File Component

The File component provides access to file systems, allowing files to be processed by any other Camel Components or messages from other components to be saved to disk.

URI format

file:directoryName[?options]

or

file://directoryName[?options]

Where directoryName represents the underlying file directory.

You can append query options to the URI in the following format, ?option=value&option=value&...

URI Options

Common

Consumer

Default behavior for file consumer

• By default the file is locked for the duration of the processing.

• After the route has completed, files are moved into the .camel subdirectory, so that they appear to be deleted.

• The File Consumer will always skip any file whose name starts with a dot, such as ., .camel, .m2 or .groovy.

• Only files (not directories) are matched for valid filename, if options such as: include or exclude are used.

Producer

Default behavior for file producer

• By default it will override any existing file, if one exist with the same name.

Move and Delete operations

Any move or delete operations is executed after (post command) the routing has completed; so during processing of the Exchange the file is still located in the inbox folder.

Lets illustrate this with an example:

    from("file://inbox?move=.done").to("bean:handleOrder");

When a file is dropped in the inbox folder, the file consumer notices this and creates a new FileExchange that is routed to the handleOrder bean. The bean then processes the File object. At this point in time the file is still located in the inbox folder. After the bean completes, and thus the route is completed, the file consumer will perform the move operation and move the file to the .done sub-folder.

The move and preMove options should be a directory name, which can be either relative or absolute. If relative, the directory is created as a sub-folder from within the folder where the file was consumed.

By default, Camel will move consumed files to the .camel sub-folder relative to the directory where the file was consumed.

If you want to delete the file after processing, the route should be:

    from("file://inobox?delete=true").to("bean:handleOrder");

We have introduced a pre move operation to move files before they are processed. This allows you to mark which files have been scanned as they are moved to this sub folder before being processed.

    from("file://inbox?preMove=inprogress").to("bean:handleOrder");

You can combine the pre move and the regular move:

    from("file://inbox?preMove=inprogress&move=.done").to("bean:handleOrder");

So in this situation, the file is in the inprogress folder when being processed and after it's processed, it's moved to the .done folder.

Fine grained control over Move and PreMove option

The move and preMove option is Expression-based, so we have the full power of the File Language to do advanced configuration of the directory and name pattern.
Camel will, in fact, internally convert the directory name you enter into a File Language expression. So when we enter move=.done Camel will convert this into: ${file:parent}/.done/${file:onlyname}. This is only done if Camel detects that you have not provided a ${ } in the option value yourself. So when you enter a ${ } Camel will not convert it and thus you have the full power.

So if we want to move the file into a backup folder with today's date as the pattern, we can do:

move=backup/${date:now:yyyyMMdd}/${file:name}

About moveFailed

The moveFailed option allows you to move files that could not be processed succesfully to another location such as a error folder of your choice. For example to move the files in an error folder with a timestamp you can use moveFailed=/error/${file:name.noext}-${date:now:yyyyMMddHHmmssSSS}.${file:ext}.

See more examples at File Language

Message Headers

The following headers are supported by this component:

File producer only

File consumer only

Batch Consumer

This component implements the Batch Consumer.

Exchange Properties, file consumer only

As the file consumer is BatchConsumer it supports batching the files it polls. By batching it means that Camel will add some properties to the Exchange so you know the number of files polled the current index in that order.

This allows you for instance to know how many files exists in this batch and for instance let the Aggregator2 aggregate this number of files.

Using charset

Available as of Camel 2.9.3
The charset option allows to configure an encoding of the files on both the consumer and producer endpoints. For example if you read utf-8 files, and want to convert the files to iso-8859-1, you can do:

from("file:inbox?charset=utf-8")
  .to("file:outbox?charset=iso-8859-1")

You can also use the convertBodyTo in the route. In the example below we have still input files in utf-8 format, but we want to convert the file content to a byte array in iso-8859-1 format. And then let a bean process the data. Before writing the content to the outbox folder using the current charset.

from("file:inbox?charset=utf-8")
  .convertBodyTo(byte[].class, "iso-8859-1")
  .to("bean:myBean")
  .to("file:outbox");

If you omit the charset on the consumer endpoint, then Camel does not know the charset of the file, and would by default use "UTF-8". However you can configure a JVM system property to override and use a different default encoding with the key org.apache.camel.default.charset.

