How to handle file download popup using Selenium WebDriver?

I have written a code to download an excel file, it is working, but it stops as soon as the popup appears. Automatically it should download the file and store in specified location, which is not happening now. Please anyone help in finding a solution for this problem

FirefoxProfile profile = new FirefoxProfile();
WebDriver driver = new FirefoxDriver(profile); 


profile.setPreference("browser.helperapps.neverAsk.saveToDisk" , "text/csv"); 
profile.setPreference("browser.download.folderList", 2); 
profile.setPreference("browser.download.dir","e:\\SampleExcel"); 

driver.get("http://url");
driver.findElement(By.name("email")).sendKeys("[email protected]");
driver.findElement(By.name("pass")).sendKeys("abc");
driver.findElement(By.id("edit-submit")).click();
driver.findElement(By.id("toolbar-link-admin-config")).click();
driver.findElement(By.linkText("Reports")).click();
driver.findElement(By.xpath("//input[@value='5']")).click();
driver.findElement(By.id("edit-submit")).click();

Try below code

FirefoxProfile profile = new FirefoxProfile();
        String path = "D:\\Downloads_sel";
        profile.setPreference("browser.download.folderList", 2);
        profile.setPreference("browser.download.dir", path);
        profile.setPreference("browser.download.alertOnEXEOpen", false);
        profile.setPreference("browser.helperApps.neverAsksaveToDisk", "application/x-msexcel,application/excel,application/x-excel,application/excel,application/x-excel,application/excel,application/vnd.ms-excel,application/x-excel,application/x-msexcel");
        profile.setPreference("browser.download.manager.showWhenStarting", false);
        profile.setPreference("browser.download.manager.focusWhenStarting", false);
        profile.setPreference("browser.helperApps.alwaysAsk.force", false);
        profile.setPreference("browser.download.manager.alertOnEXEOpen", false);
        profile.setPreference("browser.download.manager.closeWhenDone", false);
        profile.setPreference("browser.download.manager.showAlertOnComplete", false);
        profile.setPreference("browser.download.manager.useWindow", false);
        profile.setPreference("browser.download.manager.showWhenStarting", false);
        profile.setPreference("services.sync.prefs.sync.browser.download.manager.showWhenStarting", false);
        profile.setPreference("pdfjs.disabled", true);

        WebDriver driver = new FirefoxDriver(profile);

For complete MIME types list follow the link: http://qaautomationworld.blogspot.in/2014/02/file-downlaoding-using-selenium.html

Try to use this code:

FirefoxProfile profile = new FirefoxProfile();
WebDriver driver = new FirefoxDriver(profile); 

profile.setPreference("browser.helperApps.neverAsk.saveToDisk" , "application/octet-stream;application/csv;text/csv;application/vnd.ms-excel;"); 
profile.setPreference("browser.helperApps.alwaysAsk.force", false);
profile.setPreference("browser.download.manager.showWhenStarting",false);
profile.setPreference("browser.download.folderList", 2); 
profile.setPreference("browser.download.dir","e:\\SampleExcel");