Apache Camel 簡單例子

1、一 demo工程1.下面給出一個從from到to有中間流程process處理的例子public class FileMoveWithCamel public static void main(String args) throws Exception CamelContext context = new DefaultCamelContext(); context.addRoutes(new RouteBuilder() /將d:/temp/inbox/下的文件經(jīng)過process處理移到d:/temp/outbox public void configure() from("file

2、:d:/temp/inbox?noop=true").process(new FileConvertProcessor().to("file:d:/temp/outbox"); ); context.start(); boolean loop =true; while(loop) Thread.sleep(9000); context.stop(); class FileConvertProcessor implements Processor Override public void process(Exchange exchange) throws Excep

3、tion try InputStream body = exchange.getIn().getBody(InputStream.class); BufferedReader in = new BufferedReader(new InputStreamReader(body); StringBuffer strbf = new StringBuffer(""); String str = null; str = in.readLine(); while (str != null) System.out.println(str); strbf.append(str + &q

4、uot; "); str = in.readLine(); exchange.getOut().setHeader(Exchange.FILE_NAME, "converted.txt"); exchange.getOut().setBody(strbf.toString(); catch (IOException e) e.printStackTrace(); 2.下面這個例子是每隔10秒訪問一次http請求，并將訪問到的內(nèi)容寫入文件 /* *1 Create a CamelContext. 2 Optionally, configure components

5、or endpoints. 3 Add whatever routing rules you wish using the DSL and RouteBuilder or using Xml Configuration. 4 Start the context. */public class HttpPollWithQuartzCamel public static void main(String args) throws Exception CamelContext context = new DefaultCamelContext(); context.addRoutes(new Rou

6、teBuilder() public void configure() from("quartz:/report?cron=10 * * * * ?&stateful=true") .to("") .to("file:d:/temp/outbox?fileName=httpindex2.csv"); ); context.start(); boolean loop = true; while (loop) Thread.sleep(25000); context.stop(); 3. 在做系統(tǒng)集成的時候,必不可少的任務就是將數(shù)

7、據(jù)從一種格式轉(zhuǎn)換為另一種格式,再把轉(zhuǎn)換后的格式發(fā)到目標系統(tǒng),在此用實例介紹一下Camel中利用Freemarker做數(shù)據(jù)轉(zhuǎn)換.a :Freemarker的模板如下:<?xml version="1.0" encoding="UTF-8"?><people  xmlns:h="/TR/html4/">    <#escape x as x?xml>    <#list body.peopleLi

8、st as p>    <person id="000001" age="20">        <name>            <family>$p.fname</family>            <given>$

9、p.gname</given>        </name>        <email>$p.email</email>        <link manager="$p.manager" />        <#if p.level = "L1"&g

10、t;        <l1tag>xxx</l1tag>        </#if>    </person>    </#list>    </#escape></people>b :與之對應的Java對象如下:每一個person節(jié)點對應一個ValueObject放在XMLTemplateParamet

11、er的peopleList里面.public class XMLTemplateParameter     private String fileName;        private List<ValueObject> peopleList = new ArrayList<ValueObject>();    public List<ValueObject> getPeopleList()     

12、0;   return peopleList;        public void setPeopleList(List<ValueObject> peopleList)         this.peopleList = peopleList;        public String getFileName()        &#

13、160;return fileName;        public void setFileName(String fileName)         this.fileName = fileName;    public class ValueObject     private String fname;    private String gname;   &

14、#160;private String email;    private String manager;    private String level;c :Route代碼如下:public class CamelFreemarkerRoute extends RouteBuilder     public void configure() throws Exception         from("quartz:/report?