In the example below this could be a problem if the files is not in UTF-8 encoding, which would be the default encoding for read the files.
In this example when writing the files, the content has already been converted to a byte array, and thus would write the content directly as is (without any further encodings).

from("file:inbox")
  .convertBodyTo(byte[].class, "iso-8859-1")
  .to("bean:myBean")
  .to("file:outbox");

You can also override and control the encoding dynamic when writing files, by setting a property on the exchange with the key Exchange.CHARSET_NAME. For example in the route below we set the property with a value from a message header.

from("file:inbox")
  .convertBodyTo(byte[].class, "iso-8859-1")
  .to("bean:myBean")
  .setProperty(Exchange.CHARSET_NAME, header("someCharsetHeader"))
  .to("file:outbox");

We suggest to keep things simpler, so if you pickup files with the same encoding, and want to write the files in a specific encoding, then favor to use the charset option on the endpoints.

Notice that if you have explicit configured a charset option on the endpoint, then that configuration is used, regardless of the Exchange.CHARSET_NAME property.

If you have some issues then you can enable DEBUG logging on org.apache.camel.component.file, and Camel logs when it reads/write a file using a specific charset.
For example the route below will log the following:

from("file:inbox?charset=utf-8")
  .to("file:outbox?charset=iso-8859-1")

And the logs:

DEBUG GenericFileConverter           - Read file /Users/davsclaus/workspace/camel/camel-core/target/charset/input/input.txt with charset utf-8
DEBUG FileOperations                 - Using Reader to write file: target/charset/output.txt with charset: iso-8859-1

Common gotchas with folder and filenames

When Camel is producing files (writing files) there are a few gotchas affecting how to set a filename of your choice. By default, Camel will use the message ID as the filename, and since the message ID is normally a unique generated ID, you will end up with filenames such as: ID-MACHINENAME-2443-1211718892437-1-0. If such a filename is not desired, then you must provide a filename in the CamelFileName message header. The constant, Exchange.FILE_NAME, can also be used.

The sample code below produces files using the message ID as the filename:

from("direct:report").to("file:target/reports");

To use report.txt as the filename you have to do:

from("direct:report").setHeader(Exchange.FILE_NAME, constant("report.txt")).to( "file:target/reports");

... the same as above, but with CamelFileName:

from("direct:report").setHeader("CamelFileName", constant("report.txt")).to( "file:target/reports");

And a syntax where we set the filename on the endpoint with the fileName URI option.

from("direct:report").to("file:target/reports/?fileName=report.txt");

Filename Expression

Filename can be set either using the expression option or as a string-based File Language expression in the CamelFileName header. See the File Language for syntax and samples.

Consuming files from folders where others drop files directly

Beware if you consume files from a folder where other applications write files directly. Take a look at the different readLock options to see what suits your use cases. The best approach is however to write to another folder and after the write move the file in the drop folder. However if you write files directly to the drop folder then the option changed could better detect whether a file is currently being written/copied as it uses a file changed algorithm to see whether the file size / modification changes over a period of time. The other read lock options rely on Java File API that sadly is not always very good at detecting this. You may also want to look at the doneFileName option, which uses a marker file (done) to signal when a file is done and ready to be consumed.

Using done files

Available as of Camel 2.6

See also section writing done files below.

If you want only to consume files when a done file exists, then you can use the doneFileName option on the endpoint.

from("file:bar?doneFileName=done");

Will only consume files from the bar folder, if a file name done exists in the same directory as the target files. Camel will automatically delete the done file when it's done consuming the files. From Camel 2.9.3 onwards Camel will not automatic delete the done file if noop=true is configured.

