Selenium 同时用到firefox和ie

selenium 同一个类是需要用到firefox和ie怎么办

driver.get("http://developer.ylz.com:14072/developer/getAllApplicationByUser.html");
inputById("username", "c");
inputById("password", "a");
Selenium selenium=new WebDriverBackedSelenium(driver, "");
selenium.click("id=submit");
clickAndSwitch(By.id("submit"));
clickAndSwitch(By.linkText("修改"));
clickAndSwitch(By.id("submitButton"));

//需要用IE操作的地方调用IE：

driverIE=new InternetExplorerDriver();
driverIE.get("http://developer.ylz.com:14072/developer/getAllApplicationByUser.html");
driverIE.findElement(By.id("username")).sendKeys("c");
driverIE.findElement(By.id("password")).sendKeys("a");
driverIE.findElement(By.id("submit")).click();
driverIE.get("http://developer.ylz.com:14072/developer/updateBasic.html?application.appId=3004&applicationTmp.appTmpId=1002&application.appName=电");
driverIE.findElement(By.name("inputImgFiles")).sendKeys("G:\\工作\\民生网msw\\3rd-创建,申请应用\\图片上传测试\\pictureOfAppScreenshot\\1.png");
pause(5000L);
driverIE.findElement(By.xpath("//img[@alt='立即上传']")).click();
driverIE.findElement(By.xpath("//img[@alt='立即上传']")).click();
driverIE.close();
//然后接着用Firefox操作
inputById("","");
......