When using Apache Camel bean integration to invoke a method on a Java bean, you can use the @XPath annotation to extract a value from the exchange and bind it to a method parameter.

For example, consider the following route fragment, which invokes the credit method on an AccountService object:

from("queue:payments")
    .beanRef("accountService","credit")
    ...

The credit method uses parameter binding annotations to extract relevant data from the message body and inject it into its parameters, as follows:

public class AccountService {
    ...
    public void credit(
            @XPath("/transaction/transfer/receiver/text()") String name,
            @XPath("/transaction/transfer/amount/text()") String amount
            )
    {
        ...
    }
    ...
}

Table 18, “Predefined Namespaces for @XPath” shows the namespaces that are predefined for XPath. You can use these namespace prefixes in the XPath expression that appears in the @XPath annotation.

You can use the @NamespacePrefix annotation to define custom XML namespaces. Invoke the @NamespacePrefix annotation to initialize the namespaces argument of the @XPath annotation. The namespaces defined by @NamespacePrefix can then be used in the @XPath annotation's expression value.

For example, to associate the prefix, ex, with the custom namespace, http://fusesource.com/examples, invoke the @XPath annotation as follows:

public class AccountService {
  ...
  public void credit(
    @XPath(
      value = "/ex:transaction/ex:transfer/ex:receiver/text()",
      namespaces = @NamespacePrefix(
        prefix = "ex",
        uri = "http://fusesource.com/examples"
      )
    ) String name,
    @XPath(
      value = "/ex:transaction/ex:transfer/ex:amount/text()",
      namespaces = @NamespacePrefix(
        prefix = "ex",
        uri = "http://fusesource.com/examples"
      )
    ) String amount,
  )
  {
    ...
  }
  ...
}