How do I load optional task sshexec into Ant in a no-configuration manner?

问题

I am using sshexec, which depends on jsch-0.1.48.jar. I can't just put that into the ant/lib directory because other users wishing to use the same build script will have to make a configuration on their machine before they can do so.

What I want to do is to be able to reference jsch-0.1.48.jar as part of the project. Currently, I have it sitting in project/libs directory and I am trying something like:

<property name="lib" location="lib"/>

<taskdef name="sshexec" classname="org.apache.tools.ant.taskdefs.optional.ssh.SSHExec">
  <classpath>
    <pathelement location="${lib}/jsch-0.1.48.jar"/>  
  </classpath>
</taskdef> 

<target name="sshcmd" description="ssh command">    
    <sshexec host="X.X.X.X" username="USER" password="PASS" command="cmd" trust="true"/>
</target>

But that's not working:

C:\dev\trunk\project:>ant sshcmd
Buildfile: C:\dev\trunk\project\build.xml

BUILD FAILED
C:\dev\trunk\project\build.xml:275: taskdef A class needed by class org.apache.tools.ant.taskdefs.optional.ssh.SSHExec cannot be found: com/jcraft/jsch/Logger
using the classloader AntClassLoader[C:\dev\trunk\project\lib\jsch-0.1.48.jar]

Total time: 0 seconds

回答1:

The sshexec task is built into ANT, you do not need to invoke a taskdef operation to use it. All that's missing is the jsch jar.

This can installed using a bootstrap target as follows (from Maven Central):

<target name="bootstrap" description="Install missing jars">
    <mkdir dir="${user.home}/.ant/lib"/>
    <get src="http://search.maven.org/remotecontent?filepath=com/jcraft/jsch/0.1.48/jsch-0.1.48.jar" dest="${user.home}/.ant/lib/jsch.jar"/>
</target>

This target only needs to be run once, after which the ANT sshexec task will work as expected on the developer's PC.

Update

If you don't want to download jars another mechanism to pass the location of ANT libraries from the command line as follows:

ant -lib /path/to/project/lib/dir ...

For more details on ANT library management, I refer you to the ANT manual

回答2:

The jsch jar is packaged with my project. So instead of downloading it, I am copying it into the ant library. The build will fail the first time it is run, which is fine for my purposes. It will succeed the second time because the jar will be in the library and would be loaded at start.

<target name="jschset" description="Set the jar">   
    <copy file="${lib}/jsch-0.1.48.jar" tofile="${ant.home}/lib/jsch-0.1.48.jar"/>
</target>

来源：https://stackoverflow.com/questions/12752124/how-do-i-load-optional-task-sshexec-into-ant-in-a-no-configuration-manner