i am not sure my understanding to errorHandler and returnExceptions is right or not.
but here is my goal: i sent a message from App_A, use #RabbitListener to receive message in App_B.
according to the doc
https://docs.spring.io/spring-amqp/docs/2.1.3.BUILD-SNAPSHOT/reference/html/_reference.html#annotation-error-handling
i assume if APP_B has a business exception during process the message,through set errorHandler and returnExceptions in a right way on #RabbitListener can let the exception back to App_A.
do I understood correctly?
if i am rigth, how to use it in a right way?
with my code, i get nothing in APP_A .
here is my code in APP_B
errorHandler:
#Component(value = "errorHandler")
public class ErrorHandler implements RabbitListenerErrorHandler {
#Override
public Object handleError(Message arg0, org.springframework.messaging.Message<?> arg1,
ListenerExecutionFailedException arg2) throws ListenerExecutionFailedException {
throw new ListenerExecutionFailedException("msg", arg2, null);
}
}
RabbitListener:
#RabbitListener(
bindings = #QueueBinding(
value = #Queue(value = "MRO.updateBaseInfo.queue", durable = "true"),
exchange = #Exchange(name = "MRO_Exchange", type = ExchangeTypes.DIRECT, durable = "true"),
key = "baseInfoUpdate"
),
// errorHandler = "errorHandler",
returnExceptions = "true"
)
public void receiveLocationChangeMessage(String message){
BaseUpdateMessage newBaseInfo = JSON.parseObject(message, BaseUpdateMessage.class);
dao.upDateBaseInfo(newBaseInfo);
}
and code in APP_A
#Component
public class MessageSender {
#Autowired
private RabbitTemplate rabbitTemplate;
public void editBaseInfo(BaseUpdateMessage message)throws Exception {
//and i am not sure set RemoteInvocationAwareMessageConverterAdapter in this way is right
rabbitTemplate.setMessageConverter(new RemoteInvocationAwareMessageConverterAdapter());
rabbitTemplate.convertAndSend("MRO_Exchange", "baseInfoUpdate", JSON.toJSONString(message));
}
}
i am very confuse with three points:
1)do i have to use errorHandler and returnExceptions at the same time? i thought errorHandler is something like a postprocessor that let me custom exception.if i don't need a custom exception can i just set returnExceptions with out errorHandler ?
2)should the method annotated with #RabbitListener return something or void is just fine?
3)in the sender side(my situation is APP_A), does have any specific config to catch the exception?
my workspace environment:
Spring boot 2.1.0
rabbitMQ server 3.7.8 on docker
1) No, you don't need en error handler, unless you want to enhance the exception.
2) If the method returns void; the sender will end up waiting for timeout for a reply that will never arrive, just in case an exception might be thrown; that is probably not a good use of resources. It's better to always send a reply, to free up the publisher side.
3) Just the RemoteInvocationAwareMessageConverterAdapter.
Here's an example:
#SpringBootApplication
public class So53846303Application {
public static void main(String[] args) {
SpringApplication.run(So53846303Application.class, args);
}
#RabbitListener(queues = "foo", returnExceptions = "true")
public String listen(String in) {
throw new RuntimeException("foo");
}
#Bean
public ApplicationRunner runner(RabbitTemplate template) {
template.setMessageConverter(new RemoteInvocationAwareMessageConverterAdapter());
return args -> {
try {
template.convertSendAndReceive("foo", "bar");
}
catch (Exception e) {
e.printStackTrace();
}
};
}
}
and
org.springframework.amqp.AmqpRemoteException: java.lang.RuntimeException: foo
at org.springframework.amqp.support.converter.RemoteInvocationAwareMessageConverterAdapter.fromMessage(RemoteInvocationAwareMessageConverterAdapter.java:74)
at org.springframework.amqp.rabbit.core.RabbitTemplate.convertSendAndReceive(RabbitTemplate.java:1500)
at org.springframework.amqp.rabbit.core.RabbitTemplate.convertSendAndReceive(RabbitTemplate.java:1433)
at org.springframework.amqp.rabbit.core.RabbitTemplate.convertSendAndReceive(RabbitTemplate.java:1425)
at com.example.So53846303Application.lambda$0(So53846303Application.java:28)
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:804)
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:794)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:324)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
at com.example.So53846303Application.main(So53846303Application.java:15)
Caused by: java.lang.RuntimeException: foo
at com.example.So53846303Application.listen(So53846303Application.java:20)
As you can see, there is a local org.springframework.amqp.AmqpRemoteException with the cause being the actual exception thrown on the remote server.
Related
I have some basic ExceptionHandler view:
#ParentLayout(MainLayout.class)
#AnonymousAllowed
public class ExceptionHandler extends VerticalLayout implements HasErrorParameter<Exception> {
static final Logger logger = LoggerFactory.getLogger(ExceptionHandler.class);
#Override
public int setErrorParameter(BeforeEnterEvent event, ErrorParameter<Exception> parameter) {
logger.error("Error", parameter.getException());
Label label = new Label(parameter.getException().getMessage());
add(label);
return HttpServletResponse.SC_NOT_FOUND;
}
}
which works fine when error occurs in synchronous calls.
