ActiveMQ---遇到的args输入问题

最新推荐文章于 2023-09-05 00:14:53 发布

猫有很多毛

最新推荐文章于 2023-09-05 00:14:53 发布

阅读量372

点赞数 1

CC 4.0 BY-SA版权

文章标签： activemq

本文链接：https://blog.youkuaiyun.com/qq_34593637/article/details/58599846

在学习ActiveMQ过程中，遇到Pub/Sub示例程序运行不显示股票信息的问题。经检查发现，程序需要通过args参数接收输入，而非控制台直接输入。解决办法是在Eclipse中设置Run Configuration的Arguments选项，将参数添加到Program arguments内，每个参数间以空格分隔。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

最近在学习ActiveMQ，书上一个例子是演示pub/sub原理的stock portfolio.奇怪的是，运行Publisher后控制台只显示连接成功的信息，并没有哗哗哗地刷股票信息。
仔细看了主函数后才发现它是要有输入的，但不是运行后从控制台输入。而是通过args输入。

Publisher主函数代码如下

import java.util.Hashtable;
import java.util.Map;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MapMessage;
import javax.jms.Message;
import javax.jms.MessageProducer;
import javax.jms.Session;

import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQMapMessage;

public class Publisher {

    protected int MAX_DELTA_PERCENT = 1;
    protected Map<String, Double> LAST_PRICES = new Hashtable<String, Double>();//前一次的股票价格
    protected static int count = 10;
    protected static int total;

    protected static String brokerURL = "tcp://localhost:61616";
    protected static transient ConnectionFactory factory;
    protected transient Connection connection;
    protected transient Session session;
    protected transient MessageProducer producer;

    public Publisher() throws JMSException {
        factory = new ActiveMQConnectionFactory(brokerURL);
        connection = factory.createConnection();
        try {
        connection.start();
        } catch (JMSException jmse) {
            connection.close();
            throw jmse;
        }
        session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        producer = session.createProducer(null);
    }

    public void close() throws JMSException {
        if (connection != null) {
            connection.close();
        }
    }

    public static void main(String[] args) throws JMSException {
        Publisher publisher = new Publisher();
        while (total < 1000) {
            for (int i = 0; i < count; i++) {
                publisher.sendMessage(args);
            }
            total += count;
            System.out.println("Published '" + count + "' of '" + total + "' price messages");
            try {
              Thread.sleep(1000);
            } catch (InterruptedException x) {
            }
        }
        publisher.close();
    }

    protected void sendMessage(String[] stocks) throws JMSException {
        int idx = 0;
        while (true) {
            idx = (int)Math.round(stocks.length * Math.random());
            if (idx < stocks.length) {
                break;
            }
        }
        String stock = stocks[idx];
        Destination destination = session.createTopic("STOCKS." + stock);
        Message message = createStockMessage(stock, session);
        System.out.println("Sending: " + ((ActiveMQMapMessage)message).getContentMap() + " on destination: " + destination);
        producer.send(destination, message);
    }

    protected Message createStockMessage(String stock, Session session) throws JMSException {
        Double value = LAST_PRICES.get(stock);
        if (value == null) {
            value = new Double(Math.random() * 100);
        }

        // lets mutate the value by some percentage
        double oldPrice = value.doubleValue();
        value = new Double(mutatePrice(oldPrice));
        LAST_PRICES.put(stock, value);
        double price = value.doubleValue();

        double offer = price * 1.001;

        boolean up = (price > oldPrice);

        MapMessage message = session.createMapMessage();
        message.setString("stock", stock);
        message.setDouble("price", price);
        message.setDouble("offer", offer);
        message.setBoolean("up", up);
        return message;
    }

    protected double mutatePrice(double price) {
        double percentChange = (2 * Math.random() * MAX_DELTA_PERCENT) - MAX_DELTA_PERCENT;

        return price * (100 + percentChange) / 100;
    }

}

eclipse添加args参数的方法
1.右击执行文件，如本例中的Publisher.java
run as 选中 Run Configuration…

2.选中第二个标签Arguments,在Program argument 内输入参数
参数用空格隔开

简单的例子

public class test {
    public static void main(String[] args){
        for(String str:args){
            System.out.println(str);
        }
    }
}