selenium-java-Firefox 特殊异常：界面找不到元素

在selenium + Java + Firefox 的时候会出现不能通过 By.id()的方式找到界面元素，但是实际上界面上通过fireBug能够找到该元素的且唯一，为什么找不到到呢？

原因分析如下：

1.界面中不只存在一个该name或者class或者的名称的元素；

2.界面中存在iframe框架存在；

3.通过debug模式能够找到界面元素，但是run时，就找不到元素，唯一的一种解释：打开firefox，输入地址后，界面一直处于加载中，当界面未加载完成，便通过webdriver去中界面元素，当然会出现找不到的情况；解决方案：加入等待处理（等待处理方式），再做查找元素处理；thread.sleep();

调整前代码如下

package info . www . itest ;

import static org . junit . Assert .*;

import org.junit.* ;

import org.openqa.selenium.By ;

import org.openqa.selenium.WebDriver ;

import org.openqa.selenium.firefox.FirefoxDriver ;

public class CreatePost {

@Before

public void setUp () throws Exception {

}

@After

public void tearDown () throws Exception {

}

@Test

public void testLogin (){

System . setProperty ( "webdriver.firefox.bin" , "D:\\Program Files\\Mozilla Firefox\\firefox.exe" );

WebDriver dr = new FirefoxDriver ();

dr . get ( "http://www.1988.com/wordpress/wp-login.php" );

//个人地址

dr . findElement ( By . id ( "user_login" )). sendKeys ( "admin" );

dr . findElement ( By . id ( "user_pass" )). sendKeys ( "admin" );

dr . findElement ( By . id ( "wp-submit" )). click ();

assertTrue ( dr . getCurrentUrl (). contains ( "admin" ));

}

}

错误信息如下

org.openqa.selenium.NoSuchElementException: Unable to locate element: {"method":"id","selector":"user_login"}

Command duration or timeout: 29.28 seconds

For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html

Build info: version: '2.41.0', revision: '3192d8a', time: '2014-03-27 17:18:15'

System info: host: 'HS-Q0TFDE785GM3', ip: '169.254.183.27', os.name: 'Windows 7', os.arch: 'x86', os.version: '6.1', java.version: '1.6.0_16'

Session ID: c438cb88-3d6c-422d-8aca-a95f2d84bfff

Driver info: org.openqa.selenium.firefox.FirefoxDriver

Capabilities [{platform=XP, acceptSslCerts=true, javascriptEnabled=true, browserName=firefox, rotatable=false, locationContextEnabled=true, version=4.0.1, cssSelectorsEnabled=true, databaseEnabled=true, handlesAlerts=true, nativeEvents=false, webStorageEnabled=true, applicationCacheEnabled=true, takesScreenshot=true}]

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)

at java.lang.reflect.Constructor.newInstance(Constructor.java:513)

at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:193)

at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:145)

at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:595)

at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:348)

at org.openqa.selenium.remote.RemoteWebDriver.findElementById(RemoteWebDriver.java:389)

at org.openqa.selenium.By$ById.findElement(By.java:214)

at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:340)

at info.www.itest.CreatePost.testLogin(CreatePost.java:27)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)

at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)

at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)

at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)

at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)

at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)

at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)

at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)

at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)

at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)

at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)

at org.junit.runners.ParentRunner.run(ParentRunner.java:236)

调整后代码如下

package info . www . itest ;

import static org . junit . Assert .*;

import org.junit.* ;

import org.openqa.selenium.By ;

import org.openqa.selenium.WebDriver ;

import org.openqa.selenium.WebElement ;

import org.openqa.selenium.firefox.FirefoxDriver ;

public class CreatePost {

@Before

public void setUp () throws Exception {

}

@After

public void tearDown () throws Exception {

}

@Test

public void testLogin () throws InterruptedException {

System . setProperty ( "webdriver.firefox.bin" , "D:\\Program Files\\Mozilla Firefox\\firefox.exe" );

WebDriver driver = new FirefoxDriver ();

driver . get ( "http://localhost/wordpress/wp-login.php" );

System . out . println ( driver . getCurrentUrl ());

Thread . sleep ( 30000 );

WebElement elementName = driver . findElement ( By . id ( "user_login" ));

elementName . sendKeys ( "admin" );

WebElement elementPassword = driver . findElement ( By . id ( "user_pass" ));

elementPassword . sendKeys ( "admin" );

driver . findElement ( By . id ( "wp-submit" )). click ();

assertTrue ( driver . getCurrentUrl (). contains ( "admin" ));

}

}