Ant 简明教程

Ant - If Else Arguments

Ant 允许基于传递的条件来运行目标。我们可以使用 if 语句或 unless 语句。

Ant allows to run targets based on passed conditions. We can use if statement or unless statement.

Syntax

<target name="copy" if="copyFile">
   <echo>Files are copied.</echo>
</target>
<target name="move" unless="copyFile">
   <echo>Files are moved.</echo>
</target>

我们将使用 -Dproperty 将变量（如 copyFile）传递给构建任务。将要定义变量，此处变量的值无关紧要。

We’ll be using -Dproperty to pass varible like copyFile to the build task. The variable is to be defined, the value of variable is of no relevance here.

Example

使用以下内容创建 build.xml −

Create build.xml with the following content −

<?xml version="1.0"?>
<project name="sample" basedir="." default="copy">
   <target name="copy" if="copyFile">
      <echo>Files are copied.</echo>
   </target>
   <target name="move" unless="copyFile">
      <echo>Files are moved.</echo>
   </target>
</project>

Output

在上述构建文件上运行 Ant 会生成以下输出：

Running Ant on the above build file produces the following output −

F:\tutorialspoint\ant>ant -DcopyFile=true
Buildfile: F:\tutorialspoint\ant\build.xml

copy:
   [echo] Files are copied.

BUILD SUCCESSFUL
Total time: 0 seconds

F:\tutorialspoint\ant>ant move
Buildfile: F:\tutorialspoint\ant\build.xml

move:
   [echo] Files are moved.

BUILD SUCCESSFUL
Total time: 0 seconds

F:\tutorialspoint\ant>ant move -DcopyFile=true
Buildfile: F:\tutorialspoint\ant\build.xml

move:

BUILD SUCCESSFUL
Total time: 0 seconds

F:\tutorialspoint\ant>ant move -DcopyFile=false
Buildfile: F:\tutorialspoint\ant\build.xml

move:

BUILD SUCCESSFUL
Total time: 0 seconds

F:\tutorialspoint\ant>ant move -DcopyFile=true
Buildfile: F:\tutorialspoint\ant\build.xml

move:

BUILD SUCCESSFUL
Total time: 0 seconds

F:\tutorialspoint\ant>ant move
Buildfile: F:\tutorialspoint\ant\build.xml

move:
   [echo] Files are moved.

BUILD SUCCESSFUL
Total time: 0 seconds

F:\tutorialspoint\ant>