我有一个场景，我分割xml并将它们发送到activemq，然后想要记录标题orderid和region。为了获得区域，我使用的是java方法：
import org.apache.camel.language.NamespacePrefix;
import org.apache.camel.language.XPath;
/**
* This class contains business logic that determines the region for a country. It is used by the Camel route in this example.
*/
public class RegionSupport {
public static final String AMER = "AMER";
public static final String APAC = "APAC";
public static final String EMEA = "EMEA";
/**
* Get the region code that corresponds to the given country code.
*
* This method can be used as a plain Java method. However, when it is used inside a Camel route, the @XPath annotation will
* evaluate the XPath expression and use the result as the method parameter. In this case, it will fetch the country code
* from the order XML message. So, the method will determine the region code for the country that is in the XML message.
*
* @param country the country code
* @return the region code
*/
public String getRegion(@XPath(value = "/order:order/order:customer/order:country",
String country) {
if (country.equals("AU")) {
return APAC;
} else if (country.equals("US")) {
return AMER;
} else {
return EMEA;
}
}
}
XML INPUT：
因此，根据xml以下我应该在第一次交换中将标题记录为id = 2012_0001 Region = APAC
<?xml version="1.0" encoding="UTF-8"?>
<orders>
<order id="2012_0001">
<customer id="A0001">
<name>Antwerp Zoo</name>
<city>Antwerp</city>
<country>AU</country>
</customer>
<date>2012-03-01</date>
<orderlines>
<orderline>
<article id="A0001">
<description>Aardvark</description>
</article>
<quantity>1</quantity>
</orderline>
<orderline>
<article id="A0011">
<description>Alpaca</description>
</article>
<quantity>10</quantity>
</orderline>
</orderlines>
</order>
<order id="2012_0002">
<customer id="B0002">
<name>Bristol Zoo Gardens</name>
<city>Bristol</city>
<country>UK</country>
</customer>
<date>2012-03-02</date>
<orderlines>
<orderline>
<article id="B0002">
<description>Badger</description>
</article>
<quantity>2</quantity>
</orderline>
<orderline>
<article id="B0202">
<description>Bee</description>
</article>
<quantity>200</quantity>
</orderline>
</orderlines>
</order>
</orders>
XSLT：
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="no" indent="yes"/>
<xsl:template match="/">
<xsl:element name="orders">
<xsl:element name="order">
<xsl:copy-of select="/*[local-name()='order']/*"
/>
</xsl:element>
</xsl:element>
</xsl:template>
</xsl:stylesheet>
我的骆驼路线：
<route id="Splitter_Route">
<from id="_from2" uri="direct:Splitter"/>
<log id="_log6" message="Recieved file to split : ${file:name}"/>
<split id="_split1">
<xpath>/orders/order</xpath>
<log id="_log3" message="split data : ${body}"/>
<to id="_to1" uri="xslt:file:F:\jboss_workspace\ZooPattern\data\order.xsl"/>
<log id="_log2" message="After XSLT : ${body} "/>
<to id="_to2" uri="activemq:queue:zoodata"/>
<log id="_log7" message="${body}"/>
<setHeader headerName="orderId" id="_setHeader1">
<xpath resultType="java.lang.String">/order:order/@id</xpath>
</setHeader>
<setHeader headerName="region" id="_setHeader2">
<method bean="MyRegionSupport" method="getRegion"/>
</setHeader>
<log id="_log9" message="[splitter] Shipping order ${header.orderId}"/>
</split>
</route>
ERROR_Output：
所以我得到正确的输出直到activemq。在Activemq logid7没有在xml中给出订单ID之后。之后它会给出如下错误。 请让我知道我哪里出错了。
thread #2 - file://zoodata/in] Splitter_Route INFO split data : <order id="2012_0001">
<customer id="A0001">
<name>Antwerp Zoo</name>
<city>Antwerp</city>
<country>BE</country>
</customer>
<date>2012-03-01</date>
