如何使用HtmlUnit加载ajax？

Question

import java.io.IOException;
import java.net.MalformedURLException;
import java.util.List;

import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlAnchor;
import com.gargoylesoftware.htmlunit.html.HtmlButton;
import com.gargoylesoftware.htmlunit.html.HtmlForm;
import com.gargoylesoftware.htmlunit.html.HtmlPage;
import com.gargoylesoftware.htmlunit.html.HtmlTextInput;

public class YoutubeBot {
private static final String YOUTUBE = "http://www.youtube.com";

public static void main(String[] args) throws FailingHttpStatusCodeException, MalformedURLException, IOException {
    WebClient webClient = new WebClient();
    webClient.setThrowExceptionOnScriptError(false);

    // This is equivalent to typing youtube.com to the adress bar of browser
    HtmlPage currentPage = webClient.getPage("http://www.youtube.com/results?search_type=videos&search_query=official+music+video&search_sort=video_date_uploaded&suggested_categories=10%2C24&uni=3");

    // Get form where submit button is located
    HtmlForm searchForm = (HtmlForm) currentPage.getElementById("masthead-search");

    // Get the input field.
    HtmlTextInput searchInput = (HtmlTextInput) currentPage.getElementById("masthead-search-term");
    // Insert the search term.
    searchInput.setText("java");

    // Workaround: create a 'fake' button and add it to the form.
    HtmlButton submitButton = (HtmlButton) currentPage.createElement("button");
    submitButton.setAttribute("type", "submit");
    searchForm.appendChild(submitButton);

    //Workaround: use the reference to the button to submit the form. 
    HtmlPage newPage = submitButton.click();

    //Find all links on page with given class
    final List<HtmlAnchor> listLinks = (List<HtmlAnchor>) currentPage.getByXPath("//a[@class='ux-thumb-wrap result-item-thumb']");      

    //Print all links to console
    for (int i=0; i<listLinks.size(); i++)
        System.out.println(YOUTUBE + listLinks.get(i).getAttribute("href"));

    }
}

此代码正常工作,但我只想按照上传日期对youtube剪辑进行排序.如何使用HtmlUnit执行此操作？我必须点击过滤器,这应该通过ajax请求加载内容然后我应该点击"上传日期"链接.我只是不知道这第一步,加载ajax内容.这可能与HtmlUnit一起使用吗？

Answer 1

这是一种方法：

1. 按照您在上一个问题中所做的那样搜索该页面。
2. search-lego-refinements按 id选择块。
3. 使用 XPath 导航到 URL（//ul/li/a当您从上一个 id 开始时）。
4. 单击选定的链接。

以下代码示例展示了如何完成它：

import java.io.IOException;
import java.net.MalformedURLException;
import java.util.List;

import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlAnchor;
import com.gargoylesoftware.htmlunit.html.HtmlButton;
import com.gargoylesoftware.htmlunit.html.HtmlElement;
import com.gargoylesoftware.htmlunit.html.HtmlForm;
import com.gargoylesoftware.htmlunit.html.HtmlPage;
import com.gargoylesoftware.htmlunit.html.HtmlTextInput;

public class YoutubeBot {
   private static final String YOUTUBE = "http://www.youtube.com";

   @SuppressWarnings("unchecked")
   public static void main(String[] args) throws FailingHttpStatusCodeException, MalformedURLException, IOException {
      WebClient webClient = new WebClient();
      webClient.setThrowExceptionOnScriptError(false);

      // This is equivalent to typing youtube.com to the adress bar of browser
      HtmlPage currentPage = webClient.getPage(YOUTUBE);

      // Get form where submit button is located
      HtmlForm searchForm = (HtmlForm) currentPage.getElementById("masthead-search");

      // Get the input field
      HtmlTextInput searchInput = (HtmlTextInput) currentPage.getElementById("masthead-search-term");

      // Insert the search term
      searchInput.setText("java");

      // Workaround: create a 'fake' button and add it to the form
      HtmlButton submitButton = (HtmlButton) currentPage.createElement("button");
      submitButton.setAttribute("type", "submit");
      searchForm.appendChild(submitButton);

      // Workaround: use the reference to the button to submit the form.
      currentPage = submitButton.click();

      // Get the div containing the filters
      HtmlElement filterDiv = currentPage.getElementById("search-lego-refinements");

      // Select the first link from the filter block (Upload date)
      HtmlAnchor sortByDateLink = ((List<HtmlAnchor>) filterDiv.getByXPath("//ul/li/a")).get(0);

      // Click the 'Upload date' link
      currentPage = sortByDateLink.click();

      System.out.println(currentPage.asText());
   }
}

您也可以浏览正确的查询 URL ( http://www.youtube.com/results?search_type=videos&search_query=nyan+cat&search_sort=video_date_uploaded)。

但随后您必须对搜索参数进行编码（+例如用空格替换）。