本文基于windows7系统，mac上或许更简单些。本文参阅了无墨来点睛的文章，再此说明。
花了点时间，总算是试验成功，demo地址：http://pan.baidu.com/s/1c0dGm1i
ant可以去官网下载，地址是：http://ant.apache.org/ ，yuicompressor也可以去官网下一个https://github.com/yui/yuicompressor
demo的使用的ant版本是apache-ant-1.8.2，yuicompressor版本是yuicompressor-2.4.6。
另外由于ant是需要java运行环境的（一开始没看ant的说明，为此浪费了些时间），1.8的版本至少需要1.4的java jdk，可以从这里查阅：http://ant.apache.org/faq.html
java环境可以到官网下载，地址：http://www.oracle.com/technetwork/java/javase/downloads/index.html,请先安装java环境，然后配置java的环境变量，
配置好后可在cmd-》dos下输入java，查阅是否安装成功。然后配置ant的环境变量，配置好后，同样测试是否安装成功，cmd->dos->输入ant，出现类似下面的内容表示
安装成功：
到此环境才配置成功。下面看demo结构
我这是在vs里面建的小工程，仅仅是为了编写build的xml文件而已，再次说明，仅仅为编写xml，你完全可以自己手动在文件夹中做的。
其中核心的是build.xml文件，结构如下：
<?xml version="1.0" encoding="utf-8"?>build.bat的批处理文件是为了调用ant的，它的内容是：
./apache-ant-1.8.2/bin/ant -f ./build.xml是要运行bat文件即可，至于ant和yuicompressor xml语法解析说明，可以看文档，非常详细，而且你下载的demo里面有详细使用说明：
下面摘录的是yuicompressor的readme：
==============================================================================YUI Compressor==============================================================================NAME YUI Compressor - The Yahoo! JavaScript and CSS CompressorSYNOPSIS Usage: java -jar yuicompressor-x.y.z.jar [options] [input file] Global Options -h, --help Displays this information --typeSpecifies the type of the input file --charset Read the input file using --line-break Insert a line break after the specified column number -v, --verbose Display informational messages and warnings -o Place the output into or a file pattern. Defaults to stdout. JavaScript Options --nomunge Minify only, do not obfuscate --preserve-semi Preserve all semicolons --disable-optimizations Disable all micro optimizationsDESCRIPTION The YUI Compressor is a JavaScript compressor which, in addition to removing comments and white-spaces, obfuscates local variables using the smallest possible variable name. This obfuscation is safe, even when using constructs such as 'eval' or 'with' (although the compression is not optimal is those cases) Compared to jsmin, the average savings is around 20%. The YUI Compressor is also able to safely compress CSS files. The decision on which compressor is being used is made on the file extension (js or css)GLOBAL OPTIONS -h, --help Prints help on how to use the YUI Compressor --line-break Some source control tools don't like files containing lines longer than, say 8000 characters. The linebreak option is used in that case to split long lines after a specific column. It can also be used to make the code more readable, easier to debug (especially with the MS Script Debugger) Specify 0 to get a line break after each semi-colon in JavaScript, and after each rule in CSS. --type js|css The type of compressor (JavaScript or CSS) is chosen based on the extension of the input file name (.js or .css) This option is required if no input file has been specified. Otherwise, this option is only required if the input file extension is neither 'js' nor 'css'. --charset character-set If a supported character set is specified, the YUI Compressor will use it to read the input file. Otherwise, it will assume that the platform's default character set is being used. The output file is encoded using the same character set. -o outfile Place output in file outfile. If not specified, the YUI Compressor will default to the standard output, which you can redirect to a file. Supports a filter syntax for expressing the output pattern when there are multiple input files. ex: java -jar yuicompressor.jar -o '.css$:-min.css' *.css ... will minify all .css files and save them as -min.css -v, --verbose Display informational messages and warnings.JAVASCRIPT ONLY OPTIONS --nomunge Minify only. Do not obfuscate local symbols. --preserve-semi Preserve unnecessary semicolons (such as right before a '}') This option is useful when compressed code has to be run through JSLint (which is the case of YUI for example) --disable-optimizations Disable all the built-in micro optimizations.NOTES + If no input file is specified, it defaults to stdin. + Supports wildcards for specifying multiple input files. + The YUI Compressor requires Java version >= 1.4. + It is possible to prevent a local variable, nested function or function argument from being obfuscated by using "hints". A hint is a string that is located at the very beginning of a function body like so: function fn (arg1, arg2, arg3) { "arg2:nomunge, localVar:nomunge, nestedFn:nomunge"; ... var localVar; ... function nestedFn () { .... } ... } The hint itself disappears from the compressed file. + C-style comments starting with /*! are preserved. This is useful with comments containing copyright/license information. For example: /*! * TERMS OF USE - EASING EQUATIONS * Open source under the BSD License. * Copyright 2001 Robert Penner All rights reserved. */ becomes: /* * TERMS OF USE - EASING EQUATIONS * Open source under the BSD License. * Copyright 2001 Robert Penner All rights reserved. */MODIFIED RHINO FILES YUI Compressor uses a modified version of the Rhino library (http://www.mozilla.org/rhino/) The changes were made to support JScript conditional comments, preserved comments, unescaped slash characters in regular expressions, and to allow for the optimization of escaped quotes in string literals.COPYRIGHT AND LICENSE Copyright (c) 2011 Yahoo! Inc. All rights reserved. The copyrights embodied in the content of this file are licensed by Yahoo! Inc. under the BSD (revised) open source license.
ps，在网上也找了个在线的，地址是：http://ganquan.info/yui/?hl=zh-CN
另附相关文章供各位道友学习：
使用ANT和YUI压缩js
ant和yuicompressor 压缩css、js方案