问题
I am implementing Oracle Advanced Queue and am completely new to it. I have a few doubts regarding it. Below is my code:
package com;
/* Set up main class from which we will call subsequent examples and handle
exceptions: */
import java.sql.*;
import oracle.AQ.*;
public class test_aqjava
{
public static void main(String args[])
{
AQSession aq_sess = null;
try
{
aq_sess = createSession(args);
createAqTables(aq_sess);
enqueueMsg(aq_sess);
// dequeueMsg(aq_sess);
aq_sess.close();
/* now run the test: */
// runTest(aq_sess);
}
catch (Exception ex)
{
System.out.println("Exception-1: " + ex);
ex.printStackTrace();
}
}
public static AQSession createSession(String args[])
{
Connection db_conn;
AQSession aq_sess = null;
try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
/* your actual hostname, port number, and SID will
vary from what follows. Here we use 'dlsun736,' '5521,'
and 'test,' respectively: */
db_conn =
DriverManager.getConnection(
"jdbc:oracle:thin:@hostname.com:1521:sid",
"USER", "USER");
System.out.println("JDBC Connection opened ");
db_conn.setAutoCommit(false);
/* Load the Oracle8i AQ driver: */
Class.forName("oracle.AQ.AQOracleDriver");
/* Creating an AQ Session: */
aq_sess = AQDriverManager.createAQSession(db_conn);
System.out.println("Successfully created AQSession ");
}
catch (Exception ex)
{
System.out.println("Exception: " + ex);
ex.printStackTrace();
}
return aq_sess;
}
public static void createAqTables(AQSession aq_sess) throws AQException
{
AQQueueTableProperty qtable_prop;
AQQueueProperty queue_prop;
AQQueueTable q_table;
AQQueue queue;
/* Creating a AQQueueTableProperty object (payload type - RAW): */
qtable_prop = new AQQueueTableProperty("RAW");
/* Creating a queue table called aq_table1 in aqjava schema: */
q_table = aq_sess.createQueueTable ("USER", "aq_table1", qtable_prop);
System.out.println("Successfully created aq_table1 in aqjava schema");
/* Creating a new AQQueueProperty object */
queue_prop = new AQQueueProperty();
/* Creating a queue called aq_queue1 in aq_table1: */
queue = aq_sess.createQueue (q_table, "aq_queue1", queue_prop);
System.out.println("Successfully created aq_queue1 in aq_table1");
/* Enable enqueue/dequeue on this queue: */
queue.start();
System.out.println("Successful start queue");
}
public static void enqueueMsg(AQSession aq_sess) throws AQException
{
AQQueueTable q_table;
AQQueue queue;
AQMessage message;
AQRawPayload raw_payload;
AQEnqueueOption enq_option;
String test_data = "new message";
byte[] b_array;
Connection db_conn;
db_conn = ((AQOracleSession)aq_sess).getDBConnection();
/* Get a handle to queue table - aq_table4 in aqjava schema: */
q_table = aq_sess.getQueueTable ("USER", "aq_table1");
System.out.println("Successful getQueueTable");
/* Get a handle to a queue - aq_queue4 in aquser schema: */
queue = aq_sess.getQueue ("USER", "aq_queue1");
System.out.println("Successful getQueue");
/* Creating a message to contain raw payload: */
message = queue.createMessage();
/* Get handle to the AQRawPayload object and populate it with raw data: */
b_array = test_data.getBytes();
raw_payload = message.getRawPayload();
raw_payload.setStream(b_array, b_array.length);
/* Creating a AQEnqueueOption object with default options: */
enq_option = new AQEnqueueOption();
/* Enqueue the message: */
queue.enqueue(enq_option, message);
try {
db_conn.commit();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void dequeueMsg(AQSession aq_sess) throws AQException
{
AQQueueTable q_table;
AQQueue queue;
AQMessage message;
AQRawPayload raw_payload;
AQDequeueOption deq_option;
byte[] b_array;
Connection db_conn;
db_conn = ((AQOracleSession)aq_sess).getDBConnection();
/* Get a handle to queue table - aq_table4 in aqjava schema: */
q_table = aq_sess.getQueueTable ("USER", "aq_table1");
System.out.println("Successful getQueueTable");
/* Get a handle to a queue - aq_queue4 in aquser schema: */
queue = aq_sess.getQueue ("USER", "aq_queue1");
System.out.println("Successful getQueue");
/* Creating a AQDequeueOption object with default options: */
deq_option = new AQDequeueOption();
/* Enqueue the message: */
message = queue.dequeue(deq_option);
raw_payload = message.getRawPayload();
b_array= raw_payload.getBytes();
String msg = new String(b_array);
System.out.println("Dequeue Msg "+msg);
try {
db_conn.commit();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
I have created a Queue Table and a Queue. Message was written and read from the queue.
Q1. Can i write one more message to the same queue and read from it? If yes, how do we do it? BecauseI tried writing message to the same queue but couldn't
Q2. How do I convert my above code into publish-subscribe? How can I test it by reading the same message multiple times?
Any help appreciated.
回答1:
1) Log to oracle db and create user.
