public final class WebSocketRegistryListener implements ApplicationListener<ApplicationEvent> {
#Override
public void onApplicationEvent(ApplicationEvent event) {
if(event instanceof SessionDisconnectEvent) {
SessionDisconnectEvent e = (SessionDisconnectEvent) event;
Map<String, Object> sessionAttributes = SimpMessageHeaderAccessor.getSessionAttributes(e.getMessage().getHeaders());
}
}
}
e.getMessage().getHeaders(); which doesn't exsit.How to write it is correct?
First of all, share, please, StackTrace on the matter.
There is no reason to have such a generic ApplicationListener<ApplicationEvent> if you are going to get deal just with SessionDisconnectEvent. You can use the last one as generic type of the ApplicationListener.
And bare in mind SessionDisconnectEvent extends AbstractSubProtocolEvent with getMessage() is available since Spring 4.1.1
Related
I had implement CQRS+ES application using axon and spring-boot. I use separate query model and command model application. I use rabbitmq to publish event from command mode. It works correct. But tracking Processor implementation is not work in my application.
This is my query model
#SpringBootApplication
public class SeatQueryPart1Application {
public static void main(String[] args) {
SpringApplication.run(SeatQueryPart1Application.class, args);
}
#Bean
public SpringAMQPMessageSource statisticsQueue(Serializer serializer) {
return new SpringAMQPMessageSource(new DefaultAMQPMessageConverter(serializer)) {
#RabbitListener(exclusive = false, bindings = #QueueBinding(value = #Queue, exchange = #Exchange(value = "ExchangeTypesTests.FanoutExchange", type = ExchangeTypes.FANOUT), key = "orderRoutingKey"))
#Override
public void onMessage(Message arg0, Channel arg1) throws Exception {
super.onMessage(arg0, arg1);
}
};
}
#Autowired
public void conf(EventHandlingConfiguration configuration) {
configuration.registerTrackingProcessor("statistics");
}
}
this is a event handler class
#ProcessingGroup("statistics")
#Component
public class EventLoggingHandler {
private SeatReservationRepository seatReservationRepo;
public EventLoggingHandler(final SeatReservationRepository e) {
this.seatReservationRepo = e;
}
#EventHandler
protected void on(SeatResurvationCreateEvent event) {
Timestamp timestamp = new Timestamp(System.currentTimeMillis());
Seat seat=new Seat(event.getId(), event.getSeatId(), event.getDate(),timestamp ,true);
seatReservationRepo.save(seat);
}
}
this is yml configuration
axon:
eventhandling:
processors:
statistics.source: statisticsQueue
How can i do it correct. (Can anyone suggest tutorial or code sample)
The SpringAMQPMessageSource is a SubscribableMessageSource. This means you cannot use a tracking event processor to process messages. It is only compatible with a Subscribable Event Processor.
Removing configuration.registerTrackingProcessor("statistics"); and leaving it to the default (subscribing) should do the trick.
I am writing a Spring Batch application using Spring Boot 1.5, following are my classes : -
CustomMultiResourceItemReader.java
#StepScoped
#Component
public class CustomMultiResourceItemReader
extends MultiResourceItemReader<MyDTO> {
public MultiResourceXmlItemReader(
#NonNull final MyResourceAwareItemReader itemReader,
#NonNull final ApplicationContext ctx)
throws IOException {
setResources(
ctx.getResources(
String.format(
"file:%s/*.xml", "~/data"))); // gives me a Resource[] array fine
setDelegate(itemReader);
}
#PreDestroy
void destroy() {
close();
}
}
MyResourceAwareItemReader.java
#RequiredArgsConstructor
#StepScope
#Component
#Slf4j
public class MyResourceAwareItemReader
implements ResourceAwareItemReaderItemStream<MyDTO> {
private static final String RESOURCE_NAME_KEY = "RESOURCE_NAME_KEY";
#NonNull private final Unmarshaller unmarshaller; // JaxB Unmarshaller
private Resource resource;
#Override
public void setResource(Resource resource) {
this.resource = resource; // **gets called only once**
}
#Override
public MyDTO read() throws Exception {
final MyDTO dto = (MyDTO) unmarshaller.unmarshal(resource.getFile()); // Standard JaxB unmarshalling.