However its more common to have one done file per target file. This means there is a 1:1 correlation. To do this you must use dynamic placeholders in the doneFileName option. Currently Camel supports the following two dynamic tokens: file:name and file:name.noext which must be enclosed in ${ }. The consumer only supports the static part of the done file name as either prefix or suffix (not both).

from("file:bar?doneFileName=${file:name}.done");

In this example only files will be polled if there exists a done file with the name file name.done. For example

• hello.txt - is the file to be consumed

• hello.txt.done - is the associated done file

You can also use a prefix for the done file, such as:

from("file:bar?doneFileName=ready-${file:name}");

• hello.txt - is the file to be consumed

• ready-hello.txt - is the associated done file

Writing done files

Available as of Camel 2.6

After you have written af file you may want to write an additional done file as a kinda of marker, to indicate to others that the file is finished and has been written. To do that you can use the doneFileName option on the file producer endpoint.

.to("file:bar?doneFileName=done");

Will simply create a file named done in the same directory as the target file.

However its more common to have one done file per target file. This means there is a 1:1 correlation. To do this you must use dynamic placeholders in the doneFileName option. Currently Camel supports the following two dynamic tokens: file:name and file:name.noext which must be enclosed in ${ }.

.to("file:bar?doneFileName=done-${file:name}");

Will for example create a file named done-foo.txt if the target file was foo.txt in the same directory as the target file.

.to("file:bar?doneFileName=${file:name}.done");

Will for example create a file named foo.txt.done if the target file was foo.txt in the same directory as the target file.

.to("file:bar?doneFileName=${file:name.noext}.done");

Will for example create a file named foo.done if the target file was foo.txt in the same directory as the target file.

Samples

Read from a directory and write to another directory

from("file://inputdir/?delete=true").to("file://outputdir")

Listen on a directory and create a message for each file dropped there. Copy the contents to the outputdir and delete the file in the inputdir.

Reading recursively from a directory and writing to another

from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")

Listen on a directory and create a message for each file dropped there. Copy the contents to the outputdir and delete the file in the inputdir. Will scan recursively into sub-directories. Will lay out the files in the same directory structure in the outputdir as the inputdir, including any sub-directories.

inputdir/foo.txt
inputdir/sub/bar.txt

Will result in the following output layout:

outputdir/foo.txt
outputdir/sub/bar.txt

Using flatten

If you want to store the files in the outputdir directory in the same directory, disregarding the source directory layout (e.g. to flatten out the path), you just add the flatten=true option on the file producer side:

from("file://inputdir/?recursive=true&delete=true").to("file://outputdir?flatten=true")

Will result in the following output layout:

outputdir/foo.txt
outputdir/bar.txt

Reading from a directory and the default move operation

Camel will by default move any processed file into a .camel subdirectory in the directory the file was consumed from.

from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")

Affects the layout as follows:
before

inputdir/foo.txt
inputdir/sub/bar.txt

after

inputdir/.camel/foo.txt
inputdir/sub/.camel/bar.txt
outputdir/foo.txt
outputdir/sub/bar.txt

Read from a directory and process the message in java

from("file://inputdir/").process(new Processor() {
  public void process(Exchange exchange) throws Exception {
    Object body = exchange.getIn().getBody();
    // do some business logic with the input body
  }
});

The body will be a File object that points to the file that was just dropped into the inputdir directory.

Writing to files

Camel is of course also able to write files, i.e. produce files. In the sample below we receive some reports on the SEDA queue that we process before they are written to a directory.

    public void testToFile() throws Exception {
        MockEndpoint mock = getMockEndpoint("mock:result");
        mock.expectedMessageCount(1);
        mock.expectedFileExists("target/test-reports/report.txt");

        template.sendBody("direct:reports", "This is a great report");

        assertMockEndpointsSatisfied();
    }

    protected JndiRegistry createRegistry() throws Exception {
        // bind our processor in the registry with the given id
        JndiRegistry reg = super.createRegistry();
        reg.bind("processReport", new ProcessReport());
        return reg;
    }

    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            public void configure() throws Exception {
                // the reports from the seda queue is processed by our processor
                // before they are written to files in the target/reports directory
                from("direct:reports").processRef("processReport").to("file://target/test-reports", "mock:result");
            }
        };
    }

    private static class ProcessReport implements Processor {

        public void process(Exchange exchange) throws Exception {
            String body = exchange.getIn().getBody(String.class);
            // do some business logic here

            // set the output to the file
            exchange.getOut().setBody(body);

