HtmlUnit HtmlSubmitInput.click() 结果"Incorrect URL"更正为 "cgi-bin" 然后导致 UnknownHostException

Question

我正在尝试编写一个应该访问此网站的小机器人http://lsa.colorado.edu/cgi-bin/LSA-pairwise.html，在文本区域中输入一些文本，然后按提交按钮从提交中获取结果页面。这是一个语言学项目。然而，当我点击HtmlSubmitInput按钮时，返回的URL似乎格式错误，因为IncorrectnessListenerImpl通知我：

Apr 10, 2016 2:38:35 PM com.gargoylesoftware.htmlunit.IncorrectnessListenerImpl notify
WARNUNG: Incorrect URL "http:/cgi-bin/LSA-pairwise-x.html" has been corrected

URL应该是

http://lsa.colorado.edu/cgi-bin/LSA-pairwise-x.html

这会导致以下堆栈跟踪（由于长度而缩短）：

Exception in thread "main" java.lang.RuntimeException: java.net.UnknownHostException: cgi-bin: unknown error
    at com.gargoylesoftware.htmlunit.WebClient.download(WebClient.java:2078)
    at com.gargoylesoftware.htmlunit.html.HtmlForm.submit(HtmlForm.java:141)
    at com.gargoylesoftware.htmlunit.html.HtmlSubmitInput.doClickStateUpdate(HtmlSubmitInput.java:90)
    at com.gargoylesoftware.htmlunit.html.DomElement.click(DomElement.java:795)
    at com.gargoylesoftware.htmlunit.html.DomElement.click(DomElement.java:742)
    at com.gargoylesoftware.htmlunit.html.DomElement.click(DomElement.java:689)
    at LSABot.submitInput(LSABot.java:30)
    at Start.main(Start.java:8)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
 [...]

我的猜测是HtmlUnit试图修复URL，但这只会导致"cgi-bin"，当然这是错误的。我找了一遍又一遍，但没有找到任何与我的问题相关的东西。

我的LSABot类：

public class LSABot {
    final WebClient webClient;
    private HtmlPage mainPg, rsltPg;
    private HtmlForm htmlForm;
    private HtmlTextArea txtA;
    private HtmlSubmitInput submitBt;
    public LSABot () throws Exception {
        this.webClient = new WebClient(BrowserVersion.CHROME);
        this.webClient.getOptions().setJavaScriptEnabled(true);
        this.mainPg = this.webClient.getPage("http://lsa.colorado.edu/cgi-bin/LSA-pairwise.html");
        this.htmlForm = this.mainPg.getForms().get(0);
        this.txtA = this.htmlForm.getTextAreaByName("txt1");
        this.submitBt = this.htmlForm.getInputByValue("Submit Texts");
    }
    public void submitInput(String input) {
        this.txtA.setText(input);
        try {
            this.rsltPg = this.submitBt.click();
            this.webClient.waitForBackgroundJavaScript(30*1000);
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }

Answer 1

错误来自表单的html内容。action属性应该是http://lsa.colorado.edu/cgi-bin/LSA-pairwise-x.html而不是http:/cgi-bin/LSA-pairwise-x.html。

试试这个代码，它应该工作：

LogFactory.getFactory().setAttribute("org.apache.commons.logging.Log", "org.apache.commons.logging.impl.NoOpLog");
java.util.logging.Logger.getLogger("com.gargoylesoftware").setLevel(Level.OFF); 
java.util.logging.Logger.getLogger("org.apache.commons.httpclient").setLevel(Level.OFF);
WebClient client = new WebClient(BrowserVersion.CHROME);
client.getOptions().setJavaScriptEnabled(true);
client.getOptions().setThrowExceptionOnScriptError(false);
client.getOptions().setThrowExceptionOnFailingStatusCode(false);
String url = "http://lsa.colorado.edu/cgi-bin/LSA-pairwise.html";
final HtmlPage page = client.getPage(url);
HtmlForm htmlForm = page.getForms().get(0);
HtmlTextArea txtA = htmlForm.getTextAreaByName("txt1");
txtA.setText("hello");
HtmlSubmitInput submitBt = htmlForm.getInputByValue("Submit Texts");
// change the form action attribute to the correct one  
htmlForm.setAttribute("action", "http://lsa.colorado.edu/cgi-bin/LSA-pairwise-x.html");
HtmlPage page2 = submitBt.click();
System.out.println(page2.asText());