java - 尝试在 Selenium Java 中制作屏幕截图时出现 NPE

Question

我尝试了各种方法，但仍然得到 NPE。请参阅下面的代码片段。

TestBase.class

public WebDriver initializeDriver() { // nothing special }

public void takeScreenshot(String testResult) {
    try {
      File screenshotFile = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
      FileUtils.copyFile(screenshotFile, new File(
        "//Users//roman//Desktop//MainProject//SeleniumJava//ScreenshotsFailure//"
        + testResult + "_" + "screenshot.png"));

      //
      // System.getProperty("user.dir")

      log.info("Screenshot of " + testResult + "'s failure has been created successfully");
    } catch (IOException e) {
      e.printStackTrace();
      log.error("Screenshot of " + testResult + "'s failure has not been created");
    }
  }

Listeners.class

public class Listeners implements ITestListener {
  TestBase testBase = new TestBase();
  Date currentDate;

  @Override
  public void onTestFailure(ITestResult iTestResult) {
        currentDate = new Date();
        testBase.takeScreenshot(iTestResult.getName() + "_" + currentDate.getTime());
  }

HomePageTest.class

          @Test
          void my() {
            Assert.assertEquals(driver.getTitle(), "adb"); 
// intentionally cause False to take a screenshot of this failure
          }

所以 NPE 发生的是这两行:

  File screenshotFile = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);

和

testBase.takeScreenshot(iTestResult.getName() + "_" + currentDate.getTime());

如何解决这个问题？非常感谢!

Answer 1

NPE 不能出现在两行中。总是只有一行抛出异常。打印并显示异常的堆栈跟踪。

我假设 driver 和 iTestResult 或 currentDate 为空，无论出于何种原因。您可以在使用它们之前插入一条日志消息来打印它们的值。

您还可以插入换行符，然后堆栈跟踪会准确地告诉您哪个部分有空指针:

testBase.takeScreenshot(
      iTestResult.getName() + "_" + 
      currentDate.getTime());