java - 使用WebDriver JS Executor执行.js文件 --> 空指针异常

Question

我正在尝试实现一个我在网上找到的脚本，该脚本可以自动将 jQuery 加载到当前没有它们的网站中。我正在使用 Selenium Webdriver 的 JS Executor 功能；但是，它不断返回空指针异常。我试图到处寻找答案，但似乎无法理解发生了什么。给出了什么？

/** Browser automation driver for this test instance. */
private WebDriver driver;

/** JavaScript Executor for this test instance. */
private JavascriptExecutor js = (JavascriptExecutor) driver;

//...Firefox browser initialized here

 public void JQuerify(final String Url){
    ReporterNG.log("Opening a webpage at: " + Url);
    driver.get(Url);

    ReporterNG.log("Converting JS file to a String");

        String jQueryLoader = getLoadJQuery();

        // give jQuery time to load asynchronously
        driver.manage().timeouts().setScriptTimeout(10, TimeUnit.SECONDS);

        js.executeAsyncScript(jQueryLoader);
        //THE PROBLEM ALWAYS OCCURS WITH THIS ^^^^^

        ReporterNG.log("jQuery loaded!");
        //THIS NEVER PRINTS OUT DUE TO THE ERROR ^^^^
}

 /** dynamically load jQuery */
public static String getLoadJQuery(){
    String LoadJQuery = "(function(jqueryUrl, callback) {\n" +
            "if (typeof jqueryUrl != 'string') {" +
            "jqueryUrl = 'https://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js';\n" +
            "}\n" +
            "if (typeof jQuery == 'undefined') {\n" +
            "var script = document.createElement('script');\n" +
            "var head = document.getElementsByTagName('head')[0];\n" +
            "var done = false;\n" +
            "script.onload = script.onreadystatechange = (function() {\n" +
            "if (!done && (!this.readyState || this.readyState == 'loaded'\n" +
            "|| this.readyState == 'complete')) {\n" +
            "done = true;\n" +
            "script.onload = script.onreadystatechange = null;\n" +
            "head.removeChild(script);\n" +
            "callback();\n" +
            "}\n" +
            "});\n" +
            "script.src = jqueryUrl;\n" +
            "head.appendChild(script);\n" +
            "}\n" +
            "else {\n" +
            "callback();\n" +
            "}\n" +
            "})(arguments[0], arguments[arguments.length - 1]);\n";
    return LoadJQuery;
}

任何帮助将不胜感激，因为我在 JS Executor 的其他类似应用程序中遇到了同样的问题。谢谢!

Answer 1

使 JavascriptExecutor 实例成为该方​​法的本地实例。

JavascriptExecutor js = (JavascriptExecutor) driver;
// give jQuery time to load asynchronously
driver.manage().timeouts().setScriptTimeout(10, TimeUnit.SECONDS);
js.executeAsyncScript(jQueryLoader);