Available in Apache Camel 2.3
The exec
component can be used to execute a
system command.
Maven users need to add the following dependency to their
pom.xml
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-exec</artifactId> <version>${camel-version}</version> </dependency>
where ${camel-version}
must be replaced by the
actual version of Apache Camel (2.3.0 or higher).
exec://executable[?options]
where executable
is the name, or file path, of
the system command that will be executed. If executable name is used
(e.g. exec:java
), the executable must in the
system path.
The supported uri options are listed Table 51:
Table 51. URI options
Name | Default value | Description |
---|---|---|
args | null |
The arguments of the executable. The arguments may be one or many whitespace-separated tokens, that can be
quoted with To include the quotes use |
workingDir | null |
The directory in which the command should be executed. If |
timeout | Long.MAX_VALUE |
The timeout, in milliseconds, after which the executable should be terminated. If the executable has not finished within the timeout, the component will send a termination request. |
outFile | null |
The name of a file, created by the executable, that should be considered as output of the executable. If no |
binding | A DefaultExecBinding instance | A reference to a org.apache.commons.exec.ExecBinding in the
Registry. |
commandExecutor | A DefaultCommandExecutor instance |
A reference to a The default command executor utilizes the commons-exec library. It adds a shutdown hook for every executed command. |
useStderrOnEmptyStdout | false | A boolean that dictates when stdin
is empty, it should fallback and use
stderr in the Message Body. |
The supported headers are defined in
org.apache.camel.component.exec.ExecBinding
.
Table 52. Message header options
Name | Type | Message | Description |
---|---|---|---|
ExecBinding.EXEC_COMMAND_EXECUTABLE
|
String
|
in
| The name of the system command that will be executed.
Overrides the executable in the
URI. |
ExecBinding.EXEC_COMMAND_ARGS
|
java.util.List<String>
|
in
| The arguments of the executable. The arguments are used
literally, no quoting is applied. Overrides existing
args in the URI. |
ExecBinding.EXEC_COMMAND_ARGS
|
String
|
in
| Apache Camel 2.5: The
arguments of the executable as a Single string where
each argument is whitespace separated (see
args in URI option). The
arguments are used literally, no quoting is applied.
Overrides existing args in the
URI. |
ExecBinding.EXEC_COMMAND_OUT_FILE
|
String
|
in
| The name of a file, created by the executable, that should
be considered as output of the executable. Overrides
existing outFile in the URI. |
ExecBinding.EXEC_COMMAND_TIMEOUT
|
long
|
in
| The timeout, in milliseconds, after which the executable
should be terminated. Overrides existing
timeout in the URI. |
ExecBinding.EXEC_COMMAND_WORKING_DIR
|
String
|
in
| The directory in which the command should be executed.
Overrides existing workingDir in the
URI. |
ExecBinding.EXEC_EXIT_VALUE
|
int
|
out
| The value of this header is the exit value of the executable. Typically not-zero exit values indicates abnormal termination. Note that the exit value is OS-dependent. |
ExecBinding.EXEC_STDERR
|
java.io.InputStream
|
out
| The value of this header points to the standard error stream
(stderr) of the executable. If no stderr is written, the
value is null . |
ExecBinding.EXEC_USE_STDERR_ON_EMPTY_STDOUT
|
boolean
|
in
| Indicates when the stdin is empty,
should we fallback and use stderr as the
body of the Message. By default this option is
false . |
If the in
message body, that that the
Exec
component receives, is convertible to
java.io.InputStream
, it is used to feed input
of the executable via its stdin. After the execution, the message
body is the result of the execution, that is
org.apache.camel.components.exec.ExecResult
instance containing the stdout, stderr, exit value and out file. The
component supports the following ExecResult
type
converters for convenience:
From | To |
---|---|
ExecResult
|
java.io.InputStream
|
ExecResult
|
String
|
ExecResult
|
byte []
|
ExecResult
|
org.w3c.dom.Document
|
If out file is used (the endpoint is configured with
outFile
, or there is
ExecBinding.EXEC_COMMAND_OUT_FILE
header) the
converters return the content of the out file. If no out file is
used, then the converters will use the stdout of the process for
conversion to the target type. For example refer to Usage Examples.
The example below executes wc
(word count,
Linux) to count the words in file
/usr/share/dict/words
. The word count
(output) is written in the standart output stream of
wc
.
from("direct:exec") .to("exec:wc?args=--words /usr/share/dict/words") .process(new Processor() { public void process(Exchange exchange) throws Exception { // By default, the body is ExecResult instance assertIsInstanceOf(ExecResult.class, exchange.getIn().getBody()); // Use the Camel Exec String type converter to convert the ExecResult to String // In this case, the stdout is considered as output String wordCountOutput = exchange.getIn().getBody(String.class); // do something with the word count } });
The example below executes java
with 2
arguments: -server
and
-version
, provided that
java
is in the system path.
from("direct:exec") .to("exec:java?args=-server -version")
The example below executes java
in
c:/temp
with 3 arguments:
-server
, -version
and the
sytem property user.name
.
from("direct:exec") .to("exec:c:/program files/jdk/bin/java?args=-server -version -Duser.name=Camel&workingDir=c:/temp")
The following example executes Apache Ant (Windows
only) with the build file CamelExecBuildFile.xml
,
provided that ant.bat
is in the system path, and
that CamelExecBuildFile.xml
is in the current
directory.
from("direct:exec") .to(exec:ant.bat?args=-f CamelExecBuildFile.xml")
In the next example, the ant.bat
command,
redirects the ant output to CamelExecOutFile.txt
with -l
. The file
CamelExecOutFile.txt
is used as out file with
outFile=CamelExecOutFile.txt
. The example
assumes that ant.bat
is in the system path, and
that CamelExecBuildFile.xml
is in the current
directory.
from("direct:exec") .to("exec:ant.bat?args=-f CamelExecBuildFile.xml -l CamelExecOutFile.txt&outFile=CamelExecOutFile.txt") .process(new Processor() { public void process(Exchange exchange) throws Exception { InputStream outFile = exchange.getIn().getBody(InputStream.class); assertIsInstanceOf(InputStream.class, outFile); // do something with the out file here } });