            // set the output filename using java code logic, notice that this is done by setting
            // a special header property of the out exchange
            exchange.getOut().setHeader(Exchange.FILE_NAME, "report.txt");
        }

    }

Write to subdirectory using Exchange.FILE_NAME

Using a single route, it is possible to write a file to any number of subdirectories. If you have a route setup as such:

  <route>
    <from uri="bean:myBean"/>
    <to uri="file:/rootDirectory"/>
  </route> 

You can have myBean set the header Exchange.FILE_NAME to values such as:

Exchange.FILE_NAME = hello.txt => /rootDirectory/hello.txt
Exchange.FILE_NAME = foo/bye.txt => /rootDirectory/foo/bye.txt 

This allows you to have a single route to write files to multiple destinations.

Using expression for filenames

In this sample we want to move consumed files to a backup folder using today's date as a sub-folder name:

from("file://inbox?move=backup/${date:now:yyyyMMdd}/${file:name}").to("...");

See File Language for more samples.

Avoiding reading the same file more than once (idempotent consumer)

Camel supports Idempotent Consumer directly within the component so it will skip already processed files. This feature can be enabled by setting the idempotent=true option.

from("file://inbox?idempotent=true").to("...");

By default Camel uses a in memory based store for keeping track of consumed files, it uses a least recently used cache holding up to 1000 entries. You can plugin your own implementation of this store by using the idempotentRepository option using the \# sign in the value to indicate it's a referring to a bean in the Registry with the specified id.

   <!-- define our store as a plain spring bean -->
   <bean id="myStore" class="com.mycompany.MyIdempotentStore"/>

  <route>
    <from uri="file://inbox?idempotent=true&dempotentRepository=#myStore"/>
    <to uri="bean:processInbox"/>
  </route>

Camel will log at DEBUG level if it skips a file because it has been consumed before:

DEBUG FileConsumer is idempotent and the file has been consumed before. Will skip this file: target\idempotent\report.txt

Using a file based idempotent repository

In this section we will use the file based idempotent repository org.apache.camel.processor.idempotent.FileIdempotentRepository instead of the in-memory based that is used as default.
This repository uses a 1st level cache to avoid reading the file repository. It will only use the file repository to store the content of the 1st level cache. Thereby the repository can survive server restarts. It will load the content of the file into the 1st level cache upon startup. The file structure is very simple as it stores the key in separate lines in the file. By default, the file store has a size limit of 1mb. When the file grows larger Camel will truncate the file store, rebuilding the content by flushing the 1st level cache into a fresh empty file.

We configure our repository using Spring XML creating our file idempotent repository and define our file consumer to use our repository with the idempotentRepository using \# sign to indicate Registry lookup:

    <!-- this is our file based idempotent store configured to use the .filestore.dat as file -->
    <bean id="fileStore" class="org.apache.camel.processor.idempotent.FileIdempotentRepository">
        <!-- the filename for the store -->
        <property name="fileStore" value="target/fileidempotent/.filestore.dat"/>
        <!-- the max filesize in bytes for the file. Camel will trunk and flush the cache
             if the file gets bigger -->
        <property name="maxFileStoreSize" value="512000"/>
        <!-- the number of elements in our store -->
        <property name="cacheSize" value="250"/>
    </bean>

    <camelContext xmlns="http://camel.apache.org/schema/spring">
        <route>
            <from uri="file://target/fileidempotent/?idempotent=true&dempotentRepository=#fileStore&ove=done/${file:name}"/>
            <to uri="mock:result"/>
        </route>
    </camelContext>

Using a JPA based idempotent repository

In this section we will use the JPA based idempotent repository instead of the in-memory based that is used as default.

First we need a persistence-unit in META-INF/persistence.xml where we need to use the class org.apache.camel.processor.idempotent.jpa.MessageProcessed as model.

  <persistence-unit name="idempotentDb" transaction-type="RESOURCE_LOCAL">
    <class>org.apache.camel.processor.idempotent.jpa.MessageProcessed</class>

    <properties>
      <property name="openjpa.ConnectionURL" value="jdbc:derby:target/idempotentTest;create=true"/>
      <property name="openjpa.ConnectionDriverName" value="org.apache.derby.jdbc.EmbeddedDriver"/>
      <property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema"/>
      <property name="openjpa.Log" value="DefaultLevel=WARN, Tool=INFO"/>
    </properties>
  </persistence-unit>

Then we need to setup a Spring jpaTemplate in the spring XML file:

    <!-- this is standard spring JPA configuration -->
    <bean id="jpaTemplate" class="org.springframework.orm.jpa.JpaTemplate">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
        <!-- we use idempotentDB as the persitence unit name defined in the persistence.xml file -->
        <property name="persistenceUnitName" value="idempotentDb"/>
    </bean>

And finally we can create our JPA idempotent repository in the spring XML file as well:

    <!-- we define our jpa based idempotent repository we want to use in the file consumer -->
    <bean id="jpaStore" class="org.apache.camel.processor.idempotent.jpa.JpaMessageIdRepository">
        <!-- Here we refer to the spring jpaTemplate -->
        <constructor-arg index="0" ref="jpaTemplate"/>
        <!-- This 2nd parameter is the name  (= a cateogry name).
             You can have different repositories with different names -->
        <constructor-arg index="1" value="FileConsumer"/>
    </bean>

And yes then we just need to refer to the jpaStore bean in the file consumer endpoint using the idempotentRepository using the \# syntax option:

  <route>
    <from uri="file://inbox?idempotent=true&dempotentRepository=#jpaStore"/>
    <to uri="bean:processInbox"/>
  </route>

Filter using org.apache.camel.component.file.GenericFileFilter

Camel supports pluggable filtering strategies. You can then configure the endpoint with such a filter to skip certain files being processed.

In the sample we have built our own filter that skips files starting with skip in the filename:

    public class MyFileFilter<T> implements GenericFileFilter<T> {
        public boolean accept(GenericFile<T> file) {
            // we want all directories
            if (file.isDirectory()) {
                return true;
            }
            // we dont accept any files starting with skip in the name
            return !file.getFileName().startsWith("skip");
        }
    }

And then we can configure our route using the filter attribute to reference our filter (using \# notation) that we have defined in the spring XML file:

   <!-- define our sorter as a plain spring bean -->
   <bean id="myFilter" class="com.mycompany.MyFileSorter"/>

  <route>
    <from uri="file://inbox?filter=#myFilter"/>
    <to uri="bean:processInbox"/>
  </route>

Filtering using ANT path matcher

The ANT path matcher is shipped out-of-the-box in the camel-spring jar. So you need to depend on camel-spring if you are using Maven.
The reasons is that we leverage Spring's AntPathMatcher to do the actual matching.

The file paths is matched with the following rules:

• ? matches one character

• * matches zero or more characters

• ** matches zero or more directories in a path

The sample below demonstrates how to use it:

    <camelContext xmlns="http://camel.apache.org/schema/spring">
        <template id="camelTemplate"/>

        <!-- use myFilter as filter to allow setting ANT paths for which files to scan for -->
        <endpoint id="myFileEndpoint" uri="file://target/antpathmatcher?recursive=true&ilter=#myAntFilter"/>

        <route>
            <from ref="myFileEndpoint"/>
            <to uri="mock:result"/>
        </route>
    </camelContext>

    <!-- we use the antpath file filter to use ant paths for includes and exlucde -->
    <bean id="myAntFilter" class="org.apache.camel.component.file.AntPathMatcherGenericFileFilter">
        <!-- include and file in the subfolder that has day in the name -->
        <property name="includes" value="**/subfolder/**/*day*"/>
        <!-- exclude all files with bad in name or .xml files. Use comma to seperate multiple excludes -->
        <property name="excludes" value="**/*bad*,**/*.xml"/>
    </bean>

Sorting using Comparator

Camel supports pluggable sorting strategies. This strategy it to use the build in java.util.Comparator in Java. You can then configure the endpoint with such a comparator and have Camel sort the files before being processed.

In the sample we have built our own comparator that just sorts by file name:

    public class MyFileSorter<T> implements Comparator<GenericFile<T>> {
        public int compare(GenericFile<T> o1, GenericFile<T> o2) {
            return o1.getFileName().compareToIgnoreCase(o2.getFileName());
        }
    }

And then we can configure our route using the sorter option to reference to our sorter (mySorter) we have defined in the spring XML file:

   <!-- define our sorter as a plain spring bean -->
   <bean id="mySorter" class="com.mycompany.MyFileSorter"/>

  <route>
    <from uri="file://inbox?sorter=#mySorter"/>
    <to uri="bean:processInbox"/>
  </route>

Sorting using sortBy

Camel supports pluggable sorting strategies. This strategy it to use the File Language to configure the sorting. The sortBy option is configured as follows:

sortBy=group 1;group 2;group 3;...

Where each group is separated with semi colon. In the simple situations you just use one group, so a simple example could be:

sortBy=file:name

This will sort by file name, you can reverse the order by prefixing reverse: to the group, so the sorting is now Z..A:

sortBy=reverse:file:name

As we have the full power of File Language we can use some of the other parameters, so if we want to sort by file size we do:

sortBy=file:length

You can configure to ignore the case, using ignoreCase: for string comparison, so if you want to use file name sorting but to ignore the case then we do:

sortBy=ignoreCase:file:name

You can combine ignore case and reverse, however reverse must be specified first:

sortBy=reverse:ignoreCase:file:name

In the sample below we want to sort by last modified file, so we do:

sortBy=file:modifed

And then we want to group by name as a 2nd option so files with same modifcation is sorted by name:

sortBy=file:modifed;file:name

Now there is an issue here, can you spot it? Well the modified timestamp of the file is too fine as it will be in milliseconds, but what if we want to sort by date only and then subgroup by name?
Well as we have the true power of File Language we can use the its date command that supports patterns. So this can be solved as:

sortBy=date:file:yyyyMMdd;file:name

Yeah, that is pretty powerful, oh by the way you can also use reverse per group, so we could reverse the file names:

sortBy=date:file:yyyyMMdd;reverse:file:name

Using GenericFileProcessStrategy

The option processStrategy can be used to use a custom GenericFileProcessStrategy that allows you to implement your own begin, commit and rollback logic.
For instance lets assume a system writes a file in a folder you should consume. But you should not start consuming the file before another ready file has been written as well.

So by implementing our own GenericFileProcessStrategy we can implement this as:

• In the begin() method we can test whether the special ready file exists. The begin method returns a boolean to indicate if we can consume the file or not.

• In the abort() method (Camel 2.10) special logic can be executed in case the begin operation returned false, for example to cleanup resources etc.

• in the commit() method we can move the actual file and also delete the ready file.

Using filter

The filter option allows you to implement a custom filter in Java code by implementing the org.apache.camel.component.file.GenericFileFilter interface. This interface has an accept method that returns a boolean. Return true to include the file, and false to skip the file. From Camel 2.10 onwards, there is a isDirectory method on GenericFile whether the file is a directory. This allows you to filter unwanted directories, to avoid traversing down unwanted directories.

For example to skip any directories which starts with "skip" in the name, can be implemented as follows:

    public class MyDirectoryFilter<T> implements GenericFileFilter<T> {

        public boolean accept(GenericFile<T> file) {
            // remember the name due unit testing (should not be needed in regular use-cases)
            names.add(file.getFileName());
            
            // we dont accept any files within directory starting with skip in the name
            if (file.isDirectory() && file.getFileName().startsWith("skip")) {
                return false;
            }

            return true;
        }

    }

How to use the Camel error handler to deal with exceptions triggered outside the routing engine

The file and ftp consumers, will by default try to pickup files. Only if that is successful then a Camel Exchange can be created and passed in the Camel routing engine.
When the Exchange is processed by the routing engine, then the Camel Error Handling takes over (eg the onException / errorHandler in the routes).
However outside the scope of the routing engine, any exceptions handling is component specific. Camel offers a org.apache.camel.spi.ExceptionHandler that allows components
to use that as a pluggable hook for end users to use their own implementation. Camel offers a default LoggingExceptionHandler that will log the exception at ERROR/WARN level.
For the file and ftp components this would be the case. However if you want to bridge the ExceptionHandler so it uses the Camel Error Handling, then
you need to implement a custom ExceptionHandler that will handle the exception by creating a Camel Exchange and send it to the routing engine; then the error handling of the routing engine can get triggered.