15、cron=10 * * * * ?&stateful=true")        .beanRef("fmBean","prepareFMValues")         .to("freemarker:com/test/camel/freemarker/test.ftl")        .to("file:d:/te

16、mp/outbox?fileName=fm.xml");        d :Route里用到的bean如下:xmlTemplateParameter做為頂級對象放在body里面,Freemarker里取數(shù)據(jù)的body.peopleList就對應于xmlTemplateParameter.peopleListpublic class FmProcessorBean         public void prepareFMValues(Exchange exchan

17、ge)        XMLTemplateParameter xmlTemplateParameter = new XMLTemplateParameter();        ValueObject val = null;        for(int i=0;i<3;i+)            val = new

18、ValueObject();                    val.setFname("Yao");            val.setGname("Yorker" +i);            val.setEmai

19、l("test");            val.setManager("m&an<ager");            val.setLevel("L" + i);            xmlTemplateParameter.getPeopleLi

20、st().add(val);                                    exchange.getIn().setBody(xmlTemplateParameter);        e :Spring的配置文件如下:<beans xml

21、ns="/schema/beans" xmlns:xsi="/2001/XMLSchema-instance" xmlns:camel="/schema/spring" xsi:schemaLocation="/schema/beans /schem

22、a/beans/spring-beans-3.0.xsd /schema/spring /schema/spring/camel-spring.xsd" default-autowire="byName" default-init-method="init">    <bean id="fmBean" class="com.test.camel.freemarker.

23、FmProcessorBean"/>    <camelContext id="testCamelContext" xmlns="/schema/spring">        <package>com.test.camel.freemarker</package>    </camelContext>   &

24、#160;</beans>f :啟動Spring,在D:tempoutbox文件夾下,每隔10秒鐘,會根據(jù)freemarker模板生成一個fm.xml文件.        ApplicationContext ac = new ClassPathXmlApplicationContext("config/camelFreemarker.xml");        while (true)      

25、60;      Thread.sleep(2000);        對本例beanRef("fmBean","prepareFMValues")的解釋:其意思是調(diào)用fmBean的prepareFMValues方法,Camel會負責將message的body綁定到要調(diào)用方法的第一個參數(shù)上面,其中可能做相應的類型轉(zhuǎn)換.(本例中的方法的第一個參數(shù)為Exchange,沒有轉(zhuǎn)換的過程 ),這里給一個如下示例圖解釋這個綁定轉(zhuǎn)換的過程:Camel將Exchange的

26、的input message(exchange.getIn()轉(zhuǎn)換為String,綁定到mtd方法的name參數(shù)上.4下面是一個路由選擇的例子 public class EIP /* * param * return * 方法描述 * author CaiWen * throws Exception * createTime 2014-11-19 * 接口名 */public static void main(String args) throws Exception ConnectionFactory conn = new ActiveMQConnectionFactory("vm

27、:/localhost");CamelContext context = new DefaultCamelContext(); context.addComponent("jms", JmsComponent.jmsComponentAutoAcknowledge(conn); context.addRoutes(new RouteBuilder() public void configure() from("file:d:/temp/inbox?noop=true").to("jms:incomingOrders"); f

28、rom("jms:incomingOrders").choice().when(header("CamelFileName").endsWith(".xml") .to("jms:xmlOrders").when(header("CamelFileName").endsWith(".csv") .to("jms:csvOrders"); from("jms:csvOrders").process(new Processor() Over

29、ride public void process(Exchange arg0) throws Exception System.out.println("Recive xml order :"+arg0.getIn().getHeader("CamelFileName"); InputStream is = arg0.getIn().getBody(InputStream.class); BufferedReader br = new BufferedReader(new InputStreamReader(is); String str = br.re

30、adLine(); while(str!=null) System.out.println(str); str = br.readLine(); ); from("jms:xmlOrders").process(new Processor() Override public void process(Exchange arg0) throws Exception System.out.println("Recive xml order :" + arg0.getIn().getHeader("CamelFileName"); ); )

31、; context.start(); boolean loop =true; while(loop) Thread.sleep(9000); context.stop(); 5. 附加pom.xml <?xml version="1.0" encoding="UTF-8"?><project xmlns="/POM/4.0.0" xmlns:xsi="/2001/XMLSchema-instance" xsi:schema

32、Location="/POM/4.0.0 /maven-v4_0_0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.apache.camel</groupId><artifactId>examples</artifactId><version>2.14.0</version></parent>

33、;<artifactId>camel-example-activemq-tomcat</artifactId><name>Camel : Example : ActiveMQ : Tomcat</name><description>An example using ActiveMQ Broker and Camel with Apache Tomcat</description><packaging>war</packaging><build><plugins><plu