CREATE USER jmsuser IDENTIFIED BY a;
GRANT DBA, AQ_ADMINISTRATOR_ROLE, AQ_USER_ROLE to jmsuser;
GRANT EXECUTE ON DBMS_AQADM TO jmsuser;
GRANT EXECUTE ON DBMS_AQ TO jmsuser;
GRANT EXECUTE ON DBMS_LOB TO jmsuser;
GRANT EXECUTE ON DBMS_JMS_PLSQL TO jmsuser;
2) Class creates multiconsumer queue and registers two subscriber for queue. (ConnectionDefinition.getOracleConnection() return regular jdbc connection to oracle)
import java.sql.Connection;
import oracle.AQ.AQAgent;
import oracle.AQ.AQDriverManager;
import oracle.AQ.AQQueue;
import oracle.AQ.AQQueueProperty;
import oracle.AQ.AQQueueTable;
import oracle.AQ.AQQueueTableProperty;
import oracle.AQ.AQSession;
/**
*
* @author alukasiewicz
*/
public class NewClass {
public static void main(String[] args) throws Exception {
Class.forName("oracle.AQ.AQOracleDriver");
Connection con = ConnectionDefinition.getOracleConnection();
AQSession aq_sess = AQDriverManager.createAQSession(con);
AQQueueTableProperty qtable_prop;
AQQueueProperty queue_prop;
AQQueueTable q_table;
AQQueue queue;
AQAgent subs1, subs2;
qtable_prop = new AQQueueTableProperty("SYS.AQ$_JMS_BYTES_MESSAGE");
qtable_prop.setMultiConsumer(true);
q_table = aq_sess.createQueueTable("jmsuser", "aq_table5", qtable_prop);
queue_prop = new AQQueueProperty();
queue = aq_sess.createQueue(q_table, "aq_queue5", queue_prop);
System.out.println("Successful createQueue");
System.out.println("Successful start queue");
subs1 = new AQAgent("GREEN", "", 0);
subs2 = new AQAgent("BLUE", "", 0);
queue.addSubscriber(subs2, null);
queue.addSubscriber(subs1, null);
queue.start();
}
}
3) Class publishes messages to queue.
public class Publisher {
public static void main(String[] args) throws Exception {
Class.forName("oracle.AQ.AQOracleDriver");
Connection con = ConnectionDefinition.getOracleConnection();
TopicConnection tc_conn =AQjmsTopicConnectionFactory.createTopicConnection(con);
tc_conn.start();
TopicSession jms_sess = tc_conn.createTopicSession(true, Session.SESSION_TRANSACTED);
Topic queueTopic= ((AQjmsSession )jms_sess).getTopic("JMSUSER","AQ_QUEUE5");
AQjmsTopicPublisher publisherAq = (AQjmsTopicPublisher)jms_sess.createPublisher(queueTopic);
BytesMessage messAll = jms_sess.createBytesMessage();
BytesMessage messOnlyForGreen = jms_sess.createBytesMessage();
messAll.writeUTF("Message for all subscribers");
messOnlyForGreen.writeUTF("Message only for green");
publisherAq.publish(messAll);
publisherAq.publish(messOnlyForGreen, new AQjmsAgent[]{new AQjmsAgent("GREEN", null)} );
con.commit();
tc_conn.close();
con.close();
}
}
In oracle you can view these messages in queue. Two for green one for red.
SELECT a.queue, a.msg_state, a.consumer_name FROM jmsuser.aq$aq_table5 a
4) Class reads message from queue;
public class Subscriber {
public static void main(String[] args) throws Exception {
Class.forName("oracle.AQ.AQOracleDriver");
Connection con = ConnectionDefinition.getOracleConnection();
TopicConnection tc_conn = AQjmsTopicConnectionFactory.createTopicConnection(con);
TopicSession jms_sess = tc_conn.createTopicSession(true, Session.SESSION_TRANSACTED);
tc_conn.start();
Topic queueTopic = ((AQjmsSession) jms_sess).getTopic("jmsuser", "AQ_QUEUE5");
TopicSubscriber subGreen = (TopicSubscriber)((AQjmsSession) jms_sess).createDurableSubscriber(queueTopic, "GREEN");
TopicSubscriber subRed = (TopicSubscriber)((AQjmsSession) jms_sess).createDurableSubscriber(queueTopic, "RED");
Message msg = subGreen.receive(10);
System.err.println("Start receiving message for green subscriber");
while(msg != null){
System.err.println(" GREEN recive message "+ ((BytesMessage)msg).readUTF());
msg = subGreen.receive(10); // receive with timeout;
}
System.err.println("End receiving message for green subscriber");
System.err.println(" ");
System.err.println("Start receiving message for red subscriber");
BytesMessage byteMsg = (BytesMessage)msg;
msg = subRed.receive(10);
while(msg != null){
System.err.println(" RED recive message "+ ((BytesMessage)msg).readUTF());
msg = subRed.receive(10); // receive with timeout;
}
System.err.println("End receiving message for red subscriber");
con.commit();
tc_conn.close();
con.close();
}
}
5) Pom dependencies
<dependencies>
<dependency>
<groupId>com.oracle</groupId>
<artifactId>ojdbc6</artifactId>
<version>11.2.0.4</version>
</dependency>
<dependency>
<groupId>com.oracle</groupId>
<artifactId>aqapi</artifactId>
<version>13</version>
</dependency>
<dependency>
<groupId>javax.jms</groupId>
<artifactId>jms</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>javax.transaction</groupId>
<artifactId>jta</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>com.oracle</groupId>
<artifactId>orai18n</artifactId>
<version>11.2.0.4</version>
</dependency>
</dependencies>
回答2:
Your queue is multconsumer queue with two registered subscriber("SUB1", "SUB2").
1) Enqueue message to queue without specify subscriber.
2) The message will be replicated for all subscribers.
It possible to check this through select from select consumer_name from aq$queue_table_name;
Query should return SUB1 and SUB2.
3) You don't need to notify subscribers. All subscribers listen on queue and they are waiting for theirs message
Oracle has very useful manual Streams Advanced Queuing User's Guide
来源：https://stackoverflow.com/questions/31405940/oracle-advanced-queue-in-java