Here is such an example based upon an unit test.

First we have a custom ExceptionHandler where you can see we deal with the exception by sending it to a Camel Endpoint named "direct:file-error":

    /**
     * Custom {@link ExceptionHandler} to be used on the file consumer, to send
     * exceptions to a Camel route, to let Camel deal with the error.
     */
    private static class MyExceptionHandler implements ExceptionHandler {

        private ProducerTemplate template;

        /**
         * We use a producer template to send a message to the Camel route
         */
        public void setTemplate(ProducerTemplate template) {
            this.template = template;
        }

        @Override
        public void handleException(Throwable exception) {
            handleException(exception.getMessage(), exception);
        }

        @Override
        public void handleException(String message, Throwable exception) {
            handleException(exception.getMessage(), null, exception);
        }

        @Override
        public void handleException(final String message, final Exchange originalExchange, final Throwable exception) {
            // send the message to the special direct:file-error endpoint, which will trigger exception handling
            //
            template.send("direct:file-error", new Processor() {
                @Override
                public void process(Exchange exchange) throws Exception {
                    // set an exception on the message from the start so the error handling is triggered
                    exchange.setException(exception);
                    exchange.getIn().setBody(message);
                }
            });
        }
    }

Then we have a Camel route that uses the Camel routing error handler, which is the onException where we handle any IOException being thrown.
We then send the message to the same "direct:file-error" endpoint, where we handle it by transforming it to a message, and then being sent to a Mock endpoint.
This is just for testing purpose. You can handle the exception in any custom way you want, such as using a Bean or sending an email etc.

Notice how we configure our custom MyExceptionHandler by using the consumer.exceptionHandler option to refer to #myExceptionHandler which is a id of the bean registered in the Registry. If using Spring XML or OSGi Blueprint, then that would be a <bean id="myExceptionHandler" class="com.foo.MyExceptionHandler"/>:

    @Override
    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                // to handle any IOException being thrown
                onException(IOException.class)
                    .handled(true)
                    .log("IOException occurred due: ${exception.message}")
                    // as we handle the exception we can send it to direct:file-error,
                    // where we could send out alerts or whatever we want
                    .to("direct:file-error");

                // special route that handles file errors
                from("direct:file-error")
                    .log("File error route triggered to deal with exception ${exception?.class}")
                    // as this is based on unit test just transform a message and send it to a mock
                    .transform().simple("Error ${exception.message}")
                    .to("mock:error");

                // this is the file route that pickup files, notice how we use our custom exception handler on the consumer
                // the exclusiveReadLockStrategy is only configured because this is from an unit test, so we use that to simulate exceptions
                from("file:target/nospace?exclusiveReadLockStrategy=#myReadLockStrategy&consumer.exceptionHandler=#myExceptionHandler")
                    .convertBodyTo(String.class)
                    .to("mock:result");
            }
        };
    }

The source code for this example can be seen here

Using consumer.bridgeErrorHandler

Available as of Camel 2.10

If you want to use the Camel Error Handler to deal with any exception occurring in the file consumer, then you can enable the consumer.bridgeErrorHandler option as shown below:

    @Override
    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                // to handle any IOException being thrown
                onException(IOException.class)
                    .handled(true)
                    .log("IOException occurred due: ${exception.message}")
                    .transform().simple("Error ${exception.message}")
                    .to("mock:error");

                // this is the file route that pickup files, notice how we bridge the consumer to use the Camel routing error handler
                // the exclusiveReadLockStrategy is only configured because this is from an unit test, so we use that to simulate exceptions
                from("file:target/nospace?exclusiveReadLockStrategy=#myReadLockStrategy&consumer.bridgeErrorHandler=true")
                    .convertBodyTo(String.class)
                    .to("mock:result");
            }
        };
    }

So all you have to do is to enable this option, and the error handler in the route will take it from there.

Debug logging

This component has log level TRACE that can be helpful if you have problems.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

• File Language

• FTP

• Polling Consumer