34、gin><groupId>org.codehaus.mojo</groupId><artifactId>tomcat-maven-plugin</artifactId><configuration><server>myTomcat</server><url>$tomcat.url</url><path>/$project.build.finalName</path></configuration></plugin><plugin

35、><groupId>org.codehaus.mojo</groupId><artifactId>exec-maven-plugin</artifactId><configuration><mainClass>org.apache.camel.example.cxf.CamelRouteClient</mainClass><includePluginDependencies>false</includePluginDependencies><systemProperties&

36、gt;<property><key>java.util.logging.config.file</key><value>perties</value></property></systemProperties></configuration></plugin></plugins><!- Name of the generated WAR file -><finalName>camel-example-activemq-tomcat

37、</finalName></build><dependencies><!- camel -><dependency><groupId>org.apache.camel</groupId><artifactId>camel-core</artifactId></dependency><dependency><groupId>org.apache.camel</groupId><artifactId>camel-spring<

38、/artifactId></dependency><dependency><groupId>org.apache.camel</groupId><artifactId>camel-stream</artifactId></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-web</artifactId></dependency>

39、;<!- camel jms and activemq -><dependency><groupId>org.apache.camel</groupId><artifactId>camel-jms</artifactId></dependency><dependency><groupId>org.apache.activemq</groupId><artifactId>activemq-camel</artifactId></dependency

40、><dependency><groupId>org.apache.activemq</groupId><artifactId>activemq-broker</artifactId></dependency><dependency><groupId>org.apache.activemq</groupId><artifactId>activemq-spring</artifactId></dependency><dependency>

41、<groupId>org.apache.activemq</groupId><artifactId>activemq-kahadb-store</artifactId></dependency><dependency><groupId>org.apache.activemq</groupId><artifactId>activemq-client</artifactId></dependency><dependency><groupId>o

42、rg.apache.activemq</groupId><artifactId>activemq-pool</artifactId></dependency><!- xbean is required for ActiveMQ broker configuration in the spring xml file -><dependency><groupId>org.apache.xbean</groupId><artifactId>xbean-spring</artifactId

43、></dependency><dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-quartz</artifactId></dependency><dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-http</artifactId></dependency><depen

44、dency> <groupId>org.apache.camel</groupId> <artifactId>camel-freemarker</artifactId></dependency><!- logging -><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId></dependency><dependency><groupId>or

45、g.slf4j</groupId><artifactId>slf4j-log4j12</artifactId></dependency></dependencies><profiles><profile><id>Tomcat7</id><activation><activeByDefault>true</activeByDefault></activation><properties><tomcat.url>http

46、:/localhost:8080/manager/text</tomcat.url></properties></profile><profile><id>Tomcat6</id><properties><tomcat.url>http:/localhost:8080/manager</tomcat.url></properties></profile></profiles></project>二應用場景及項目應用 Enterpr

47、ise Application Integration 企業(yè)應用集成(EAI)企業(yè)應用集成是必要的，幾乎每家公司都有很多新產(chǎn)品及應用，如何集成這些應用程序是一個問題。來每十年誕生一個新范式，例如客戶端/服務器通信，面向服務的架構(gòu)（SOA）或云計算。此外，不同的接口或協(xié)議和技術的出現(xiàn)。過去數(shù)據(jù)存儲在文件，SQL數(shù)據(jù)庫在今天很通用。有時，還需要NoSQL數(shù)據(jù)庫。同步遠程過程調(diào)用RPC或異步消息是通過如RMI，SOAP的Web服務，REST或JMS進行通信的。很多軟件筒倉還存在。Enterprise Integration Patterns 企業(yè)集成模式(EIP)當然，你可以推倒重來，然后再寫一些意大利面條代碼，讓應用程序協(xié)同工作。不幸的是，你的管理者不會喜歡這個缺少長遠眼光的解決方案。企業(yè)集成模式（）幫助碎片的問題，并使用標準化的方法來集成應用程序。使用相同的概念路由消息來改造。因此，每次有問題時重新發(fā)明輪子不是個好主意。集成的替代方案解決方案1 ：自定義解決方案實現(xiàn)一個單獨的解決方案，適用于您的問題還沒有分離切成碎片。此工程可能是最快的替代的小型用例。你必須自己編寫所有。維護成本可能會高