NFC Demo： com.google.common.base.Preconditions 找不到

我在eclipse里面导入NFC Demo会有很多类找不到:

import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;

不知道是否是sdk里面没有包进去呢？还是怎样。在网上搜索了，这些类都是在google的collection里面，但若你下载用Google-collection.jar，还是许多类找不到，你要用guava-r07.jar包。你到Guava的官网你就会看见这段话：

If your application ever ends up with both google-collect-1.0.jar and guava-r##.jar on the same classpath, simply remove the Google Collections JAR and you should be fine. If you don't remove it, it will either cause terrible problems (if it comes before guava in the classpath) or will never even be seen anyway (if it comes after).

所以你要下载guava-r07.jar，将其导入到NFC Demo里面，这样这个工程就可以运行了。下载地址：[url]http://code.google.com/p/guava-libraries/downloads/detail?name=guava-r07.zip&can=2&q=
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