Chapter 122. StAX

StAX Component
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Available as of Camel 2.9

The StAX component allows messages to be process through a SAX ContentHandler. Another feature of this component is to allow to iterate over JAXB records using StAX, for example using the Splitter EIP.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-stax</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-stax</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

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URI format
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stax:content-handler-class

stax:content-handler-class

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example:

stax:org.superbiz.FooContentHandler

stax:org.superbiz.FooContentHandler

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From Camel 2.11.1 onwards you can lookup a org.xml.sax.ContentHandler bean from the Registry using the # syntax as shown:

stax:#myHandler

stax:#myHandler

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Usage of a content handler as StAX parser
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The message body after the handling is the handler itself.

Here an example:

from("file:target/in")
  .to("stax:org.superbiz.handler.CountingHandler") 
  // CountingHandler implements org.xml.sax.ContentHandler or extends org.xml.sax.helpers.DefaultHandler
  .process(new Processor() {
    @Override
    public void process(Exchange exchange) throws Exception {
        CountingHandler handler = exchange.getIn().getBody(CountingHandler.class);
        // do some great work with the handler
    }
  });

from("file:target/in")
  .to("stax:org.superbiz.handler.CountingHandler") 
  // CountingHandler implements org.xml.sax.ContentHandler or extends org.xml.sax.helpers.DefaultHandler
  .process(new Processor() {
    @Override
    public void process(Exchange exchange) throws Exception {
        CountingHandler handler = exchange.getIn().getBody(CountingHandler.class);
        // do some great work with the handler
    }
  });

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Iterate over a collection using JAXB and StAX
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First we suppose you have JAXB objects.

For instance a list of records in a wrapper object:

import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "records")
public class Records {
    @XmlElement(required = true)
    protected List<Record> record;

    public List<Record> getRecord() {
        if (record == null) {
            record = new ArrayList<Record>();
        }
        return record;
    }
}

import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "records")
public class Records {
    @XmlElement(required = true)
    protected List<Record> record;

    public List<Record> getRecord() {
        if (record == null) {
            record = new ArrayList<Record>();
        }
        return record;
    }
}

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and

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "record", propOrder = { "key", "value" })
public class Record {
    @XmlAttribute(required = true)
    protected String key;

    @XmlAttribute(required = true)
    protected String value;

    public String getKey() {
        return key;
    }

    public void setKey(String key) {
        this.key = key;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "record", propOrder = { "key", "value" })
public class Record {
    @XmlAttribute(required = true)
    protected String key;

    @XmlAttribute(required = true)
    protected String value;

    public String getKey() {
        return key;
    }

    public void setKey(String key) {
        this.key = key;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

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Then you get a XML file to process:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<records>
  <record value="v0" key="0"/>
  <record value="v1" key="1"/>
  <record value="v2" key="2"/>
  <record value="v3" key="3"/>
  <record value="v4" key="4"/>
  <record value="v5" key="5"/>
</record>

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<records>
  <record value="v0" key="0"/>
  <record value="v1" key="1"/>
  <record value="v2" key="2"/>
  <record value="v3" key="3"/>
  <record value="v4" key="4"/>
  <record value="v5" key="5"/>
</record>

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The StAX component provides an StAXBuilder which can be used when iterating XML elements with the Camel Splitter

from("file:target/in")
    .split(stax(Record.class)).streaming()
        .to("mock:records");

from("file:target/in")
    .split(stax(Record.class)).streaming()
        .to("mock:records");

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Where stax is a static method on org.apache.camel.component.stax.StAXBuilder which you can static import in the Java code. The stax builder is by default namespace aware on the XMLReader it uses. From Camel 2.11.1 onwards you can turn this off by setting the boolean parameter to false, as shown below:

from("file:target/in")
    .split(stax(Record.class, false)).streaming()
        .to("mock:records");

from("file:target/in")
    .split(stax(Record.class, false)).streaming()
        .to("mock:records");

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The previous example with XML DSL
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The example above could be implemented as follows in XML DSL

<!-- use STaXBuilder to create the expression we want to use in the route below for splitting the XML file -->
<!-- notice we use the factory-method to define the stax method, and to pass in the parameter as a constructor-arg -->
<bean id="staxRecord" class="org.apache.camel.component.stax.StAXBuilder" factory-method="stax">
  <!-- FQN class name of the POJO with the JAXB annotations -->
  <constructor-arg index="0" value="org.apache.camel.component.stax.model.Record"/>
</bean>

<camelContext xmlns="http://camel.apache.org/schema/spring">
  <route>
    <!-- pickup XML files -->
    <from uri="file:target/in"/>
    <split streaming="true">
      <!-- split the file using StAX (ref to bean above) -->
      <!-- and use streaming mode in the splitter -->
      <ref>staxRecord</ref>
      <!-- and send each splitted to a mock endpoint, which will be a Record POJO instance -->
      <to uri="mock:records"/>
    </split>
  </route>
</camelContext>

<!-- use STaXBuilder to create the expression we want to use in the route below for splitting the XML file -->
<!-- notice we use the factory-method to define the stax method, and to pass in the parameter as a constructor-arg -->
<bean id="staxRecord" class="org.apache.camel.component.stax.StAXBuilder" factory-method="stax">
  <!-- FQN class name of the POJO with the JAXB annotations -->
  <constructor-arg index="0" value="org.apache.camel.component.stax.model.Record"/>
</bean>

<camelContext xmlns="http://camel.apache.org/schema/spring">
  <route>
    <!-- pickup XML files -->
    <from uri="file:target/in"/>
    <split streaming="true">
      <!-- split the file using StAX (ref to bean above) -->
      <!-- and use streaming mode in the splitter -->
      <ref>staxRecord</ref>
      <!-- and send each splitted to a mock endpoint, which will be a Record POJO instance -->
      <to uri="mock:records"/>
    </split>
  </route>
</camelContext>

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이 콘텐츠는 선택한 언어로 제공되지 않습니다.

StAX Component
링크 복사

URI format
링크 복사

Usage of a content handler as StAX parser
링크 복사

Iterate over a collection using JAXB and StAX
링크 복사

The previous example with XML DSL
링크 복사

자세한 정보

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이 콘텐츠는 선택한 언어로 제공되지 않습니다.

Chapter 122. StAX

StAX Component링크 복사링크가 클립보드에 복사되었습니다!

URI format링크 복사링크가 클립보드에 복사되었습니다!

Usage of a content handler as StAX parser링크 복사링크가 클립보드에 복사되었습니다!

Iterate over a collection using JAXB and StAX링크 복사링크가 클립보드에 복사되었습니다!

The previous example with XML DSL링크 복사링크가 클립보드에 복사되었습니다!

자세한 정보

평가판, 구매 및 판매

커뮤니티

Red Hat 문서 정보

보다 포괄적 수용을 위한 오픈 소스 용어 교체

Red Hat 소개

Theme

Red Hat legal and privacy links

Red Hat legal and privacy links

StAX Component
링크 복사

URI format
링크 복사

Usage of a content handler as StAX parser
링크 복사

Iterate over a collection using JAXB and StAX
링크 복사

The previous example with XML DSL
링크 복사