构建 jar 后出现 NullPointerException

Question

我有一个使用 IntelliJ 开发的 JavaFX 项目，当我运行那里的程序一切正常时。

但是当我运行 mvn clean package 并尝试运行构建的 jar 时，我得到以下 Exception:

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
        at de.application.component.main.FilterListCell.setParent(FilterListCell.java:212)
        at de.application.controller.MainController.lambda$initialize(MainController.java:183)
        at javafx.scene.control.skin.ListViewSkin.createCell(ListViewSkin.java:432)
        at javafx.scene.control.skin.ListViewSkin.lambda$new(ListViewSkin.java:207)
        at javafx.scene.control.skin.VirtualFlow.getCell(VirtualFlow.java:1672)
        at javafx.scene.control.skin.VirtualFlow.getCellLength(VirtualFlow.java:1801)
        at javafx.scene.control.skin.VirtualFlow.computeViewportOffset(VirtualFlow.java:2639)
        at javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1245)
        at javafx.scene.Parent.layout(Parent.java:1204)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Scene.doLayoutPass(Scene.java:576)
        at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2482)
        at com.sun.javafx.tk.Toolkit.lambda$runPulse(Toolkit.java:412)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:411)
        at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:438)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:519)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:499)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulseFromQueue(QuantumToolkit.java:492)
        at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit(QuantumToolkit.java:320)
        at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.lambda$runLoop(WinApplication.java:174)
        at java.base/java.lang.Thread.run(Thread.java:834)

这是失败的行：

public void setParent(ListView<CompositeFilter> parent) {
    this.parent = parent;
    root.prefWidthProperty().bind(parent.widthProperty().subtract(16)); // this fails
}

root 是空的，我不明白，因为我在控制器中这样声明它

    @FXML
    public AnchorPane root;

这是 fxml 文件：

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<AnchorPane fx:id="root" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity"
            minWidth="-Infinity" prefHeight="200.0" xmlns="http://javafx.com/javafx/11.0.1"
            xmlns:fx="http://javafx.com/fxml/1"
            fx:controller="de.application.component.main.FilterListCell">
  <HBox alignment="CENTER_LEFT" AnchorPane.leftAnchor="8.0" AnchorPane.topAnchor="8.0" AnchorPane.rightAnchor="8.0">
   <!-- some content -->
  </HBox>
</AnchorPane>

我不知道为什么会这样，我检查过 IntelliJ 使用与我相同的 JDK。

也许这是我的 pom 的问题？

这里是：

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.7.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>de.group</groupId>
  <artifactId>application</artifactId>
  <version>0.1-SNAPSHOT</version>

  <properties>
    <java.version>11</java.version>
    <javafx.version>11.0.2</javafx.version>
    <maven.compiler.plugin.version>3.8.1</maven.compiler.plugin.version>
  </properties>

  <dependencies>
    <!-- JavaFX -->
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-controls</artifactId>
      <version>${javafx.version}</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-fxml</artifactId>
      <version>${javafx.version}</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-graphics</artifactId>
      <version>${javafx.version}</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-base</artifactId>
      <version>${javafx.version}</version>
    </dependency>

    <dependency>
      <groupId>org.controlsfx</groupId>
      <artifactId>controlsfx</artifactId>
      <version>11.0.1</version>
    </dependency>
    <!-- Spring Boot -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
    </dependency>

    <!-- Other -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.module</groupId>
      <artifactId>jackson-module-parameter-names</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jdk8</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jsr310</artifactId>
    </dependency>

    <dependency>
      <groupId>net.rgielen</groupId>
      <artifactId>javafx-weaver-spring</artifactId>
      <version>1.2.0</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-configuration-processor</artifactId>
      <optional>true</optional>
    </dependency>

    <!-- Test -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>${maven.compiler.plugin.version}</version>
        <configuration>
          <source>${java.version}</source>
          <target>${java.version}</target>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

</project>

所有帮助将不胜感激。

编辑

MainController 的代码片段是这样的

lstFilter.setCellFactory(compositeFilterListView -> {
            FxControllerAndView<FilterListCell, Node> cell = fxWeaver.load(FilterListCell.class);
            if(cell.getView().isPresent()) {
                cell.getView().get().setVisible(false);
                cell.getController().setGraphic(cell.getView().get());
            }
            cell.getController().setParent(lstFilter); // setParent fails
            return cell.getController();
        });

这只是 Listview lstFilter 的 CellFactory。真正的问题是运行通过 Intellij 和运行通过 Intellij 构建 jar 之间的差异，在这种情况下不会发生此错误。

Answer 1

所以我找到了解决问题的办法：

问题是找不到我的 fxml 文件。我仍然不确定为什么。控制器 class 被称为 FilterListView，我的 fxml 文件被称为 filterListView.fxml。现在我将 fxml 文件重命名为 FilterListView.fxml 并且它有效。

有谁知道为什么 class 路径在运行 jar 时似乎区分大小写，而在 IDE 中的运行时似乎不区分大小写？

构建 jar 后出现 NullPointerException

NullPointerException after building jar

java

javafx

maven

java-11