你可以使用等待。硒中基本上有两种类型的等待

隐式等 显式等

-隐式等待

这很简单，请参阅下面的语法:

driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);

-显式等待

在此等待中显式等待或有条件等待，直到给定条件发生。

WebDriverWait wait = new WebDriverWait(driver, 40);
WebElement element = wait.until(ExpectedConditions.elementToBeClickable(By.id("someid")));

您可以使用其他属性，如visblityOf()， visblityOfElement()

对于使用java 8向前的程序员，可以使用下面的代码来使用显式等待等待页面加载。

JavascriptExecutor js = (JavascriptExecutor) driver;  
new WebDriverWait(driver, 10).until(webDriver ->
(js).executeScript("return document.readyState;").equals("complete"));

注意:在我上面的代码中使用Lambda表达式，它只在java 8的后续版本中可用。

对于使用低版本Java(即Java 8以下)的程序员，可以使用:

ExpectedCondition<Boolean> cond = new ExpectedCondition<Boolean>() {
    @Override
    public Boolean apply(WebDriver input) {
        JavascriptExecutor js = (JavascriptExecutor) driver; 
        return js.executeScript("return document.readyState;").equals("complete");
            }
        };
         
    new WebDriverWait(driver, 100).until(cond);

如果你想等待一个特定的元素加载，你可以在RenderedWebElement上使用isdisplay()方法:

// Sleep until the div we want is visible or 5 seconds is over
long end = System.currentTimeMillis() + 5000;
while (System.currentTimeMillis() < end) {
    // Browsers which render content (such as Firefox and IE) return "RenderedWebElements"
    RenderedWebElement resultsDiv = (RenderedWebElement) driver.findElement(By.className("gac_m"));

    // If results have been returned, the results are displayed in a drop down.
    if (resultsDiv.isDisplayed()) {
      break;
    }
}

(例子来自《5分钟入门指南》)

这似乎是WebDriver的一个严重限制。显然，等待一个元素并不意味着页面正在加载，特别是DOM可以完全构建(onready状态)，此时JS仍在执行，CSS和图像仍在加载。

我相信最简单的解决方案是在onload事件上设置一个JS变量，在所有东西初始化后，在Selenium中检查和等待这个JS变量。

您可以删除系统。线。添加它是为了调试目的。

WebDriver driver_;

public void waitForPageLoad() {

    Wait<WebDriver> wait = new WebDriverWait(driver_, 30);
    wait.until(new Function<WebDriver, Boolean>() {
        public Boolean apply(WebDriver driver) {
            System.out.println("Current Window State       : "
                + String.valueOf(((JavascriptExecutor) driver).executeScript("return document.readyState")));
            return String
                .valueOf(((JavascriptExecutor) driver).executeScript("return document.readyState"))
                .equals("complete");
        }
    });
}

您可以尝试这段代码，让页面完全加载，直到找到元素为止。

public void waitForBrowserToLoadCompletely() {
    String state = null;
    String oldstate = null;
    try {
        System.out.print("Waiting for browser loading to complete");

        int i = 0;
        while (i < 5) {
            Thread.sleep(1000);
            state = ((JavascriptExecutor) driver).executeScript("return document.readyState;").toString();
            System.out.print("." + Character.toUpperCase(state.charAt(0)) + ".");
            if (state.equals("interactive") || state.equals("loading"))
                break;
            /*
             * If browser in 'complete' state since last X seconds. Return.
             */

            if (i == 1 && state.equals("complete")) {
                System.out.println();
                return;
            }
            i++;
        }
        i = 0;
        oldstate = null;
        Thread.sleep(2000);

        /*
         * Now wait for state to become complete
         */
        while (true) {
            state = ((JavascriptExecutor) driver).executeScript("return document.readyState;").toString();
            System.out.print("." + state.charAt(0) + ".");
            if (state.equals("complete"))
                break;

            if (state.equals(oldstate))
                i++;
            else
                i = 0;
            /*
             * If browser state is same (loading/interactive) since last 60
             * secs. Refresh the page.
             */
            if (i == 15 && state.equals("loading")) {
                System.out.println("\nBrowser in " + state + " state since last 60 secs. So refreshing browser.");
                driver.navigate().refresh();
                System.out.print("Waiting for browser loading to complete");
                i = 0;
            } else if (i == 6 && state.equals("interactive")) {
                System.out.println(
                        "\nBrowser in " + state + " state since last 30 secs. So starting with execution.");
                return;
            }

            Thread.sleep(4000);
            oldstate = state;

        }
        System.out.println();

    } catch (InterruptedException ie) {
        ie.printStackTrace();
    }
}