上文主要简单地将activeMq搭建了起来，并且可以用web console去登录查看相关的后台功能。
本文将学习如何用java语言实现一个生产者客户端，主要参考了以下链接：
http://activemq.apache.org/jndi-support.html
代码已上传github，建议先下载下来实际运行一遍：
https://github.com/cctvckl/big-data-learning/tree/master/activemq-learning
一、ActiveMq支持的协议
ActiveMq作为消息中间件，支持多种连接协议，如：tcp、amqp、stomp、mqtt等。
如果启动时以./activemq console方式启动，可以看到如下输出：
而下文将要讲解的java客户端程序，就是基于其中的tcp协议。
将tcp://host:port这个地址记录下来，下面需要用到。
二、大体思路
1、本地配置文件，配置要连接的ActiveMq服务器、包括连接协议和端口号，配置要发送消息的目标队列、目标topic等等。
2、程序读取上述配置文件，生成连接会话、生成消息生产者、发送消息、关闭连接。
三、具体步骤
1、配置文件样例：
java.naming.factory.initial = org.apache.activemq.jndi.ActiveMQInitialContextFactory
# Use the following property to configure the default connector
java.naming.provider.url = tcp://192.168.2.140:61616
# Use the following property to specify the JNDI name the connection factory
# should appear as.
connectionFactoryNames = ConnectionFactory, queueConnectionFactory, topicConnectionFactry
# Register some queues in JNDI using the form:
# queue.[jndiName] = [physicalName]
queue.MyQueue = example.MyQueue
# Register some topics in JNDI using the form:
# topic.[jndiName] = [physicalName]
topic.MyTopic = example.MyTopic
释义：上面的url项要与第一章节里面的那个地址匹配；
topic.MyTopic中的点号分割开的第二部分（此例为MyTopic）会被注册为JNDI名, 至于value（example.MyTopic）为topic名，在Web Console可以看到。
queue.MyQueue同理。
2、配置文件完毕，下面介绍业务代码：
package com.ckl.activemq;
/**
* The SimpleQueueSender class consists only of a main method,
* which sends several messages to a queue.
*
* Run this program in conjunction with SimpleQueueReceiver.
* Specify a queue name on the command line when you run the
* program. By default, the program sends one message. Specify
* a number after the queue name to send that number of messages.
*/
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.jms.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
/**
* A simple polymorphic JMS producer which can work with Queues or Topics which
* uses JNDI to lookup the JMS connection factory and destination.
*/
public class SimpleProducer {
private static final Logger LOG = LoggerFactory.getLogger(SimpleProducer.class);
private SimpleProducer() {}
/**
* @param args the destination name to send to and optionally, the number of
* messages to send
*/
public static void main(String[] args) {
Context jndiContext = null;
ConnectionFactory connectionFactory = null;
Connection connection = null;
Session session = null;
Destination destination = null;
MessageProducer producer = null;
String destinationName = null;
final int numMsgs;
//这边被我手动修改了，比较不喜欢每次运行时还要修改Run configuration，麻烦。 args = new String[2];
args[0] = "MyTopic";
args[1] = "3";
if ((args.length < 1) || (args.length > 2)) {
LOG.info("Usage: java SimpleProducer <destination-name> [<number-of-messages>]");
System.exit(1);
}
destinationName = args[0];
LOG.info("Destination name is " + destinationName);
if (args.length == 2) {
numMsgs = (new Integer(args[1])).intValue();
}
else {
numMsgs = 1;
}
/*
* Create a JNDI API InitialContext object
*/
try {
jndiContext = new InitialContext();
}
catch (NamingException e) {
LOG.info("Could not create JNDI API context: " + e.toString());
System.exit(1);
}
/*
* Look up connection factory and destination.
*/
try {
connectionFactory = (ConnectionFactory)jndiContext.lookup("ConnectionFactory");
destination = (Destination)jndiContext.lookup(destinationName);
}
catch (NamingException e) {
LOG.info("JNDI API lookup failed: " + e);
System.exit(1);
}
/*
* Create connection. Create session from connection; false means
* session is not transacted. Create sender and text message. Send
* messages, varying text slightly. Send end-of-messages message.
* Finally, close the connection.
*/
try {
connection = connectionFactory.createConnection();
session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
producer = session.createProducer(destination);
TextMessage message = session.createTextMessage();
for (int i = 0; i < numMsgs; i++) {
message.setText("This is message " + (i + 1));
LOG.info("Sending message: " + message.getText());
producer.send(message);
}
/*
* Send a non-text control message indicating end of messages.
*/
producer.send(session.createMessage());
}
catch (JMSException e) {
LOG.info("Exception occurred: " + e);
}
finally {
//睡眠是我手动加的，主要为了观察效果 try {
Thread.sleep(100000L);
} catch (InterruptedException e) {
e.printStackTrace();
}
if (connection != null) {
try {
connection.close();
}
catch (JMSException ignored) {}
}
}
}
}
代码不难理解：jndi读取配置文件，建立连接，发消息，关闭连接。
运行结果：
此时查看Web Console，
可以看到来自客户端的连接信息。
本例子就先到这里，详细还请参考贴的代码链接和官网文档。
欢迎留言交流。