.io/spring-boot/docs/current/api/org/springframework/boot/SpringApplicationRunListener.html
#SpringBootApplication
public class MyApplication implements SpringApplicationRunListener
{
public MyApplication() { }
public MyApplication(SpringApplication springApplication, String[] args) { }
public static void main(String[] args)
{
SpringApplication.run(MyApplication.class, args);
}
#Override
public void started() { }
#Override
public void environmentPrepared(ConfigurableEnvironment environment)
{
// 1st opportunity
InetAddress inetAddress = InetAddress.getByName(environment.getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Override
public void contextPrepared(ConfigurableApplicationContext context)
{
// 2nd opportunity
InetAddress inetAddress = InetAddress.getByName(context.getEnvironment().getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Override
public void contextLoaded(ConfigurableApplicationContext context)
{
// 3rd opportunity
InetAddress inetAddress = InetAddress.getByName(context.getEnvironment().getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Override
public void finished(ConfigurableApplicationContext context, Throwable exception)
{
// 4th opportunity
InetAddress inetAddress = InetAddress.getByName(context.getEnvironment().getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Component
#ConfigurationProperties
public static class AppConfig {
private String url;
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
}
}
then create META-INF\spring.factories and add
org.springframework.boot.SpringApplicationRunListener=com.foobar.MyApplication

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