Netbeans Swing GUI构建器不能与Java模块项目和Maven一起工作

Question

我想使用NetBeans的Swing GUI构建器以及Maven项目和java模块。似乎GUI构建器找不到编译的类，如果它们是作为java模块的一部分编译的。它给出了错误“加载组件（...）中的错误不能加载组件类（...）”（参见示例末尾截图中的整个错误）

我把它归结为一个最小的例子，使用Netbeans 11：

>

文件>New Project>Java with Maven>Java Application（使用默认建议并单击Finish）

使用GUI构建器，将JPanel的一个实例添加到JFrame，方法是在设计模式下打开JFrame，并将JPanel拖动到JFrame。

通过添加文件src/main/java/module-info.java，将项目更新为使用java模块：

module MavenGuiTest {
    requires java.desktop;
    requires java.logging;
}

单击Yes，以下内容将被添加到pom.xml中：

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.1</version>
            </plugin>
        </plugins>
    </build>

java.lang.ClassNotFoundException: com.mycompany.mavenproject1.NewJPanel
    at org.netbeans.modules.form.project.ProjectClassLoader.findClass(ProjectClassLoader.java:163)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    at org.netbeans.modules.form.project.FormClassLoader.findClass(FormClassLoader.java:58)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:398)
    at org.netbeans.modules.form.project.ClassPathUtils.loadClass(ClassPathUtils.java:89)
    at org.netbeans.modules.form.FormUtils.loadClass(FormUtils.java:1552)
    at org.netbeans.modules.form.PersistenceObjectRegistry.loadClass(PersistenceObjectRegistry.java:73)
    at org.netbeans.modules.form.GandalfPersistenceManager.restoreComponent(GandalfPersistenceManager.java:673)
    at org.netbeans.modules.form.GandalfPersistenceManager.loadComponent(GandalfPersistenceManager.java:949)
    at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:484)
    at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:260)
    at org.netbeans.modules.form.FormEditor$2.run(FormEditor.java:327)
    at org.netbeans.modules.form.FormLAF$2.run(FormLAF.java:268)
    at org.netbeans.modules.openide.util.NbMutexEventProvider$Event.doEventAccess(NbMutexEventProvider.java:115)
    at org.netbeans.modules.openide.util.NbMutexEventProvider$Event.readAccess(NbMutexEventProvider.java:75)
    at org.netbeans.modules.openide.util.LazyMutexImplementation.readAccess(LazyMutexImplementation.java:71)
    at org.openide.util.Mutex.readAccess(Mutex.java:225)
    at org.netbeans.modules.form.FormLAF.executeWithLookAndFeel(FormLAF.java:251)
    at org.netbeans.modules.form.FormEditor.loadFormData(FormEditor.java:324)
    at org.netbeans.modules.nbform.FormEditorSupport.loadOpeningForm(FormEditorSupport.java:436)
    at org.netbeans.modules.nbform.FormDesignerTC.loadForm(FormDesignerTC.java:256)
    at org.netbeans.modules.nbform.FormDesignerTC.access$300(FormDesignerTC.java:64)
    at org.netbeans.modules.nbform.FormDesignerTC$PreLoadTask$1.run(FormDesignerTC.java:245)
    at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313)
    at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770)
    at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
    at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
    at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740)
    at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:136)
    at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
    at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
    at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
    at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
    at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

我想不出如何修复它，也没有找到任何解决办法。

Answer 1

这只是一个警告，而不是错误。即使发生这种情况，也可以运行此项目。此警告显示这些事情何时发生。

1. 将一个版本切换到另一个版本时。
2. 项目中的库未使用或已损坏。尝试删除此类库。
3. 您以前有一个自定义GUI组件，您修改了该类，新IDE不再识别它。那里只需按允许编辑按钮，并执行清洁和构建（扫帚和锤子图标）。构建完成后，关闭NetBeans并重新打开它。