return dto;
}
#Override
public void open(ExecutionContext executionContext) throws ItemStreamException {
if (executionContext.containsKey(RESOURCE_NAME_KEY)) {
} else if (resource != null) {
executionContext.put(RESOURCE_NAME_KEY, resource.getFilename());
}
}
#Override
public void update(ExecutionContext executionContext) throws ItemStreamException {
if (resource != null) executionContext.put(RESOURCE_NAME_KEY, resource.getFilename());
}
#Override
public void close() throws ItemStreamException {}
}
The problem is the setResource method in the delegate reader (MyResourceAwareItemReader.java) gets called only once at the beginning; while the read method gets called multiple times, as a result I read the same item multiple times, instead of reading the next item as expected.
I have also browsed the source code of MultiResouceItemReader in Spring Batch, it seems like, the read method of the delegate class is supposed to return null after each item is read, I can clearly see my code doesnt seem to do that.
I am bit lost how to make this work. Any help is much appreciated
Looking further into it, ItemReader documentation, clearly details that reader must return null at the end of the input data set. So basically I implemented my ItemReader with a boolean flag as follows: -
#RequiredArgsConstructor
#StepScope
#Component
#Slf4j
public class MyResourceAwareItemReader
implements ResourceAwareItemReaderItemStream<MyDTO> {
private static final String RESOURCE_NAME_KEY = "RESOURCE_NAME_KEY";
#NonNull private final Unmarshaller unmarshaller; // JaxB Unmarshaller
private Resource resource;
private boolean isResourceRead;
#Override
public void setResource(Resource resource) {
this.resource = resource;
isResourceRead = false;
}
#Override
public MyDTO read() throws Exception {
if(isResourceRead == true) return null;
final MyDTO dto = (MyDTO) unmarshaller.unmarshal(resource.getFile());
isResourceRead = true;
return dto;
}
#Override
public void open(ExecutionContext executionContext) throws ItemStreamException {
if (executionContext.containsKey(RESOURCE_NAME_KEY)) {
} else if (resource != null) {
executionContext.put(RESOURCE_NAME_KEY, resource.getFilename());
}
}
#Override
public void update(ExecutionContext executionContext) throws ItemStreamException {
if (resource != null) executionContext.put(RESOURCE_NAME_KEY, resource.getFilename());
}
#Override
public void close() throws ItemStreamException {}
}
MultiResourceItemReader does not returns null each time. If there are no more resources to read the it returns NULL otherwise it returns the next resources to the delegate that means – Your actual reader
I can see problem in your read() method . you are not moving to next file. As you are implementing you own MultiResourceItemReader It’s your responsibility to move to next resources item.
This is how it is implanted in MultiResourceItemReader . You will need your own similar implementation.
private T readNextItem() throws Exception {
T item = delegate.read();
while (item == null) {
currentResource++;
if (currentResource >= resources.length) {
return null;
}
delegate.close();
delegate.setResource(resources[currentResource]);
delegate.open(new ExecutionContext());
item = delegate.read();
}
return item;
}
You need to maintain index of resources array . Please check implementation of MultiResourceItemReader. You need to do exactly similar way
I am new to spring
I have this class :
public class Server extends TextWebSocketHandler implements WebSocketHandler {
WebSocketSession clientsession;
#Override
public void handleTextMessage(WebSocketSession session, TextMessage message) {
clientsession = session;
}
I need to detect a client disconnect on clientsession.
implement ApplicationListener but its not clear how I can register the listener?
do I need to do it in my web.xml ?
The WebSocketHandler afterConnectionClosed function is called after a websocket client disconnects. You simply need to override this in the manner that you override handleTextMessage.
#Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus){
// your code here
}
There may be substantial delay between the client disconnect and your server event detection. See details about real-time disconnection detection.
