运行网络驱动程序脚本时随机发生IndexOutOfBounds异常

Question

I am working on selenium webdriver script on a webpage: http://data.worldbank.org/income-level/HIC

Consider this implementation:

public void retrieveCountryData() throws Exception{
        Thread.sleep(2000);
        WebDriverWait wait = new WebDriverWait(driver, 60); 
        List<WebElement> countryNames = driver.findElements(By.cssSelector("a[href*='/country/']"));
        for(int i =76;i<countryNames.size();i++){
            List<WebElement> countryLinks = driver.findElements(By.cssSelector("a[href*='/country/']"));
            wait.until(ExpectedConditions.visibilityOfElementLocated(By.cssSelector("a[href*='/country/']")));
            Thread.sleep(3000);
            WebElement elem =countryLinks.get(i);
            JavascriptExecutor js = (JavascriptExecutor)driver;
            js.executeScript("window.scrollTo(" + elem.getLocation().x + "," +(elem.getLocation().y- 100) + ");");

            String countryText = elem.getText();
            System.out.println("The Country is: "+ countryText);
            elem.click();
            wait.until(ExpectedConditions.visibilityOfElementLocated(countryDetailVerify));
            Thread.sleep(2000);
            driver.navigate().back();
}

This script runs correctly sometimes, and at other times, it gives IndexOutOfBounds Excption. I have run this script 10 times, and 6 times it gave that exception, and 4 times it runs its whole process.

Following is the stack-trace of the exception:

java.lang.IndexOutOfBoundsException: Index: 77, Size: 0
    at java.util.ArrayList.rangeCheck(Unknown Source)
    at java.util.ArrayList.get(Unknown Source)
    at pageObjects.WorldBankData.retrieveCountryData(WorldBankData.java:172)
    at testCases.SampleTest.getCTex(SampleTest.java:35)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:85)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:639)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:816)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1124)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:108)
    at org.testng.TestRunner.privateRun(TestRunner.java:774)
    at org.testng.TestRunner.run(TestRunner.java:624)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:359)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:354)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:312)
    at org.testng.SuiteRunner.run(SuiteRunner.java:261)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1215)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1140)
    at org.testng.TestNG.run(TestNG.java:1048)
    at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:112)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:205)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:176)

at pageObjects.WorldBankData.retrieveCountryData(WorldBankData.java:172) refers to WebElement elem =countryLinks.get(i); in my script.

Can someone tell me why am I facing this issue?

Answer 1

It's hard to tell what you're trying to accomplish. I cleaned up your method and took care of the index out of bounds exception. The exception was happening because countryLinks.get(i) would get called when i was equal to a value greater than the total number of countryLinks . So if there were only 77 countries, when countryLinks.get(78) was called because i=78 then it would throw the exception.

@Test
public void retrieveCountryData() throws Exception {
    WebDriver driver = new FirefoxDriver();
    WebDriverWait wait = new WebDriverWait(driver, 15);
    By countrySelector = By.cssSelector("a[href*='/country/']");
    By countryDetailVerify = By.cssSelector("countryDetailVerify?");

    driver.get("http://data.worldbank.org/income-level/HIC");
    List<WebElement> countryNames = driver.findElements(countrySelector);

    for (int i = 76; i < countryNames.size() - 1; i++) {
        List<WebElement> countryLinks = driver.findElements(countrySelector);
        wait.until(ExpectedConditions.visibilityOfAllElementsLocatedBy(countrySelector));

        WebElement elem = countryLinks.get(i);
        JavascriptExecutor js = (JavascriptExecutor) driver;
        js.executeScript("window.scrollTo(" + elem.getLocation().x + "," + (elem.getLocation().y - 100) + ");");

        String countryText = elem.getText();
        System.out.println("The Country is: "+ countryText);
        elem.click();
        wait.until(ExpectedConditions.visibilityOfElementLocated(countryDetailVerify));

        driver.navigate().back();
    }
}