极其简单的代码无法在HtmlUnit中运行

时间：2011-08-26 06:36:49

标签： java html htmlunit jstack

我正在使用HtmlUnit 2.9（本月发布的稳定版本）。你知道为什么以下代码不起作用吗？

public class Main {

    public static void main(String[] args) {
        WebClient webClient = new WebClient(BrowserVersion.FIREFOX_3_6);
        webClient.setCssEnabled(true);
        webClient.setCssErrorHandler(new SilentCssErrorHandler());
        webClient.setThrowExceptionOnFailingStatusCode(false);
        webClient.setThrowExceptionOnScriptError(false);
        webClient.setRedirectEnabled(false);
        webClient.setAppletEnabled(false);
        webClient.setJavaScriptEnabled(false);
        webClient.setPopupBlockerEnabled(true);
        webClient.setTimeout(60000);
        webClient.setPrintContentOnFailingStatusCode(false);

        System.out.println("This is printed on screen");
        try {
            webClient.getPage("http://www.2cash.info/index.php");
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("This is NEVER printed on screen");
    }
}

我也在添加jstack的结果。请注意，我已经标记了一个不断重复的部分：

2011-08-26 03:15:45
Full thread dump Java HotSpot(TM) Server VM (20.1-b02 mixed mode):

"Attach Listener" daemon prio=10 tid=0x09520400 nid=0x5363 waiting on condition [0x00000000]
   java.lang.Thread.State: RUNNABLE

"JS executor for com.gargoylesoftware.htmlunit.WebClient@a7c45e" daemon prio=10 tid=0x6feb7400 nid=0x5356 waiting on condition [0x6fcfe000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
    at java.lang.Thread.sleep(Native Method)
    at com.gargoylesoftware.htmlunit.javascript.background.JavaScriptExecutor.run(JavaScriptExecutor.java:166)
    at java.lang.Thread.run(Thread.java:662)

"Low Memory Detector" daemon prio=10 tid=0x70204c00 nid=0x5352 runnable [0x00000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" daemon prio=10 tid=0x70202800 nid=0x5351 runnable [0x00000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" daemon prio=10 tid=0x70200800 nid=0x5350 waiting on condition [0x00000000]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" daemon prio=10 tid=0x09514c00 nid=0x534f runnable [0x00000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" daemon prio=10 tid=0x09503400 nid=0x534e in Object.wait() [0x70798000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x76af2ff0> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
    - locked <0x76af2ff0> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
    at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)

"Reference Handler" daemon prio=10 tid=0x09501c00 nid=0x534d in Object.wait() [0x707e9000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x7675cc58> (a java.lang.ref.Reference$Lock)
    at java.lang.Object.wait(Object.java:485)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
    - locked <0x7675cc58> (a java.lang.ref.Reference$Lock)

"main" prio=10 tid=0x09482400 nid=0x5349 runnable [0xb6c34000]
   java.lang.Thread.State: RUNNABLE
    at net.sourceforge.htmlunit.corejs.javascript.ScriptableObject.getSlot(ScriptableObject.java:2603)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptableObject.defineProperty(ScriptableObject.java:1699)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.configureConstantsPropertiesAndFunctions(JavaScriptEngine.java:350)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.configureClass(JavaScriptEngine.java:330)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.init(JavaScriptEngine.java:199)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.access$000(JavaScriptEngine.java:79)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$1.run(JavaScriptEngine.java:146)
    at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:537)
    at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:538)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.initialize(JavaScriptEngine.java:157)
    at com.gargoylesoftware.htmlunit.WebClient.initialize(WebClient.java:1141)
    at com.gargoylesoftware.htmlunit.WebWindowImpl.setEnclosedPage(WebWindowImpl.java:109)
    at com.gargoylesoftware.htmlunit.html.FrameWindow.setEnclosedPage(FrameWindow.java:102)
    at com.gargoylesoftware.htmlunit.html.HTMLParser.parse(HTMLParser.java:200)
    at com.gargoylesoftware.htmlunit.html.HTMLParser.parseHtml(HTMLParser.java:179)
    at com.gargoylesoftware.htmlunit.DefaultPageCreator.createHtmlPage(DefaultPageCreator.java:221)
    at com.gargoylesoftware.htmlunit.DefaultPageCreator.createPage(DefaultPageCreator.java:106)
    at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseInto(WebClient.java:433)
    at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:311)
    at com.gargoylesoftware.htmlunit.html.BaseFrame.<init>(BaseFrame.java:73)
    at com.gargoylesoftware.htmlunit.html.HtmlInlineFrame.<init>(HtmlInlineFrame.java:46)
    at com.gargoylesoftware.htmlunit.html.DefaultElementFactory.createElementNS(DefaultElementFactory.java:288)
    at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.startElement(HTMLParser.java:506)
    at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown Source)
    at org.cyberneko.html.HTMLTagBalancer.callStartElement(HTMLTagBalancer.java:1136)
    at org.cyberneko.html.HTMLTagBalancer.startElement(HTMLTagBalancer.java:742)
    at org.cyberneko.html.filters.DefaultFilter.startElement(DefaultFilter.java:136)
    at org.cyberneko.html.filters.NamespaceBinder.startElement(NamespaceBinder.java:278)
    at org.cyberneko.html.HTMLScanner$ContentScanner.scanStartElement(HTMLScanner.java:2652)
    at org.cyberneko.html.HTMLScanner$ContentScanner.scan(HTMLScanner.java:2022)
    at org.cyberneko.html.HTMLScanner.scanDocument(HTMLScanner.java:908)
    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.parse(HTMLParser.java:789)
    at com.gargoylesoftware.htmlunit.html.HTMLParser.parse(HTMLParser.java:225)
    at com.gargoylesoftware.htmlunit.html.HTMLParser.parseHtml(HTMLParser.java:179)
    at com.gargoylesoftware.htmlunit.DefaultPageCreator.createHtmlPage(DefaultPageCreator.java:221)
    at com.gargoylesoftware.htmlunit.DefaultPageCreator.createPage(DefaultPageCreator.java:106)
    at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseInto(WebClient.java:433)
    at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:311)

    <THIS_SECTION_IS_PRINTED_AS_IF_IT_WERE_IN_A_LOOP>
    at com.gargoylesoftware.htmlunit.html.BaseFrame.loadInnerPageIfPossible(BaseFrame.java:149)
    at com.gargoylesoftware.htmlunit.html.BaseFrame.loadInnerPage(BaseFrame.java:99)
    at com.gargoylesoftware.htmlunit.html.HtmlPage.loadFrames(HtmlPage.java:1760)
    at com.gargoylesoftware.htmlunit.html.HtmlPage.initialize(HtmlPage.java:194)
    at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseInto(WebClient.java:440)
    at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:311)
    </THIS_SECTION_IS_PRINTED_AS_IF_IT_WERE_IN_A_LOOP>

    at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:311)
    at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:373)
    at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:358)
    at main.Main.<init>(Main.java:42)
    at main.Main.main(Main.java:23)

"VM Thread" prio=10 tid=0x094fe000 nid=0x534c runnable 

"GC task thread#0 (ParallelGC)" prio=10 tid=0x09489800 nid=0x534a runnable 

"GC task thread#1 (ParallelGC)" prio=10 tid=0x0948ac00 nid=0x534b runnable 

"VM Periodic Task Thread" prio=10 tid=0x70207000 nid=0x5353 waiting on condition 

JNI global references: 1234

我认为关于帧的自动加载存在某种循环。如果是这种情况，有没有办法禁用该行为来打破循环？

提前致谢！

2 个答案:

答案 0 :(得分：2)

当我在浏览器中打开此站点时，它无法完成加载页面。这可能是HtmlUnit崩溃的原因。使用Chrome和FF进行测试。

尝试加载一个更简单的网站，您可能知道此崩溃是否是网站依赖的。

答案 1 :(得分：2)

嗯，虽然这是一个可怕的解决方案（解决方法，实际上......），但我最终决定在HtmlUnit中禁用自动加载帧，正如HtmlUnit的开发者之一所建议的那样。这就是我的细节：

  1. 下载了HtmlUnit源
  2. 从here
    3. 下载了maven
  3. 对位于loadFrames()
    4. 中的HtmlPage类的htmlunit-2.9/src/main/java/com/gargoylesoftware/htmlunit/html方法的内容（方法的主体，而不是声明）进行了评论
  4. 使用以下代码编译此自定义代码跳过测试：mvn -Dmaven.test.skip=true clean compile package
  5. 新htmlunit-2.9.jar位于htmlunit-2.9/artifacts并替换了当前的htmlunit-2.9.jar库文件
  6. 此步骤可能是最精细的步骤，因为它取决于每个应用程序。但是，我会向您展示我需要对我的应用程序进行的更改。

    7. 你知道我的原始代码是怎样的（看看这个问题）。这将从页面下载所有帧和iframe。我正在添加一个示例，说明如何获取带有帧的页面，只需加载所需的帧：

    try {
    HtmlPage page = webClient.getPage("http://www.w3schools.com/HTML/tryit.asp?filename=tryhtml_noframes");
    HtmlInlineFrame frame = page.getFirstByXPath("//iframe[@name='view']");
    page = webClient.getPage(page.getFullyQualifiedUrl(frame.getSrcAttribute()));
    System.out.println(page.asXml());
} catch (Exception e) {
    e.printStackTrace();
}

    更改此库后，getPage()方法完成后，帧的内容将为空。注意它不会为null，看起来它只是返回一个空框架。我们需要做的是手动下载我们感兴趣的帧的内容，这就是我再次执行getPage()的原因。

    这就是我设法用HtmlUnit选择性地下载帧和iframe的方法。任何关于如何改进这一点的想法将不胜感激。无论如何，我希望将来会添加一些方法来禁用HtmlUnit中的帧加载，可能会添加getPage(URL url, boolean downloadFrames)之类的方法。

    希望这有助于那里的人！

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