You will need to override configureClientOutboundChannel and configureClientInboundChannel of AbstractWebSocketMessageBrokerConfigurer, providing your interceptor
Another way is using ApplicationEvents.
Both methods are described here:
http://www.sergialmar.com/2014/03/detect-websocket-connects-and-disconnects-in-spring-4/
public class StompConnectEvent implements ApplicationListener<SessionConnectEvent> {
private final Log logger = LogFactory.getLog(StompConnectEvent.class);
public void onApplicationEvent(SessionConnectEvent event) {
StompHeaderAccessor sha = StompHeaderAccessor.wrap(event.getMessage());
String company = sha.getNativeHeader("company").get(0);
logger.debug("Connect event [sessionId: " + sha.getSessionId() +"; company: "+ company + " ]");
}
}
I hope that help. Let me know if I need to explain more.
You can use listeners to detect when session is connected or closed.
More information about listeners you can find by this link.
Example how to detect connected session:
#Component
public class SessionConnectedEventListener implements ApplicationListener<SessionConnectedEvent> {
private IWebSocketSessionService webSocketSessionService;
public SessionConnectedEventListener(IWebSocketSessionService webSocketSessionService) {
this.webSocketSessionService = webSocketSessionService;
}
#Override
public void onApplicationEvent(SessionConnectedEvent event) {
webSocketSessionService.saveSession(event);
}
}
Example how to detect when session is disconneted:
#Component
public class SessionDisconnectEventListener implements ApplicationListener<SessionDisconnectEvent> {
private IWebSocketSessionService webSocketSessionService;
public SessionDisconnectEventListener(IWebSocketSessionService webSocketSessionService) {
this.webSocketSessionService = webSocketSessionService;
}
#Override
public void onApplicationEvent(SessionDisconnectEvent event) {
webSocketSessionService.removeSession(event);
}
}
What you probably want to achieve is maintaining multiple sessions. Something like this:
public class Server extends TextWebSocketHandler implements WebSocketHandler {
private List<WebSocketSession> sessions = new ArrayList<>();
#Override
public void afterConnectionEstablished(WebSocketSession session) {
sessions.add(session);
}
#Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
sessions.remove(session);
}
#Override
public void handleTextMessage(WebSocketSession session, TextMessage message) {
// clientsession = session;
// Send individual or broadcast messages here ...
session.sendMessage(new TextMessage(textMessage + "!"));
}
}
I'm trying to add a Filter that creates an object that is then to be used inside a controller in a Spring Boot application.
The idea is to use the Filter as a "centralized" generator of this object - that is request-specific and useful only in a controller.
I've tried to use the HttpServletRequest request.getSession().setAttribute method: I can access my object in the controller, but then it will be (clearly) added to the session.
Are the Filters the right way to do so? If yes, where can I keep the temporary object generated by the filter to be used by the controllers?
Why Don't you use a Bean with the #Scope('request')
#Component
#Scope(value="request", proxyMode= ScopedProxyMode.TARGET_CLASS)
class UserInfo {
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
private String password;
}
and then you can Autowireed this bean in both filter and controller to do setting and getting of data.
lifecycle of this UserInfo bean is only exisits within the request so once the http request is done then it terminates the instance as well
you can use ServletRequest.setAttribute(String name, Object o);
for example
#RestController
#EnableAutoConfiguration
public class App {
#RequestMapping("/")
public String index(HttpServletRequest httpServletRequest) {
return (String) httpServletRequest.getAttribute(MyFilter.passKey);
}
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
#Component
public static class MyFilter implements Filter {
public static String passKey = "passKey";
private static String passValue = "hello world";
#Override
public void init(FilterConfig filterConfig) throws ServletException {
}
#Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
request.setAttribute(passKey, passValue);
chain.doFilter(request, response);
}
#Override
public void destroy() {
}
}
}
An addition to wcong's answer.
Since Spring 4.3 after setting the attribute by using request.setAttribute(passKey, passValue);, you can access the attribute in your controller by simply annotating it with #RequestAttribute.
ex.
