在自动化测试中常常会用到截图功能。最近用了一下selenium-webdriver的截图功能还算不错，可以截取页面全图，不管页面有多长。
下面的代码演示了如何使用webdriver进行截图：
import java.io.File;
import java.io.IOException;
import org.apache.commons.io.FileUtils;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
public class ShotScreen {
/**
* @author gongjf
* @throws IOException
* @throws InterruptedException
*/
public static void main(String[] args) throws IOException, InterruptedException {
System.setProperty("webdriver.firefox.bin","D:\\Program Files\\Mozilla Firefox\\firefox.exe");
WebDriver dr = new FirefoxDriver();
dr.get("http://www.51.com");
//这里等待页面加载完成
Thread.sleep(5000);
//下面代码是得到截图并保存在D盘下
File screenShotFile = ((TakesScreenshot)dr).getScreenshotAs(OutputType.FILE);
FileUtils.copyFile(screenShotFile, new File("D:/test.png"));}}
看了一下OutputType接口和TakesScreenshot接口，吐槽一下，貌似这两个接口不是同一个开发写的或者注释没有更新怎么的。在OutputType里面的注释说：
/**
* Defines the output type for a screenshot. See org.openqa.selenium.Screenshot for usage and
* examples.
...
然后在那找了半天的org.openqa.selenium.Screenshot 接口，晕，后来想应该是org.openqa.selenium.TakesScreenshot。
在TakesScreenshot里有如下注释：
/**
* Capture the screenshot and store it in the specified location.
*
* <p>For WebDriver extending TakesScreenshot, this makes a best effort
* depending on the browser to return the following in order of preference:
* <ul>
* <li>Entire page</li>
* <li>Current window</li>
* <li>Visible portion of the current frame</li>
* <li>The screenshot of the entire display containing the browser</li>
* </ul>
*
* <p><span style="color: #ff0000;">For WebElement extending TakesScreenshot, this makes a best effort
* depending on the browser to return the following in order of preference:
* - The entire content of the HTML element
* - The visisble portion of the HTML element</span>
*
* @param <X> Return type for getScreenshotAs.
* @param target target type, @see OutputType
* @return Object in which is stored information about the screenshot.
* @throws WebDriverException on failure.
*/
试了一下截取Webelement最终发现WebElement接口没有实现这个类。搞了半天也只是会了截取页面的全图。截取当前的frame也截取的页面全图。难道这个功能没有完善，好吧，这样说自我安慰一下。
selenium-webdriver 面向接口编程，找一个需要的功能还真是挺难的。
