jsoup.element.select（）抛出什么异常？

Question

I wanted to execute the following code (Jsoup):

    Elements lessondata = td.select(" > table.container > tbody > tr > td > span.nobr");
    for (Element lesson : lessondata) {
    System.out.println("Lesson...");
        }

But only if it is possible to select this > table.container > tbody> tr > td > span.nobr. Sometimes, the website doesn't have these tags. Therefore, I wanted to put this piece of code in a 'try' piece, and catch the exception if the selection I want to make is impossible. But now I need to know: what exception does element.select() throw if it is impossible to select the given path?

I would appreciate your help.

Answer 1

You don't need to catch a Exception. According to the Documentation

@return elements that match the query (empty if none match)

just check if lessondata.isEmpty()

Answer 2

It doesn't throw any exception and returns an empty elements list.

Use isEmpty() or size() to check the returned list.

Elements lessondata = td.select(
                      " > table.container > tbody > tr > td > span.nobr");
if (!lessondata.isEmpty()) {
  for (Element lesson : lessondata) {
    System.out.println("Lesson...");
  }
}

JavaDoc: http://jsoup.org/apidocs/org/jsoup/nodes/Element.html#select(java.lang.String)