#RequestMapping("/")
public String index(#RequestAttribute passKey) {
return (String) passKey;
}
I dont know actually what is the scenario but If you really want to create an object in a filter and then use it somewhere in the code then you may use ThreadLocal class to do so.
To get know how this work see the most voted answer from that question Purpose of ThreadLocal?
In general using ThreadLocal you will be able to create a class that can store objects available ONLY for the current thread.
Sometimes for optimization reasons the same thread can be used to serve subsequent request as well so it will be nice to clean the threadLocal value after the request is processed.
class MyObjectStorage {
static private ThreadLocal threadLocal = new ThreadLocal<MyObject>();
static ThreadLocal<MyObject> getThreadLocal() {
return threadLocal;
}
}
in the filter
MyObjectStorage.getThreadLocal().set(myObject);
and in the Controller
MyObjectStorage.getThreadLocal().get();
Instead of filter you can use also #ControllerAdvice and pass objects to specified Controllers by using model.
#ControllerAdvice(assignableTypes={MyController.class})
class AddMyObjectAdvice {
// if you need request parameters
private #Inject HttpServletRequest request;
#ModelAttribute
public void addAttributes(Model model) {
model.addAttribute("myObject", myObject);
}
}
#Controller
public class MyController{
#RequestMapping(value = "/anyMethod", method = RequestMethod.POST)
public String anyMethod(Model model) {
MyObjecte myObject = model.getAttribute("myObject");
return "result";
}
}
I want to create a custom of HttpMessageConverter using Rest, Json, Spring Boot 1.2.3 and Spring 4, However my custom HTTPMessageConverter its' never called.
I have preformed the following steps :
1: Created a class that extends AbstractHttpMessageConverter
#Component
public class ProductConverter extends AbstractHttpMessageConverter<Employee> {
public ProductConverter() {
super(new MediaType("application", "json", Charset.forName("UTF-8")));
System.out.println("Created ");
}
#Override
protected boolean supports(Class<?> clazz) {
return false;
}
#Override
protected Employee readInternal(Class<? extends Employee> clazz,
HttpInputMessage inputMessage) throws IOException,
HttpMessageNotReadableException {
InputStream inputStream = inputMessage.getBody();
System.out.println("Test******");
return null;
}
#Override
protected void writeInternal(Employee t,
HttpOutputMessage outputMessage) throws IOException,
HttpMessageNotWritableException {
// TODO Auto-generated method stu
}
}
2: I create a configuration class to register HTTPMessageConverters
#Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter{
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
System.out.println("Configure Message Converters");
converters.add(new ProductConverter());
super.configureMessageConverters(converters);
//super.extendMessageConverters(converters);
}
}
3: The rest class method
#RequestMapping(value="/{categoryId}" ,method=RequestMethod.POST, consumes="application/json")
#PreAuthorize("permitAll")
public ResponseEntity<ProductEntity> saveProduct(#RequestBody Employee employee , #PathVariable Long categoryId) {
logger.log(Level.INFO, "Category Id: {0}" , categoryId);
ResponseEntity<ProductEntity> responseEntity =
new ResponseEntity<ProductEntity>(HttpStatus.OK);
return responseEntity;
}
My Custom HTTPMessageCoverter it's created but is never called ? Is there a configuration or step I'm missing ? any input or advice is appreciated.
After overriding the (AbstractHttpMessageConverter) class methods, I found out there's two annotations for achieving polymorphism #JsonTypeInfo and #JsonSubTypes. For anyone who wants achieve polymorphism can use these two annotations.
I believe you want to configure these message converters using the configureMessageConverters method in a configuration class that extends WebMvcConfigurerAdapter. I've done this myself with a converter for CSV content. I've included that code below. This link shows an example as well. This link may also be helpful. It seems like with Spring configuration it is not always clear on the best place to configure things. :) Let me know if this helps.
#Configuration
public class ApplicationWebConfiguration extends WebMvcConfigurerAdapter {
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
super.configureMessageConverters(converters);
converters.add(new CsvMessageConverter());
}
}
You will also need top modify your supports() method to return true for classes supported by the converter. See the Spring doc for AbstractHttpMessageConverter supports method.