xpath locator not work as expected to locate a "<a" element with compound class name

This line will not work but I think I have used correct xpath?

driver.findElement(By.xpath("//a[contains(@class,'cke_button_bold')]")).click();

to locate a button li开发者_如何转开发ke below :

<a id="cke_73" class="cke_off cke_button_bold">

id is a dynamic number so can be used as fixed locator here. And class is a compound class which is not supported by WebDriver findElement method...

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I created simple html file and your xpath works with FirefoxDriver in WebDriver 2.1.0.
Also you can try to use

driver.findElement(By.className("cke_button_bold"))

Classname is supported by webdriver Api

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Step 1:

Find the CSS Selector

Possible CSS Selectors here:

css=a[id*='cke']

css=.cke_off cke_button_bold

The above can be used Or Already we are having the method .ClassName But for avoiding duplication of Elements and Ambiguity we can use CSS Selector.