<orderlines>
<orderline>
<article id="A0001">
<description>Aardvark</description>
</article>
<quantity>1</quantity>
</orderline>
<orderline>
<article id="A0011">
<description>Alpaca</description>
</article>
<quantity>10</quantity>
</orderline>
</orderlines>
</order>
[ thread #2 - file://zoodata/in] Splitter_Route INFO After XSLT : <?xml version="1.0" encoding="UTF-8"?><orders>
<order>
<customer id="A0001">
<name>Antwerp Zoo</name>
<city>Antwerp</city>
<country>BE</country>
</customer>
<date>2012-03-01</date>
<orderlines>
<orderline>
<article id="A0001">
<description>Aardvark</description>
</article>
<quantity>1</quantity>
</orderline>
<orderline>
<article id="A0011">
<description>Alpaca</description>
</article>
<quantity>10</quantity>
</orderline>
</orderlines>
</order>
</orders>
[ thread #2 - file://zoodata/in] Splitter_Route INFO <?xml version="1.0" encoding="UTF-8"?><orders>
<order>
<customer id="A0001">
<name>Antwerp Zoo</name>
<city>Antwerp</city>
<country>BE</country>
</customer>
<date>2012-03-01</date>
<orderlines>
<orderline>
<article id="A0001">
<description>Aardvark</description>
</article>
<quantity>1</quantity>
</orderline>
<orderline>
<article id="A0011">
<description>Alpaca</description>
</article>
<quantity>10</quantity>
</orderline>
</orderlines>
</order>
</orders>
[ thread #2 - file://zoodata/in] DefaultErrorHandler ERROR Failed delivery for (MessageId: ID-LAPTOP-OO1BQC0T-63587-1514125730408-0-37 on ExchangeId: ID-LAPTOP-OO1BQC0T-63587-1514125730408-0-38). Exhausted after delivery attempt: 1 caught: org.apache.camel.builder.xml.InvalidXPathExpression: Invalid xpath: /order:order/@id. Reason: javax.xml.xpath.XPathExpressionException: com.sun.org.apache.xpath.internal.domapi.XPathStylesheetDOM3Exception: Prefix must resolve to a namespace: order
Message History
---------------------------------------------------------------------------------------------------------------------------------------
RouteId ProcessorId Processor Elapsed (ms)
[_route1 ] [_route1 ] [file://zoodata/in ] [ 82]
[Splitter_Route ] [_log3 ] [log ] [ 0]
[Splitter_Route ] [_to1 ] [xslt:file:F:\jboss_workspace\ZooPattern\data\order.xsl ] [ 15]
[Splitter_Route ] [_log2 ] [log ] [ 0]
[Splitter_Route ] [_to2 ] [activemq:queue:zoodata ] [ 67]
[Splitter_Route ] [_log7 ] [log ] [ 0]
[Splitter_Route ] [_setHeader1 ] [setHeader[orderId] ] [ 0]
Stacktrace
---------------------------------------------------------------------------------------------------------------------------------------
org.apache.camel.builder.xml.InvalidXPathExpression: Invalid xpath: /order:order/@id. Reason: javax.xml.xpath.XPathExpressionException: com.sun.org.apache.xpath.internal.domapi.XPathStylesheetDOM3Exception: Prefix must resolve to a namespace: order
at org.apache.camel.builder.xml.XPathBuilder.evaluateAs(XPathBuilder.java:769)
at org.apache.camel.builder.xml.XPathBuilder.evaluate(XPathBuilder.java:750)
at org.apache.camel.builder.xml.XPathBuilder.evaluate(XPathBuilder.java:165)
at org.apache.camel.processor.SetHeaderProcessor.process(SetHeaderProcessor.java:52)
答案 0 :(得分：1)
错误说
Prefix must resolve to a namespace: order
这意味着您必须使用order设置您在XML文件中执行的<camelContext>命名空间。在那里你将它添加为属性
<camelContext .... xmlns:order="http://bla bla">
其中值是命名空间的唯一uri，通常是某个web url。
但是，您的XML输入不使用命名空间，因此您的问题是setHeader中的xpath正在使用它。但是你应该删除它并使用匿名xpath，这应该是一个简单的修复
<xpath resultType="java.lang.String">/order:order/@id</xpath>
应该是
<xpath resultType="java.lang.String">/order/@id</xpath>
例如带冒号的order:是名称空间前缀，因此应删除它。