[3]Selenium学习系列---- 一个简单的Selenium Java 工程

在前面的一个章节，笔者介绍了[1]Selenium学习系列---- Selenium IDE工具的安装，顺便告诉大家一个小秘密，其实Selenium IDE还可以录制网页的操作过程，并导出成C#，Java，Python，Ruby等各种各样形式的代码。笔者就以Selenium IDE录制并导出Java代码为例子，给大家演示一个Selenium Hello World项目。

1. 打开Selenium IDE,并输入一个目标网站地址并开启录制功能。本文以Tomcat的官方网站为例子，http://tomcat.apache.org/

2. 上面红线框内的准备就绪后，点击Selenium IDE右边录制按钮，开始录制。

3. 这个时候在http://tomcat.apache.org/网站上的任意操作都会被Selenium IDE记录下来。

4. 选择导出代码，并取名为ApacheWebSiteTest.java

5. 打开Eclipse，新建一个Maven的工程，下面是Maven的pom.xml

	4.0.0
	com.sample.selenium
	selenium-learn
	0.0.1-SNAPSHOT
	selenium-learn
	selenium-learn1
	
		
			central
			Maven Repository Switchboard
			default
			http://repo1.maven.org/maven2
			
				false
			
		
	
	
		
			junit
			junit
			4.12
		
		
			org.seleniumhq.selenium
			selenium-java
			3.0.1
		
	

6. 把上面的 ApacheWebSiteTest.java复制到这个maven项目中。

package com.example.tests;

import java.util.regex.Pattern;
import java.util.concurrent.TimeUnit;
import org.junit.*;
import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.*;
import org.openqa.selenium.*;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.Select;

public class ApacheWebSiteTest {
  private WebDriver driver;
  private String baseUrl;
  private boolean acceptNextAlert = true;
  private StringBuffer verificationErrors = new StringBuffer();

  @Before
  public void setUp() throws Exception {
    driver = new FirefoxDriver();
    baseUrl = "http://tomcat.apache.org/";
    driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
  }

  @Test
  public void testApacheWebSite() throws Exception {
    driver.get(baseUrl + "/");
    driver.findElement(By.linkText("Home")).click();
    driver.findElement(By.linkText("PoweredBy")).click();
    driver.findElement(By.linkText("Tomcat Connectors")).click();
    driver.findElement(By.linkText("Tomcat 8.5")).click();
    driver.findElement(By.xpath("(//a[contains(text(),'Tomcat Native')])[2]")).click();
    driver.findElement(By.linkText("archive download site")).click();
    driver.findElement(By.linkText("Tomcat Native")).click();
  }

  @After
  public void tearDown() throws Exception {
    driver.quit();
    String verificationErrorString = verificationErrors.toString();
    if (!"".equals(verificationErrorString)) {
      fail(verificationErrorString);
    }
  }

  private boolean isElementPresent(By by) {
    try {
      driver.findElement(by);
      return true;
    } catch (NoSuchElementException e) {
      return false;
    }
  }

  private boolean isAlertPresent() {
    try {
      driver.switchTo().alert();
      return true;
    } catch (NoAlertPresentException e) {
      return false;
    }
  }

  private String closeAlertAndGetItsText() {
    try {
      Alert alert = driver.switchTo().alert();
      String alertText = alert.getText();
      if (acceptNextAlert) {
        alert.accept();
      } else {
        alert.dismiss();
      }
      return alertText;
    } finally {
      acceptNextAlert = true;
    }
  }
}

7. 注意上面的代码跑起来是会抛出下面的异常的

java.lang.IllegalStateException: The path to the driver executable must be set by the webdriver.gecko.driver system property; for more information, see https://github.com/mozilla/geckodriver. The latest version can be downloaded from https://github.com/mozilla/geckodriver/releases
	at com.google.common.base.Preconditions.checkState(Preconditions.java:199)
	at org.openqa.selenium.remote.service.DriverService.findExecutable(DriverService.java:109)
	at org.openqa.selenium.firefox.GeckoDriverService.access$000(GeckoDriverService.java:37)
	at org.openqa.selenium.firefox.GeckoDriverService$Builder.findDefaultExecutable(GeckoDriverService.java:95)
	at org.openqa.selenium.remote.service.DriverService$Builder.build(DriverService.java:296)
	at org.openqa.selenium.firefox.FirefoxDriver.createCommandExecutor(FirefoxDriver.java:277)
	at org.openqa.selenium.firefox.FirefoxDriver.(FirefoxDriver.java:247)
	at org.openqa.selenium.firefox.FirefoxDriver.(FirefoxDriver.java:242)
	at org.openqa.selenium.firefox.FirefoxDriver.(FirefoxDriver.java:238)
	at org.openqa.selenium.firefox.FirefoxDriver.(FirefoxDriver.java:127)
	at com.example.tests.ApacheWebSiteTest.setUp(ApacheWebSiteTest.java:20)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

java.lang.NullPointerException
	at com.example.tests.ApacheWebSiteTest.tearDown(ApacheWebSiteTest.java:39)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:33)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

8. 解决方法是，针对Firefox浏览器，需要下载geckodriver.exe web驱动（webDriver，网上可以搜索geckodriver.exe 的下载）并在setup（）方法中设置下面的类似代码：

 @Before
  public void setUp() throws Exception {
    System.setProperty("webdriver.gecko.driver","D:/drivers/geckodriver.exe");
    driver = new FirefoxDriver();
    baseUrl = "http://tomcat.apache.org/";
    driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
  }

恭喜你，第一个Selenium Hello World的例子就这样写成了，是不是很简单啊！！！！

对了，对于上面7中遇到的问题，还有另外一种更智能和方便的解决方案（前提是读者的网络足够强大能访问这些网站，具体原因，你懂的！）

在Pom.xml文件的依赖中加入

    io.github.bonigarcia
    webdrivermanager
    1.4.10

然后在每次新建WebDriver对象之前，调用下面的方法。比如在setup（）方法中。

MarionetteDriverManager.getInstance().setup();

如果读者对于后面的一种方式感兴趣的话，可以自己测试验证。