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Get attribute values from all elements

Code:
Document doc = Jsoup.connect("things.com").get();
Elements jpgs = doc.select("img[src$=.jpg]");
String links = jpgs.attr("src");
System.out.print("all: " + jpgs);
System.out.print("src: " + links);
Output:
all:
<img alt="Apple" src="apple.jpg">
<img alt="Cat" src="cat.jpg">
<img alt="Boat" src="boat.jpg">
src: apple.jpg
Jsoup gave the attribute value for first element. How can I get the others (cat.jpg and boat.jpg)?
Thank you.

You loop through links and get it from each one via Element#attr, since Elements#attr (note the s) says:
Get an attribute value from the first matched element that has the attribute.
(My emphasis.)
So for instance:
for (Element e : jpgs) {
// use e.attr("src") here
}
Using Java 8's new Stream stuff, you can probably get a List<String> of them if you like:
List<String> links = jpgs.stream<Element>()
.map(element -> element.attr("src"))
.collect(Collectors.toList());
...but my Java 8 streams-fu is very weak, so that may not be quite right. Yeah, that isn't right. But that's the general idea.
The boring old-fashioned way is:
List<String> links = new ArrayList<String>(links.size());
for (Element e : jpgs) {
srcs.add(e.attr("src"));
}

Elements#attr will only return the first match.
Elements#attr Source Code
public String attr(String attributeKey) {
for (Element element : this) {
if (element.hasAttr(attributeKey))
return element.attr(attributeKey);
}
return "";
}
Solution
To obtain the result you want, you should loop over your Elements
for (Element e : jpgs) {
System.out.println(e.attr("src"));
}

how to extract email id using jsoup?

Elements elements = doc.select("span.st");
for (Element e : elements) {
out.println("<p>Text : " + e.text()+"</p>");
}
Element e contains text with some email id in it. How to extract the maild id from it. I have seen the Jsoup API doc which provides :matches(regex), but I didn't understand how to use it. I'm trying to use
^[a-zA-Z0-9_!#$%&’*+/=?`{|}~^.-]+#[a-zA-Z0-9.-]+$
which I found while googling.
Thank in advance for your help.

:matches(regex) is useful if you want to find something based on a specified regex (e.g. find all nodes that contain email).
I think this is not what you want. Instead, you need to extract the email from e.text() using regex. In your case:
Elements elements = doc.select("span.st");
for (Element e : elements) {
out.println("<p>Text : " + e.text()+"</p>");
out.println(extractEmail(e.text()));
}
// ...
public static String extractEmail(String str) {
Matcher m = Pattern.compile("[a-zA-Z0-9_.+-]+#[a-zA-Z0-9-]+\\.[a-zA-Z0- 9-.]+").matcher(str);
while (m.find()) {
return m.group();
}
return null;
}

Element id in the loop (JSOUP)

Here is my code:
Element current = doc.select("tr[class=row]").get(5);
for (Element td : current.children()) {
System.out.println(td.text());
}
How can I get an Element id in the loop?
Thanks!

In HTML id is a normal attribute, so you can simply call td.attr("id"):
Element current = doc.select("tr.row").get(5);
for (Element td : current.children()) {
System.out.println(td.attr("id"));
}
Note that there is also a selector for classes: tr.row.
JSoup supports many of the CSS selectors, so this could be rewritten with a single selector:
Elements elements = doc.select("tr.row:nth-of-type(6) > td");
for (Element element : elements) {
System.out.println(element.id());
}

Retrieving Reviews from Amazon using JSoup

I'm using JSoup to retrive reviews from a particular webpage in Amazon and what I have now is this:
Document doc = Jsoup.connect("http://www.amazon.com/Presto-06006-Kitchen-Electric-Multi-Cooker/product-reviews/B002JM202I/ref=sr_1_2_cm_cr_acr_txt?ie=UTF8&showViewpoints=1").get();
String title = doc.title();
Element reviews = doc.getElementById("productReviews");
System.out.println(reviews);
This gives me the block of html which has the reviews but I want only the text without all the tags div etc. I want to then write all this information into a file. How can I do this? Thanks!

Use text() method
System.out.println(reviews.text());

While text() will get you a bunch of text, you'll want to first use jsoup's select(...) methods to subdivide the problem into individual review elements. I'll give you the first big division, but it will be up to you to subdivide it further:
public static List<Element> getReviewList(Element reviews) {
List<Element> revList = new ArrayList<Element>();
Elements eles = reviews.select("div[style=margin-left:0.5em;]");
for (Element element : eles) {
revList.add(element);
}
return revList;
}
If you analyze each element, you should see how amazon further subdivides the information held including the title of the review, the date of the review and the body of the text it holds.

Jsoup: Optimal way of checking whether a <div> has an ID

I am able to iterate through all div elements in a document, using getElementsByTag("div").
Now I want to build a list of only div elements that have the attribute "id" (i.e. div elements with attribute "class" shouldn't be in the list).
Intuitively, I was thinking of checking something like this:
if (divElement.attr("id") != "")
add_to_list(divElement);
Is my approach correct at all?
Is there a more optimal way of testing for having the "id" attribute? (the above uses string comparison for every element in the DOM document)

You can do it like this:
Elements divsWithId = doc.select("div[id]");
for(Element element : divsWithId){
// do something
}
Reference:
JSoup > Selector Syntax

Try this:
var all_divs = document.getElementsByTagName("div");
var divs_with_id = [];
for (var i = 0; i < all_divs.length; i++)
if (all_divs[i].hasAttribute("id"))
divs_with_id.push(all_divs[i]);