如何在硒中執行js？

-1

任何人知道如何執行這個腳本js.executeScript("window.addEventListener('load',function(){document.getElementsByTagName('script')[1].src='google.com'})");

或

js.executeScript("window.load = function() 
{document.getElementsByTagName('script')[1].src='google.com'})");

這個腳本返回null。 Eclipse中說：異常線程「main」顯示java.lang.NullPointerException 在autotesting.itacademy.main（itacademy.java:58）

這裏主要的代碼是：提前

package autotesting; 

import org.openqa.selenium.JavascriptExecutor; 
import org.openqa.selenium.WebDriver; 
import java.io.IOException; 
import java.util.ArrayList; 
import java.util.List; 
import java.util.Set; 
import java.util.concurrent.TimeUnit; 

import org.apache.commons.io.FileUtils; 
import org.openqa.selenium.*; 
import org.openqa.selenium.firefox.FirefoxDriver; 
import org.openqa.selenium.logging.LogEntries; 
import org.openqa.selenium.support.ui.Select; 
import org.openqa.selenium.By; 
import org.openqa.selenium.JavascriptExecutor; 
import org.openqa.selenium.OutputType; 
import org.openqa.selenium.TakesScreenshot; 
import org.openqa.selenium.WebDriver; 
import org.openqa.selenium.WebElement; 

//for read and write from file 
import java.io.BufferedReader; 
import java.io.BufferedWriter; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileNotFoundException; 
import java.io.FileReader; 
import java.io.FileWriter; 
import java.util.Scanner; 

public class itacademy { 

    private static WebDriver driver = null; 

    public static JavascriptExecutor js = (JavascriptExecutor) driver; 

    public static void main(String[] args) throws IOException { 
     // TODO Auto-generated method stub 

     JavascriptExecutor js = (JavascriptExecutor) driver; 

     driver = new FirefoxDriver(); 
     driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS); 
     driver.manage().window().maximize();   
     driver.get("http://office.co.uk/"); 

     js.executeScript("window.addEventListener('load',function(){document.getElementsByTagName('script')[1].src='google.com'})"); 
      }}

謝謝

來源

2015-11-12 Jack

請分享您的堆棧跟蹤... – Tgsmith61591

@ Tgsmith61591異常線程「main」顯示java.lang.NullPointerException在autotesting.itacademy.main（itacademy.java:58） – Jack

@ Tgsmith61591而且這個例外在線程「主「java.lang.IllegalStateException：顯示java.lang.NullPointerException \t在autotesting.itacademy.main（itacademy.java:58） – Jack

你永遠不會初始化你的JavascriptExecutor。看看這裏，您分配driver爲空，然後嘗試將它轉換爲JavascriptExecutor，從不初始化：

private static WebDriver driver = null; // driver is null 
public static JavascriptExecutor js = (JavascriptExecutor) driver; // js is null

後來，分配js到driver和然後初始化驅動程序對象，在這裏：

JavascriptExecutor js = (JavascriptExecutor) driver; // js is null 
driver = new FirefoxDriver(); // driver is now an object

而是看你做什麼用js的時候，它仍然是空：

js.executeScript("window.addEventListener('load',function({document.getElementsByTagName('script')[1].src='google.com'})"); // It's still null here!

您需要正確初始化您的js對象。順便說一句，您已經宣佈js爲班級成員，爲什麼您立即將其重新分配給主要成員？

public static JavascriptExecutor js = (JavascriptExecutor) driver; 
JavascriptExecutor js = (JavascriptExecutor) driver; // This line is unnecessary in main

來源

2015-11-13 13:13:26 Tgsmith61591

如何在硒中執行js？

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