java - HtmlUnitDriver 抛出 java.lang.ExceptionInInitializerError

Question

我正在编写一个使用以下代码的 ant 任务:

public class Klazz extends Task{    
    public void execute() throws BuildException{

        HtmlUnitDriver driver = new HtmlUnitDriver();
        driver.get("file:///C:/sample/alltests-fails.html");
}

在 Eclipse 中，名为“test-project”的项目并使用“libs”文件夹，其中包含要添加到 classpath 中的 jar(ant.jar、selenium-server-standalone-2.44.0.jar)。如果我在 Eclipse 中运行代码，它工作正常，但作为 ant 任务运行时，它会抛出 java.lang.ExceptionInInitializerError 。下面是用于创建 jar(名为 custom-task.jar)文件的 build.xml 片段，该文件需要放入 %ant_home%\lib 文件夹中。

<target name="jar" depends="compile" >
        <mkdir dir="build/jar" />
        <jar destfile="${env.ANT_HOME}/lib/custom-task.jar">
            <fileset dir="build/classes" />         
            <restrict>
                <name name="**/*.class" />
                <archives> 
                    <zips>
                        <fileset dir="${basedir}/libs/" includes="**/*.jar" />
                    </zips>
                </archives>
            </restrict>
        </jar>
    </target>

可能是通过上面的“jar”任务创建jar时，外部jar/类未正确添加到类路径中，导致一些类文件丢失，从而导致ExceptionInInitializerError。预先感谢您对此提供的任何帮助。

下面是堆栈跟踪:

java.lang.ExceptionInInitializerError
        at org.cyberneko.html.HTMLScanner.scanEntityRef(HTMLScanner.java:1415)
        at org.cyberneko.html.HTMLScanner$ContentScanner.scan(HTMLScanner.java:2
059)
        at org.cyberneko.html.HTMLScanner.scanDocument(HTMLScanner.java:920)
        at org.cyberneko.html.HTMLConfiguration.parse(HTMLConfiguration.java:499
)
        at org.cyberneko.html.HTMLConfiguration.parse(HTMLConfiguration.java:452
)
        at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
        at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.pars
e(HTMLParser.java:926)
        at com.gargoylesoftware.htmlunit.html.HTMLParser.parse(HTMLParser.java:2
45)
        at com.gargoylesoftware.htmlunit.html.HTMLParser.parseHtml(HTMLParser.ja
va:191)


       at com.gargoylesoftware.htmlunit.DefaultPageCreator.createHtmlPage(Defau
ltPageCreator.java:268)
        at com.gargoylesoftware.htmlunit.DefaultPageCreator.createPage(DefaultPa
geCreator.java:156)
        at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseInto(WebClient
.java:455)
        at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:329)
        at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:394)
        at org.openqa.selenium.htmlunit.HtmlUnitDriver.get(HtmlUnitDriver.java:4
77)
        at org.openqa.selenium.htmlunit.HtmlUnitDriver.get(HtmlUnitDriver.java:4
66)

at mypkg.Klazz.execute(Klazz.java:15)

       at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
        at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.jav
a:106)
        at org.apache.tools.ant.Task.perform(Task.java:348)
        at org.apache.tools.ant.Target.execute(Target.java:435)
        at org.apache.tools.ant.Target.performTasks(Target.java:456)
        at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
        at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
        at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExe
cutor.java:41)
        at org.apache.tools.ant.Project.executeTargets(Project.java:1248)
        at org.apache.tools.ant.Main.runBuild(Main.java:851)
        at org.apache.tools.ant.Main.startAnt(Main.java:235)
        at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
        at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
Caused by: java.lang.NullPointerException
        at java.util.Properties$LineReader.readLine(Properties.java:434)
        at java.util.Properties.load0(Properties.java:353)
        at java.util.Properties.load(Properties.java:341)
        at org.cyberneko.html.HTMLEntities.load0(HTMLEntities.java:101)
        at org.cyberneko.html.HTMLEntities.<clinit>(HTMLEntities.java:53)
        ... 33 more

Total time: 2 seconds

Answer 1

如果存在任何类加载困难，我会假设会发生 NoClassDefFoundError 或 ClassNotFoundException

ExceptionInInitializerError 通常不应该引起注意，因为它只表示“嘿，程序员，初始化 block 内发生了异常”

有关初始化 block 的更多信息 here

因此，处理 NPE 将解决该问题，但不幸的是我无法访问可能导致此问题的代码。让我知道，我将编辑答案。