But when I use #Async feature, like for example:
ListenableFuture<DecisionMatrixPage> listenableFuture = container.queryDataAsync();
var ui = UI.getCurrent();
listenableFuture.addCallback(page -> {
ui.access(() -> {
//do something
});
}, err -> {
logger.error("Error", err);
throw new AsyncException("Async error", err);
});
I may only log the error but unfortunately rethrowing of AsyncException is not catched by ExceptionHandler view. How to properly re-throw exception to be catched by ExceptionHandler ?
View implementing HasErrorParameter is used only when exception occurs during navigation. For more general exception handler you need to setup ErrorHandler using VaadinSession#setErrorHandler. The right place to setup the error handler is usually in the session init listener.
https://vaadin.com/docs/latest/advanced/session-and-ui-init-listener
I have the following code snipped that creates a TCPServer, and attaches a ChannelHandler to the channel in the doOnChannelInit() function. The server is to process byte data from an embedded device.
#Component
#RequiredArgsConstructor
public class NettyServer {
Logger log = LoggerFactory.getLogger(NettyServer.class);
private final NettyProperties nettyProperties;
private final NettyServerHandler nettyServerHandler;
private TcpServer server;
public void run() {
server = TcpServer
.create()
.host("localhost")
.port(nettyProperties.getTcpPort())
.doOnChannelInit((connectionObserver, channel, remoteAddress) -> {
log.info("Connection from " + remoteAddress);
channel.pipeline()
.addLast("idleStateHandler", new IdleStateHandler(0, 0, 4, TimeUnit.MINUTES))
.addLast(new ByteArrayDecoder())
.addLast(new ByteArrayEncoder())
.addLast(nettyServerHandler);
});
server.bindNow();
log.info("Server running");
}
}
Channel handler
#Component
#RequiredArgsConstructor
#ChannelHandler.Sharable
public class NettyServerHandler extends SimpleChannelInboundHandler<byte[]> {
Logger log = LoggerFactory.getLogger(NettyServerHandler.class);
private final AttributeKey<byte[]> dataKey = AttributeKey.valueOf("dataBuf");
private final AttributeKey<Integer> dataLen = AttributeKey.valueOf("dataBufLen");
#Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
log.info("New Meter connection from : " + ctx.channel());
}
#Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
if (ctx.channel() != null) {
log.info(String.format("Meter/Client Disconnected. No: %s ; Channel : %s", meterNo, ctx.channel()));
}
ctx.close();
}
#Override
protected void channelRead0(ChannelHandlerContext ctx, byte[] msg) throws Exception {
log.info("Message received: " + new String(msg);
ctx.channel().read();
}
}
I'm able to connect to the server, but when i send a message, nothing happens, the log statements are not triggered.
I'm not sure what I'm missing here, would appreciate some help.
Thanks
There is no need to add custom handlers to the Netty pipeline. The example above can be written like this:
#Component
#RequiredArgsConstructor
public class NettyServer {
Logger log = LoggerFactory.getLogger(NettyServer.class);
private final NettyProperties nettyProperties;
private TcpServer server;
public void run() {
server = TcpServer
.create()
.host("localhost")
.port(nettyProperties.getTcpPort())
.doOnChannelInit((connectionObserver, channel, remoteAddress) -> {
log.info("Connection from " + remoteAddress);
channel.pipeline()
.addLast("idleStateHandler", new IdleStateHandler(0, 0, 4, TimeUnit.MINUTES));
})
.handle((in, out) ->
in.receive()
.asString()
.doOnNext(s -> log.info("Message received: " + s))
.then());
server.bindNow();
log.info("Server running");
}
}
Consider checking the Reference Documentation
The incoming data can be transformed to String with (asString), to byte[] with (asByteArray) etc. If there is no suitable transformation you can use map(byteBuf -> ...) and transform the ByteBuf to the needed abstraction.
As per doc, defaultRequeueRejected's default value is true, but looking at code it seems its false. I am not sure if I am missing anything or we have to change that in SimpleRabbitListenerContainerFactory.java
EDIT
Sample code, after putting message in test queue, I expect it to stay in queue since its failing but it is throwing it out. I want message to be retried so I configured that in container factory if it fails after retry I want it to be back in queue. I am sure I am missing understanding here.
