Freemarker静态化ActiveMQ实现

素颜马尾好姑娘i 2022-05-16 09:24 195阅读 0赞

### Freemarker ###

实现商品页面静态化

ActiveMQ  
使用topic模式，添加商品时  
监听到消息，根据商品id  
从数据库中查询商品信息，生成静态页面

注意  
不从redis中获取商品信息  
添加商品时，redis没有该商品信息  
根据商品id，从数据库中查询商品信息

不直接传递商品信息，而是根据id，从数据库中查询  
因为，不在一个项目中，静态化页面是一个独立的项目  
传输数据的效率不高，修改商品信息时，也需要更新静态页面

### 引入ActiveMQ ###

<dependency>
        <groupId>org.apache.activemq</groupId>
        <artifactId>activemq-all</artifactId>
    </dependency>

### 监听器 ###

ItemAddMesssageListener
    public class ItemAddMesssageListener implements MessageListener { 
    
        @Autowired
        private ItemService itemService;
        @Autowired
        private FreeMarkerConfigurer freeMarkerConfigurer;
        @Value("${HTML_OUT_PATH}")
        private String HTML_OUT_PATH;
        @Override
        public void onMessage(Message message) {
            try {
                //从消息中取商品id
                TextMessage textMessage = (TextMessage) message;
                String strId = textMessage.getText();
                Long itemId = Long.parseLong(strId);
                //等待事务提交
                Thread.sleep(1000);
                //根据商品id查询商品信息及商品描述
                TbItem tbItem = itemService.getItemById(itemId);
                Item item = new Item(tbItem);
                TbItemDesc itemDesc = itemService.getItemDescById(itemId);
                //使用freemarker生成静态页面
                Configuration configuration = freeMarkerConfigurer.getConfiguration();
                //1.创建模板
                //2.加载模板对象
                Template template = configuration.getTemplate("item.ftl");
                //3.准备模板需要的数据
                Map data = new HashMap<>();
                data.put("item", item);
                data.put("itemDesc", itemDesc);
                //4.指定输出的目录及文件名
                Writer out = new FileWriter(new File(HTML_OUT_PATH + strId + ".html"));
                //5.生成静态页面
                template.process(data, out);
                //关闭流
                out.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

### 配置监听器 ###

springmvc-activemq.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.2.xsd">
    
        
        <bean id="targetConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
            <constructor-arg name="brokerURL" value="tcp://192.168.25.168:61616"/>
        </bean>
        
        <bean id="connectionFactory" class="org.springframework.jms.connection.SingleConnectionFactory">
            <property name="targetConnectionFactory" ref="targetConnectionFactory"></property>
        </bean>
    
        <bean id="itemAddTopic" class="org.apache.activemq.command.ActiveMQTopic">
            <constructor-arg name="name" value="item-add-topic"></constructor-arg>
        </bean>
        <bean id="itemAddMessageListener" class="com.taotao.item.listener.ItemAddMesssageListener"/>
        <bean class="org.springframework.jms.listener.DefaultMessageListenerContainer">
            <property name="connectionFactory" ref="connectionFactory" />
            <property name="destination" ref="itemAddTopic" />
            <property name="messageListener" ref="itemAddMessageListener" />
        </bean>
    </beans>

### 加载配置文件 ###

Web.xml中配置Servlet

<servlet>
        <servlet-name>taotao-item-web</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/springmvc*.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>