camel系列-camel-main

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概述

camel-main 提供了一个 Main 扩展类，用于 camel 应用独立运行

加载 Spring DSL

程序入口

  1. 使用 org.apache.camel.spring.Main 类实例化一个对象
  2. 使用 setApplicationContextUri 方法指定待加载的 Spring XML 文件
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import org.apache.camel.spring.Main;

/**
 * A main class to run the example from your editor.
 */
public final class CamelConsoleMain {

    private CamelConsoleMain() {
    }

    public static void main(String[] args) throws Exception {
        // Main makes it easier to run a Spring application
        Main main = new Main();
        // configure the location of the Spring XML file
        main.setApplicationContextUri("META-INF/spring/camel-context.xml");
        // run and block until Camel is stopped (or JVM terminated)
        main.run();
    }
}

spring xml 配置

  1. 在配置文件中声明 camelContext 节点
  2. 在 camelContext 节点中声明 route 节点
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<beans xmlns="http://www.springframework.org/schema/beans"
       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.xsd
       http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd">

  <!-- camelContext is the Camel runtime, where we can host Camel routes -->
  <camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
      <!-- read input from the console using the stream component -->
      <from uri="stream:in?promptMessage=Enter something: "/>
      <!-- transform the input to upper case using the simple language -->
      <!-- you can also use other languages such as groovy, ognl, mvel, javascript etc. -->
      <transform>
        <simple>${body.toUpperCase()}</simple>
      </transform>
      <!-- and then print to the console -->
      <to uri="stream:out"/>
    </route>
  </camelContext>

</beans>

运行效果

这是一个命令行程序，将输入的字母转义成大写字母

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Enter something: hello,world
HELLO,WORLD

Bean 装配

CamelMain 支持 Bean 装配，这一点类似 Spring

  1. 使用addConfigurationClass添加要装配的配置类
  2. 使用BindToRegistry注解声明要装配的类实例
  3. 使用PropertyInject注解声明要注入的 properties 配置字段
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public static void main(String[] args) throws Exception {
    // use Camels Main class
    Main main = new Main();
    main.configure().addConfigurationClass(MyConfiguration.class);
}

public class MyConfiguration {

    @BindToRegistry
    public MyBean myBean(@PropertyInject("hi") String hi, @PropertyInject("bye") String bye) {
        // this will create an instance of this bean with the name of the method (eg myBean)
        return new MyBean(hi, bye);
    }
}

public class MyBean {

    private String hi;
    private String bye;

    public MyBean(String hi, String bye) {
        this.hi = hi;
        this.bye = bye;
    }

    public String hello() {
        return hi + " how are you?";
    }

    public String bye() {
        return bye + " World";
    }
}

application.properties 清单

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# application properties
hi = Hello
bye = Bye

路由资源加载

全局加载

RoutesIncludePattern 类似于全局加载，不需要指定加载目录

camel.main.routesIncludePattern：用于从注册表或通过类路径扫描收集的包容性过滤 RouteBuilder 类。排他过滤优先于包含过滤。该模式使用 Ant-path 样式模式。可以用逗号分隔多个模式。可以用逗号分隔多个模式。例如，要包含以 Foo 开头的所有类，请使用：**/Foo 要包含来自特定包的所有路由，请使用：com/mycompany/foo/* 要包含来自特定包及其子包的所有路由，请使用双通配符：com/mycompany/foo/** 要包含来自两个特定包的所有路由，请使用：com/mycompany/foo/,com/mycompany/stuff/

如下代码清单

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public static void main(String[] args) throws Exception {
    Main main = new Main();
    main.configure().addConfigurationClass(MyConfiguration.class);
    main.configure().withRoutesIncludePattern("routes/*.xml");
    main.run(args);
}

或者在 application.properties 中配置

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camel.main.routes-include-pattern = routes/*.xml

路由重载

Camel 中的路由重载功能能够监视目录文件夹中的文件更改，然后自动触发重载 Camel 应用程序中正在运行的路由。

此功能旨在用于开发目的，而不是用于生产用途。

routesReloadEnabled 用于启用自动路由重新加载。如果启用，那么 Camel 将监视给定重新加载目录中的文件更改，并在文件更改时触发重新加载路由。
routesReloadDirectory 用于扫描路由更改的目录。Camel 无法扫描类路径，因此必须将其配置为文件目录。使用 Maven 作为构建工具进行开发，您可以将目录配置为 src/main/resources 以扫描 XML 或 YAML 文件中的 Camel 路由。
routesReloadPattern 用于对来自目录的路由进行包容性过滤。典型用于指定接受 XML 或 YAML 文件中的路由。默认模式为 .yaml,.xml 可以指定多个模式，以逗号分隔。

在应用中指定参数

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public static void main(String[] args) throws Exception {
    // use Camels Main class
    Main main = new Main();
    // lets use a configuration class (you can specify multiple classes)
    // (properties are automatic loaded from application.properties)
    main.configure().addConfigurationClass(MyConfiguration.class);
    // and add all the XML routes
    main.configure().withRoutesIncludePattern("routes/*.xml");
    // turn on reloading routes on code-changes
    main.configure().withRoutesReloadEnabled(true);
    main.configure().withRoutesReloadDirectory("src/main/resources");
    main.configure().withRoutesReloadPattern("routes/*.xml");

    // now keep the application running until the JVM is terminated (ctrl + c or sigterm)
    main.run(args);
}

application.properties 配置清单

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# turn on route reloading on file changes
camel.main.routes-reload-enabled = true
# the base directory to watch
camel.main.routes-reload-directory = src/main/resources
# pattern(s) for files to watch
camel.main.routes-reload-pattern = routes/*.xml

XML && YAML DSL 加载

XML DSL

application.properties 配置清单

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# load XML routes
camel.main.routes-include-pattern = routes/*.xml

# turn on route reloading on file changes
camel.main.routes-reload-enabled = true
# the base directory to watch
camel.main.routes-reload-directory = src/main/resources/
# pattern(s) for files to watch
camel.main.routes-reload-pattern = routes/*.xml

DSL 配置

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<routes id="camel" xmlns="http://camel.apache.org/schema/spring">
  <route id="foo3">
    <from uri="quartz:foo?cron={{myCron}}"/>
    <bean ref="myBean" method="hello"/>
    <log message="${body}"/>
    <bean ref="myBean" method="bye"/>
    <log message="${body}"/>
  </route>
</routes>

YAML DSL

application.properties 配置清单

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# turn on route reloading on file changes
camel.main.routes-reload-enabled = true
# the base directory to watch
camel.main.routes-reload-directory = src/main/resources
# pattern(s) for files to watch
camel.main.routes-reload-pattern = routes/*.yaml
# on reload should all existing routes be removed first
camel.main.routes-reload-remove-all-routes = true

DSL 配置

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- route:
    id: "foo"
    from: "quartz:foo?cron={{myCron}}"
    steps:
      - to: "bean:myBean?method=hello"
      - log: "${body}"
      - to: "bean:myBean?method=bye"
      - log: "${body}"