#SpringBootApplication
public class MsgRequeExampleApplication {
public static void main(String[] args) {
SpringApplication.run(MsgRequeExampleApplication.class, args);
}
#Bean(name = "myContainerFactory")
public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory(ConnectionFactory connectionFactory) {
SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
factory.setConnectionFactory(connectionFactory);
factory.setMessageConverter(new Jackson2JsonMessageConverter());
factory.setMissingQueuesFatal(false);
FixedBackOffPolicy backOffPolicy = new FixedBackOffPolicy();
backOffPolicy.setBackOffPeriod(500);
factory.setAdviceChain(new Advice[] { org.springframework.amqp.rabbit.config.RetryInterceptorBuilder.stateless()
.maxAttempts(2).backOffPolicy(backOffPolicy).build() });
return factory;
}
#RabbitListener(queues = "test", containerFactory = "myContainerFactory")
public void processAdvisory(Message message) throws MyBusinessException {
try{
//Simulating exception while processing message
String nullString=null;
nullString.length();
}catch(Exception ex){
throw new MyBusinessException(ex.getMessage());
}
}
public class MyBusinessException extends Exception {
public MyBusinessException(String msg) {
super(msg);
}
}
}
There is a good description in the SimpleMessageListenerContainer JavaDocs:
/**
* Set the default behavior when a message is rejected, for example because the listener
* threw an exception. When true, messages will be requeued, when false, they will not. For
* versions of Rabbit that support dead-lettering, the message must not be requeued in order
* to be sent to the dead letter exchange. Setting to false causes all rejections to not
* be requeued. When true, the default can be overridden by the listener throwing an
* {#link AmqpRejectAndDontRequeueException}. Default true.
* #param defaultRequeueRejected true to reject by default.
*/
public void setDefaultRequeueRejected(boolean defaultRequeueRejected) {
this.defaultRequeueRejected = defaultRequeueRejected;
}
Does it make sense to you?
UPDATE
To requeue after retry exhausting you need to configure some custom MessageRecoverer on the RetryInterceptorBuilder with the code like:
.recoverer((message, cause) -> {
ReflectionUtils.rethrowRuntimeException(cause);
})
This way the exception will be thrown to the listener container and according its defaultRequeueRejected the message will be requeued or not.
I've been experiencing troubles with spring-boot consumer. I compared the work of two consumers.
First consumer:
import com.rabbitmq.client.*;
import java.io.IOException;
public class Recv {
private final static String QUEUE_NAME = "hello";
public static void main(String[] argv) throws Exception {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
Consumer consumer = new DefaultConsumer(channel) {
#Override
public void handleDelivery(String consumerTag, Envelope envelope,
AMQP.BasicProperties properties, byte[] body) throws IOException {
}
};
channel.basicConsume(QUEUE_NAME, true, consumer);
}
}
Second consumer:
#Controller
public class Consumer {
#RabbitListener(queues = "hello")
public void processMessage(Message message) {
}
}
There are no config files for spring-boot consumer installed, everything goes by default.
On my computer first one works 10 times faster. What might be the problem?
The default prefetch (basicQos) for Spring AMQP consumers is 1 which means only 1 message is outstanding at the consumer at any one time; configure the rabbitListenerContainerFactory #Bean to set the prefetchCount to something larger.
You will have to override the default boot-configured #Bean.
Hi friends i am trying to read incoming sms but getting warning like this . Invocation of questionable method: java.lang.String.(String) found in: mypackage.MyApp$ListeningThread.run()
Here is my code is
public class MyApp extends UiApplication {
//private ListeningThread listener;
public static void main(String[] args) {
MyApp theApp = new MyApp();
theApp.enterEventDispatcher();
}
public MyApp() {
invokeAndWait(new Runnable() {
public void run() {
ListeningThread listener = new ListeningThread();
listener.start();
}
});
pushScreen(new MyScreen());
}
private static class ListeningThread extends Thread {
private boolean _stop = false;
private DatagramConnection _dc;
public synchronized void stop() {
_stop = true;
try {
_dc.close(); // Close the connection so the thread returns.
} catch (IOException e) {
System.err.println(e.toString());
}
}
public void run() {
try {
_dc = (DatagramConnection) Connector.open("sms://");
for (;;) {
if (_stop) {
return;
}
Datagram d = _dc.newDatagram(_dc.getMaximumLength());
_dc.receive(d);
String address = new String(d.getAddress());
String msg = new String(d.getData());
if(msg.startsWith("START")){
Dialog.alert("hello");
}
System.out.println("Message received: " + msg);
System.out.println("From: " + address);
System.exit(0);
}
} catch (IOException e) {
System.err.println(e.toString());
}
}
}
}
Please correct me where i am wrong.Is possible give me some code to read incoming sms content in blackberry.
A few points about your code:
That invokeAndWait call to launch a thread makes no sense. It doesn't harm, but is kind of waste. Use that method only to perform UI related operations.
You should try using "sms://:0" as param for Connector.open. According to the docs, a parameter with the form {protocol}://[{host}]:[{port}] will open the connection in client mode (which makes sense, since you are on the receiving part), whereas not including the host part will open it in server mode.
Finally, if you can't get it working, you could use instead the third method specified in this tutorial, which you probably have already read.
The error you quoted is complaining about the use of the String constructor that takes a string argument. Since strings are immutable in Java-ME, this is just a waste. You can use the argument string directly:
Invocation of questionable method: java.lang.String.(String) found in: mypackage.MyApp$ListeningThread.run()
//String address = new String(d.getAddress());
String address = d.getAddress();
// getData() returns a byte[], so this is a different constructor
// However, this leaves the character encoding unspecified, so it
// will default to cp1252, which may not be what you want
String msg = new String(d.getData());