ant 报错

在命令行执行: ant -p执行报错
G:\TNMS\client-dm\dm-boot\ivy>ant -p
Buildfile: build.xml
     [echo] The value of property local.settings.base.dir is empty
G:\TNMS\client-dm\dm-boot\ivy\build.xml:23: The following error occurred while e
xecuting this line:
G:\TNMS\settings\common.xml:19: The following error occurred while executing thi
s line:
G:\TNMS\settings\common-impl.xml:26: Problem: failed to create task or type antl
ib:org.apache.ivy.ant:settings
Cause: The name is undefined.
Action: Check the spelling.
Action: Check that any custom tasks/types have been declared.
Action: Check that any <presetdef>/<macrodef> declarations have taken place.
No types or tasks have been defined in this namespace yet

This appears to be an antlib declaration.
Action: Check that the implementing library exists in one of:
        -D:\Program Files (x86)\apache-ant-1.7.1\lib
        -C:\Users\xuwb\.ant\lib
        -a directory added on the command line with the -lib argument

原因：ant的lib目录下缺少ivy相关的jar

解决办法：把ivy的jar包（ivy-2.3.0-rc1.jar）复制到%ANT_HOME%\lib\下