Camel In Action 讀書筆記 (3)

時間 2019-11-10

標籤 camel action 讀書筆記简体版

原文原文鏈接

在第二章開始講Camel的路由配置以及路由經常使用模式。 <h3>Camel的路由配置有三種方式：</h3> 1.java DSL （純java方式）建立RouteBuilder <a href="http://static.oschina.net/uploads/img/201306/02141322_TlsL.png"><img style="background-image: none; border-right-width: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141325_BcWq.png" width="414" height="224" /></a> 2.Spring DSL（純spring方式） <a href="http://static.oschina.net/uploads/img/201306/02141326_P36Q.png"><img style="background-image: none; border-right-width: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141327_epoH.png" width="439" height="123" /></a> 3.定義bean的形式（Java+Spring） <a href="http://static.oschina.net/uploads/img/201306/02141327_AfZO.png"><img style="background-image: none; border-right-width: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141328_Cb1c.png" width="434" height="73" /></a> <h3>路由經常使用模式</h3> <h4>1.Using a content-based router（基於內容的路由）</h4> <a href="http://static.oschina.net/uploads/img/201306/02141329_WHi6.png"><img style="background-image: none; border-bottom: 0px; border-left: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top: 0px; border-right: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141331_q8JC.png" width="547" height="254" /></a> 如上圖：路由到下一個節點時須要根據文件類型來判斷是xmlOrders仍是csvOrdersks能夠經過choice…..when的形式來定義 headerCamel的表達式經常使用的有constant,simple,header,body. from("jms:incomingOrders")       .choice()                                   .when(header("CamelFileName")     .endsWith(".xml"))                   .to("jms:xmlOrders")         .when(header("CamelFileName")     .endsWith(".csv"))                   .to("jms:csvOrders");      <h4>2.Using message filters（消息過濾）</h4> <a href="http://static.oschina.net/uploads/img/201306/02141331_5dM8.png"><img style="background-image: none; border-bottom: 0px; border-left: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top: 0px; border-right: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141333_pQrg.png" width="496" height="159" /></a> 如上圖：若是消息(xml)order節點包含test屬性則自動過濾掉。經過filter處理，若是是xml形式的消息可用xpath來解析消息 <route>   <from uri="jms:xmlOrders"/>   <filter>     <xpath>/order[not(@test)]</xpath>     <process ref="orderLogger"/>   </filter> </route> <h4>3.Using multicasting（多點廣播）</h4> <a href="http://static.oschina.net/uploads/img/201306/02141334_DNiE.png"><img style="background-image: none; border-bottom: 0px; border-left: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top: 0px; border-right: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141335_FVRt.png" width="483" height="164" /></a> 如上圖，xmlOrders收到的消息要同時發送到accounting和production兩個隊列中去。經過multicast()來實現。 ExecutorService executor = Executors.newFixedThreadPool(16); from("jms:xmlOrders")    .multicast().parallelProcessing().executorService(executor)     .to("jms:accounting", "jms:production"); 注：能夠不指定線程池，系統默認會建立一個線程池大小爲10： from("jms:xmlOrders")     .multicast().parallelProcessing()     .to("jms:accounting", "jms:production"); <h4>4.Using recipient lists（收件人列表模式）</h4> <a href="http://static.oschina.net/uploads/img/201306/02141336_P3Wu.png"><img style="background-image: none; border-bottom: 0px; border-left: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top: 0px; border-right: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141336_hjv7.png" width="457" height="200" /></a> 如上圖，根據收件人列表來決定發送到哪些消息隊列中去。 from("jms:xmlOrders") .setHeader("customer", xpath("/order/@customer")) .process(new Processor() {     public void process(Exchange exchange) throws Exception {         String recipients = "jms:accounting";         String customer =             exchange.getIn().getHeader("customer", String.class);         if (customer.equals("honda")) {             recipients += ",jms:production";         }         exchange.getIn().setHeader("recipients", recipients);     } }) .recipientList(header("recipients")); recipientList也支持註解的形式： from("jms:xmlOrders").bean(RecipientListBean.class); public class RecipientListBean {     @RecipientList     public String[] route(@XPath("/order/@customer") String customer) {         if (isGoldCustomer(customer)) {             return new String[] {"jms:accounting", "jms:production"};         } else {             return new String[] {"jms:accounting"};         }     }     private boolean isGoldCustomer(String customer) {         return customer.equals("honda");     } } <h4>6.Using the wireTap method（消息監聽，複製）</h4> <a href="http://static.oschina.net/uploads/img/201306/02141337_3IY8.png"><img style="background-image: none; border-bottom: 0px; border-left: 0px; padding-left: 0px; padding-right: 0px; display: inline; border-top: 0px; border-right: 0px; padding-top: 0px" title="image" border="0" alt="image" src="http://static.oschina.net/uploads/img/201306/02141338_SxxA.png" width="408" height="196" /></a> 如上圖，在消息送到目的地的過程當中對消息複製一份送到Tapdestination. from("jms:incomingOrders") .wireTap("jms:orderAudit") .choice()     .when(header("CamelFileName").endsWith(".xml"))         .to("jms:xmlOrders")     .when(header("CamelFileName").regex("^.*(csv|csl)$"))         .to("jms:csvOrders")     .otherwise()         .to("jms:badOrders");java

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