Question

我正在使用Windows 7，Eclipse 4.2.1和（尝试使用）MigLayout 4.0。

我已经下载了miglayout-4.0-swing.jar，将其添加到我的类路径中并在Groovy Console中成功运行以下脚本：

import groovy.swing.SwingBuilder
import groovy.swing.factory.LayoutFactory
import javax.swing.WindowConstants as WC
import net.miginfocom.swing.MigLayout

def swing = new SwingBuilder()
swing.registerBeanFactory('migLayout', MigLayout)

swing.build {
    frame(id: 'eventScrollPanel', pack: true, show: true,
      defaultCloseOperation: WC.EXIT_ON_CLOSE) {
        migLayout(layoutConstraints: "fill, debug", columnConstraints: "",
        rowConstraints: "")
        panel() {
            label(text: "test")
        }
    }
}

在Eclipse中，我已将外部jar文件添加到我的JDK并检查它是否出现在Project =＆gt;中属性=＆gt; Java Build Path =＆gt; Libraries选项卡=＆gt; JRE系统库[jdk1.7.0_09]。但是，脚本失败并出现以下错误：

Caught: java.lang.ExceptionInInitializerError
java.lang.ExceptionInInitializerError
    at net.miginfocom.layout.UnitValue.<init>(Unknown Source)
    at net.miginfocom.layout.UnitValue.<clinit>(Unknown Source)
    at net.miginfocom.layout.PlatformDefaults.<clinit>(Unknown Source)
    at net.miginfocom.swing.MigLayout.<init>(Unknown Source)
    at net.miginfocom.swing.MigLayout.<init>(Unknown Source)
    at MigLayoutExamples$_run_closure1_closure2.doCall(MigLayoutExamples.groovy:12)
    at MigLayoutExamples$_run_closure1_closure2.doCall(MigLayoutExamples.groovy)
    at MigLayoutExamples$_run_closure1.doCall(MigLayoutExamples.groovy:10)
    at MigLayoutExamples$_run_closure1.doCall(MigLayoutExamples.groovy)
    at MigLayoutExamples.run(MigLayoutExamples.groovy:9)
Caused by: java.lang.NullPointerException
    at net.miginfocom.layout.LayoutUtil.hasBeans(Unknown Source)
    at net.miginfocom.layout.LayoutUtil.<clinit>(Unknown Source)
    ... 10 more

此外，Eclipse强调脚本第12行开头的migLayout引用，即Eclipse canot解析引用。

感谢所有人的帮助。

Answer 1

看起来line是罪魁祸首。

LayoutUtil.class.getClassLoader().loadClass("java.beans.Beans");

最新的jar是4.2，这个问题似乎已经用try-catch块修复了尝试使用这些罐子。它们可从Maven回购中获得。 http://mvnrepository.com/artifact/com.miglayout/miglayout-swing/4.2
http://mvnrepository.com/artifact/com.miglayout/miglayout-core/4.2

不能在Eclipse中使用MigLayout，但它可以在Groovy Console中使用

1 个答案: