那些遇到过的问题

使用 HtmlUnit 执行 javascript 时出错

rah*_*ver 3 javascript java google-chrome htmlunit

我正在尝试在以下 URL 上执行 JavaScript：http://steamcommunity.com/id/bobcatchris/inventory#730。我可以使用 google chrome 通过按 ctrl+shift+j 打开控制台并粘贴以下脚本来完成此操作：

var list = []; 
var size = Object.keys(g_ActiveInventory.rgInventory).size();    
var counter = 0;
while (counter < size) {
 list.push(g_ActiveInventory.rgInventory[Object.keys(g_ActiveInventory.rgInventory)[counter]].market_name);
 counter +=1;
}
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它返回： 150 然后在下一行中，我写：>list 它返回一个长度为 150 的数组。

当我尝试这样做时HtmlUnit：

 public static void main(String[] args) throws IOException {
        WebClient webClient=new WebClient(BrowserVersion.FIREFOX_17);
        HtmlPage page=webClient.getPage("http://steamcommunity.com/id/bobcatchris/inventory#730");
        String script="var list = [];\n" +
                "\n" +
                "\n" +
                "var size = Object.keys(g_ActiveInventory.rgInventory).size();\n" +
                "\n" +
                "\n" +
                "\n" +
                "var counter = 0;\n" +
                "\n" +
                "while (counter < size) {\n" +
                " list.push(g_ActiveInventory.rgInventory[Object.keys(g_ActiveInventory.rgInventory)[counter]].market_name);\n" +
                " counter +=1;\n" +
                "}";
        Object result = page.executeJavaScript(script).getJavaScriptResult();
        System.out.println(result);
    }
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我收到以下异常：

Exception in thread "main" ======= EXCEPTION START ========
EcmaError: lineNumber=[4] column=[0] lineSource=[<no source>] name=[TypeError] sourceName=[injected script] message=[TypeError: Expected argument of type object, but instead had type object (injected script#4)]
com.gargoylesoftware.htmlunit.ScriptException: TypeError: Expected argument of type object, but instead had type object (injected script#4)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:684)
    at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:602)
    at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:507)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:570)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:545)
    at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScriptIfPossible(HtmlPage.java:959)
    at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScript(HtmlPage.java:927)
    at Scraper.main(Scraper.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: net.sourceforge.htmlunit.corejs.javascript.EcmaError: TypeError: Expected argument of type object, but instead had type object (injected script#4)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3603)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3587)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.typeError(ScriptRuntime.java:3608)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.typeError1(ScriptRuntime.java:3618)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptableObject.ensureScriptable(ScriptableObject.java:2095)
    at net.sourceforge.htmlunit.corejs.javascript.NativeObject.execIdCall(NativeObject.java:287)
    at net.sourceforge.htmlunit.corejs.javascript.IdFunctionObject.call(IdFunctionObject.java:89)
    at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpretLoop(Interpreter.java:1531)
    at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpret(Interpreter.java:798)
    at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:105)
    at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.doTopCall(ContextFactory.java:405)
    at com.gargoylesoftware.htmlunit.javascript.HtmlUnitContextFactory.doTopCall(HtmlUnitContextFactory.java:309)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3031)
    at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.exec(InterpretedFunction.java:115)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$3.doRun(JavaScriptEngine.java:561)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:669)
    ... 12 more
Enclosed exception: 
net.sourceforge.htmlunit.corejs.javascript.EcmaError: TypeError: Expected argument of type object, but instead had type object (injected script#4)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3603)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3587)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.typeError(ScriptRuntime.java:3608)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.typeError1(ScriptRuntime.java:3618)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptableObject.ensureScriptable(ScriptableObject.java:2095)
    at net.sourceforge.htmlunit.corejs.javascript.NativeObject.execIdCall(NativeObject.java:287)
    at net.sourceforge.htmlunit.corejs.javascript.IdFunctionObject.call(IdFunctionObject.java:89)
    at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpretLoop(Interpreter.java:1531)
    at script(injected script:4)
    at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpret(Interpreter.java:798)
    at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:105)
    at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.doTopCall(ContextFactory.java:405)
    at com.gargoylesoftware.htmlunit.javascript.HtmlUnitContextFactory.doTopCall(HtmlUnitContextFactory.java:309)
    at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3031)
    at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.exec(InterpretedFunction.java:115)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$3.doRun(JavaScriptEngine.java:561)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:669)
    at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:602)
    at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:507)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:570)
    at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.execute(JavaScriptEngine.java:545)
    at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScriptIfPossible(HtmlPage.java:959)
    at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScript(HtmlPage.java:927)
    at Scraper.main(Scraper.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
======= EXCEPTION END ========
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引起异常的行是：

Object result = page.executeJavaScript(script).getJavaScriptResult();
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那么我应该如何像从 google chrome 控制台一样从 HtmlUnit 执行这个脚本呢？

Pop*_*ibo 5

这些是您的框架javascript转换为的脚本错误Java exceptions。

\n\n

那是因为您没有明确地将setThrowExceptionOnScriptError您的选项设置WebClient为false。

\n\n

除非 中绝对没有错误js，否则始终将此值设置为 false 很有用，除非它会干扰您正在寻找的结果。

\n\n

通常，这些是我webclient在处理js和ajax通过时的设置HtmlUnit。

\n\n
final WebClient webClient = new WebClient(BrowserVersion.FIREFOX_17,\n                PROXY_HOST, PROXY_PORT);\n\nWebRequest request = new WebRequest(new URL(\n                "http://steamcommunity.com/id/bobcatchris/inventory#730"));\n\nwebClient.getOptions().setThrowExceptionOnScriptError(false);\nwebClient.setJavaScriptTimeout(10000);\nwebClient.getOptions().setJavaScriptEnabled(true);\nwebClient.setAjaxController(new NicelyResynchronizingAjaxController());\nwebClient.getOptions().setTimeout(10000);\n\nHtmlPage page = webClient.getPage(request);\n\n          String script="var list = [];\\n" +\n                    "\\n" +\n                    "\\n" +\n                    "var size = Object.keys(g_ActiveInventory.rgInventory).size();\\n" +\n                    "\\n" +\n                    "\\n" +\n                    "\\n" +\n                    "var counter = 0;\\n" +\n                    "\\n" +\n                    "while (counter < size) {\\n" +\n                    " list.push(g_ActiveInventory.rgInventory[Object.keys(g_ActiveInventory.rgInventory)[counter]].market_name);\\n" +\n                    " counter +=1;\\n" +\n                    "}";\n            Object result = page.executeJavaScript(script).getJavaScriptResult();\n            System.out.println(result);\n
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如果我尝试您的代码，使用上述设置，我会150.0打印到控制台，我认为它按预期工作。

\n\n

编辑：

\n\n

遍历整个数组list：

\n\n
String script="var list = [];\\n" +\n                    "\\n" +\n                    "\\n" +\n                    "var size = Object.keys(g_ActiveInventory.rgInventory).size();\\n" +\n                    "\\n" +\n                    "\\n" +\n                    "\\n" +\n                    "var counter = 0;\\n" +\n                    "\\n" +\n                    "while (counter < size) {\\n" +\n                    " list.push(g_ActiveInventory.rgInventory[Object.keys(g_ActiveInventory.rgInventory)[counter]].market_name);\\n" +\n                    " counter +=1;\\n" +\n                    "}"\n                    + "list";\n\n            Object result = page.executeJavaScript(script).getJavaScriptResult();\n            if (result instanceof NativeArray) {\n                for (Object obj : (NativeArray)result) {\n                    System.out.println(obj);    \n                }\n\n            }\n
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上面，我已将js包含列表更改为返回参数并迭代NativeArray以获取每个元素。

\n\n

输出：

\n\n
P2000 | Scorpion (Factory New)\nAK-47 | Black Laminate (Field-Tested)\n\xe2\x98\x85 StatTrak\xe2\x84\xa2 Karambit | Case Hardened (Minimal Wear)\nCS:GO Case Key\nCS:GO Case Key\n
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您可以在此处的常见问题解答中阅读有关其 ajax 设置的更多内容。

\n

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