[英]Consuming JMS with a multi-threaded client
我正在尝试使用多个线程来消耗jms队列。 我知道每个线程应该有一个单独的JMS会话,并且我在代码中所做的工作如下所示。 但是我得到一个奇怪的例外
这是异常堆栈跟踪:
javax.jms.IllegalStateException: Forbidden call on a closed connection.
at org.objectweb.joram.client.jms.Connection.checkClosed(Connection.java:404)
at org.objectweb.joram.client.jms.Connection.createSession(Connection.java:530)
at MessageWorker.run(ReceiveJmsDemoMultiThreaded.java:96)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
我需要您的帮助,因为这对我来说是个难题
import java.util.Properties;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.QueueConnectionFactory;
import javax.jms.Session;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class ReceiveJmsDemoMultiThreaded {
public static void main(String[] args) {
Context context = null;
ConnectionFactory factory = null;
Connection connection = null;
Destination destination = null;
try {
context = getInitialContext();
factory = (QueueConnectionFactory) context.lookup("JQCF");
destination = (Destination) context.lookup("sampleQueue");
connection = factory.createConnection();
final ExecutorService executor = Executors.newCachedThreadPool();
executor.submit(new MessageWorker(connection, destination) );
executor.submit(new MessageWorker(connection, destination) );
executor.submit(new MessageWorker(connection, destination) );
executor.submit(new MessageWorker(connection, destination) );
connection.start();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (context != null) {
try {
context.close();
} catch (NamingException e) {
e.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (JMSException e) {
e.printStackTrace();
}
}
}
}
private static InitialContext getInitialContext() throws NamingException {
Properties prop = new Properties();
prop.put("java.naming.provider.url", "rmi://localhost:1099");
prop.put("java.naming.factory.initial",
"org.objectweb.carol.jndi.spi.MultiOrbInitialContextFactory");
return new InitialContext(prop);
}
}
class MessageWorker extends Thread {
Connection connection = null;
Destination dest = null;
Session session = null;
Destination destination = null;
public MessageWorker(Connection connection, Destination dest) {
this.connection = connection;
this.destination = dest;
}
@Override
public void run() {
try {
MessageConsumer receiver = null;
System.out.println("Starting Thread "+currentThread().getName());
while (true) {
try {
System.out.println("Waiting for next msg "+currentThread().getName());
session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
receiver = session.createConsumer(destination);
Message msg = receiver.receive();
if (msg instanceof Message && msg != null) {
System.out.println("STARTING consuming "+msg.toString()+" by thread "+currentThread().getName() );
Thread.sleep(2000);//some work here
System.out.println("ENDING consuming "+msg.toString()+" by thread "+currentThread().getName() );
}
} catch (JMSException e) {
e.printStackTrace();
System.exit(1);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
}
非常感谢
您正在看到此问题,因为在主线程中,将作业提交给Executor服务后,使用以下命令关闭了连接:
connection.close();
因此,当线程尝试使用此共享连接(刚刚关闭)创建Session时,就会收到此异常。 这里没有什么意外的。 仅出于测试目的,您可以使主线程长时间睡眠,直到所有线程都完成接收消息为止。 这样,您可以确认您没有收到此异常。
真正的解决方案可能是关闭Executor服务,并使主线程awaitTermination()
等待提交的作业完成。
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