Apache Ant编写build.xml的自动提示 ANT DTD

大家都知道Eclipse的自动输入或者自动完成的功能是用XML的DTD文件来控制的，但是安装了ANT的插件之后会发现Apache并没有为我们直接提供书写build.xml的DTD文件，可能是由于扩张方面的考虑。在Apache的 FAQ里有提到

An incomplete DTD can be created by the <antstructure> task - but this one has a few problems:

It doesn't know about required attributes. Only manual tweaking of this file can help here.
It is not complete - if you add new tasks via <taskdef> it won't know about it. See this page by Michel Casabianca for a solution to this problem. Note that the DTD you can download at this page is based on Apache Ant 0.3.1.
It may even be an invalid DTD. As Ant allows tasks writers to define arbitrary elements, name collisions will happen quite frequently - if your version of Ant contains the optional <test> and <junit> tasks, there are two XML elements named test (the task and the nested child element of <junit>) with different attribute lists. This problem cannot be solved; DTDs don't give a syntax rich enough to support this.

但是Ant的预订标签里面提供了生成DTD的方法。这里需要在%ANT_HOME%的lib目录下面加一个JAR包，

现在新建一个build.xml

内容如下

<?xml version="1.0" encoding="UTF-8"?>

<project>
　　<target name="makeantdtd">
　　　　<antstructure output="ant_DTD.dtd" />
　　</target>
</project>

然后使用ANT命令执行这个build.xml文件，在相同路径下就会生成ant_DTD.dtd

现在用Eclipse引用这个DTD就可以实现编写build.xml的时候的自动提示了。

建议把这放在%ANT_HOME%的 etc目录下，以免误删。

Eclipse的设置在：Window--Preference--XML--XML Catalog 点击Add 输入刚才那个生成的DTD文件地址，KEY_TYPE选 public ID , 取一个名字（KEY）,OK

现在按下alt+/ 就可以在有提示内容的地方弹出提示了

当然，如果想在输入的时候就直接弹出，要设置：Window--Preference--XML--XML File--Editor 在Content asist里，勾上 Automatically make suggestion, 然后在

Prompt when these characters are inserted 里面改成 <=:abcdefghijklmnopqrstuvwxyz ${

OK！当然这样做会是Eclipse的速度变慢，喜忧参半。

仅供参考学习交流。

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