Groovy, hello world.

下载了eclipse groovy plugin，成功安装后准备写一个hello world，发现了两个问题。

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1. 第一个问题是这样的。参看这个网页。

http://groovy.codehaus.org/Eclipse+Plugin

网页中提到需要将eclipse java project的default output folder设置为bin-groovy。详细描述见下面英文。

Create a Groovy Project

To create a basic Groovy project in Eclipse perform the following steps:

• Go to: File -> New -> Project
• Select Java Project and press Next
• In the Project Name field enter the name of your project (GroovyJava for this example)
• Under Project Layout select Create separate source and output folders and press Finish
• In the Package Explorer find the newly created project, right click, and select Groovy -> Add Groovy Nature

So far you should have a src folder, a bin-groovy folder, and several libraries. There is also a bin folder that was created by Eclipse, but is hidden due to exclusion filters. The next steps are needed to make the bin-groovy folder the default output folder, and to connect it to the src folder so that the debugger will know where to find the associated source and classes:

• In the Package Explorer, right click on the "GroovyJava" project, and select: Build Path -> Configure Build Path
• Select the Source tab and then use the Browse button to change the Default Output Folder from bin to bin-groovy
• Press OK, OK

This will expose the bin folder in the Package Explorer. I'm not sure why the plugin creates a bin-groovy directory. Perhaps there are other "bin" files that are best kept separate from the Groovy classes, or perhaps one of the original versions of Eclipse didn't create a "bin" directory automatically. Some day when someone has a clear idea of the usefulness of this, or lack thereof, we can clean up my instructions.

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2. 第二个问题是插件的问题。写了一个简单的脚本后，运行的时候会抛出异常。

这是因为在点击【右键工程文件夹-->Groovy-->Import Groovy Libs into Project】按钮的时候，并没有将Groovy需要的jar包拷贝到工程的classpath中，手动将%Groovy_home%/lib路径下的jar包拷贝到工程中，并设置为classpath。运行hello world，一切搞定！～