camel系列-拦截器

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概念

Camel 中的拦截器功能支持在路由时拦截Exchange。

拦截器类型

  • intercept：拦截路由期间发生的每个处理步骤
  • interceptFrom：仅拦截传入的步骤
  • interceptSendToEndpoint：仅在 Exchange 即将发送到给定端点时才拦截。

示例

intercept

DSL 示例

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<route>
  <from uri="timer:xml?period=5s"/>
  <intercept>
    <to uri="log:hello"/>
  </intercept>
  <log message="I am XML"/>
  <log message="I am YAML"/>
</route>

运行日志

每个步骤都会处理拦截

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13:56:05.423 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  hello - Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]
13:56:05.424 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am XML
13:56:05.424 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  hello - Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]
13:56:05.424 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am YAML

interceptFrom

DSL 示例

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<route>
  <from uri="timer:xml?period=5s"/>
  <interceptFrom>
    <to uri="log:hello"/>
  </interceptFrom>
  <log message="I am XML"/>
  <log message="I am YAML"/>
</route>

运行日志

仅拦截传入的步骤

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14:11:09.483 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  hello - Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]
14:11:09.483 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am XML
14:11:09.484 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am YAML

interceptSendToEndpoint

DSL 示例

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<route>
    <from uri="timer:xml?period=5s"/>
    <interceptSendToEndpoint>
        <to uri="log:hello"/>
    </interceptSendToEndpoint>
    <log message="I am XML"/>
    <log message="I am YAML"/>
    <to uri="log:result" />
</route>

运行日志

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14:13:53.571 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am XML
14:13:53.572 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am YAML
14:13:53.572 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  hello - Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]
14:13:53.573 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  result - Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]14:11:09.483 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  hello - Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]

作用域

分为全局和局部路由范围，上面例子均为路由范围

全局拦截配置

DSL 配置

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<routeConfiguration>
    <interceptFrom uri="*">
        <log message="Message intercepted from ${header.CamelInterceptedEndpoint}"/>
    </interceptFrom>
</routeConfiguration>

<route>
    <from uri="timer:xml?period=5s"/>
    <log message="I am XML"/>
    <log message="I am YAML"/>
    <to uri="log:result" />
</route>

运行日志

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14:25:42.571 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - Message intercepted from timer://xml?period=5s
14:25:42.571 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am XML
14:25:42.572 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  route1 - I am YAML
14:25:42.572 [Camel (MyJavaLoader) thread #1 - timer://xml] INFO  result - Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]

拦截条件

使用 when 添加一个谓语条件

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<intercept>
  <when>
    <simple>${in.body} contains 'Hello'</simple>
  </when>
  <to uri="mock:intercepted"/>
</intercept>

拦截后停止路由

使用 stop 方法，即拦截后不再执行路由流程

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<intercept>
    <when>
      <simple>${body} contains 'Hello'</simple>
      <to uri="log:test"/>
      <stop/> <!-- stop continue routing -->
    </when>
</intercept>

特定端点拦截跳过绕道

对特定端点进行拦截并跳过

以下 DSL 中,原 kafka 端点将不会被送达，而是被拦截绕道到 mock:kafka

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<camelContext>

  <interceptSendToEndpoint uri="kafka*" skipSendToOriginalEndpoint="true">
    <to uri="mock:kafka"/>
  </intercept>

  <route>
    <from uri="jms:queue:order"/>
    <to uri="bean:validateOrder"/>
    <to uri="bean:processOrder"/>
    <to uri="kafka:order"/>
  </route>

</camelContext>

参考