Accessing Message Content

Accessing message headers

Message headers typically contain the most useful message content from the perspective of a router, because headers are often intended to be processed in a router service. To access header data, you must first get the message from the exchange object (for example, using Exchange.getIn()), and then use the Message interface to retrieve the individual headers (for example, using Message.getHeader()).

Example 2.5 shows an example of a custom processor that accesses the value of a header named Authorization. This example uses the ExchangeHelper.getMandatoryHeader() method, which eliminates the need to test for a null header value.

Example 2.5. Accessing an Authorization Header

import org.apache.camel.*;
import org.apache.camel.util.ExchangeHelper;

public class MyProcessor implements Processor {
  public void process(Exchange exchange) {
    String auth = ExchangeHelper.getMandatoryHeader(exchange, "Authorization", String.class);
    // process the authorization string...
    // ...
  }
}

For full details of the Message interface, see Messages.

Accessing the message body

You can also access the message body. For example, to append a string to the end of the In message, you can use the processor shown in Example 2.6.

Example 2.6. Accessing the Message Body

import org.apache.camel.*;
import org.apache.camel.util.ExchangeHelper;

public class MyProcessor implements Processor {
    public void process(Exchange exchange) {
        Message in = exchange.getIn();
        in.setBody(in.getBody(String.class) + " World!");
    }
}

Accessing message attachments

You can access a message's attachments using either the Message.getAttachment() method or the Message.getAttachments() method. See Example 1.2 for more details.