Ant 用特征控制Ant

?输出，在特征output在定义时输出内容，未定义时不输出内容，与特征的值无关：

? ? 或
输出：
?输出：
e:\antspace\property>antBuildfile: e:\antspace\property\build.xmlmkbuild:   [delete] Deleting directory e:\antspace\property\build    [mkdir] Created dir: e:\antspace\property\buildbuildjava:BUILD SUCCESSFULTotal time: 0 secondse:\antspace\property>ant -Dbuild=aBuildfile: e:\antspace\property\build.xmlmkbuild:   [delete] Deleting directory e:\antspace\property\build    [mkdir] Created dir: e:\antspace\property\buildbuildjava:    [javac] Compiling 1 source file to e:\antspace\property\buildBUILD SUCCESSFULTotal time: 0 seconds
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