build.xml：问题：无法创建任务或键入p4change原因

Question

在我的 RHEL 中的Ant脚本中，当我使用perforce命令“ P4Change”时出现错误提示。

错误：

 build.xml:638: Problem: failed to create task or type p4change
   Cause: the class org.apache.tools.ant.taskdefs.optional.perforce.P4Change was not found.

    This looks like one of Ant's optional components.
  Action: Check that the appropriate optional JAR exists in
    -/usr/share/ant/lib
    -/users/eswaran.p/.ant/lib
    -a directory added on the command line with the -lib argument

Do not panic, this is a common problem.
The commonest cause is a missing JAR.

This is not a bug; it is a configuration problem

请转介我， 1.如果要安装任何转速或 2.缺少任何配置

谢谢。