Question

I need to send a HTTP GET/POST request to an external API which returns XML data and then parse this data. Does an API for this exist in JSP?

If I use that code inside a class and use a method of it in JSP, will there be any problems?

Answer 1

You can use URLConnection to send a HTTP request and get the HTTP response as an InputStream. You can use JAXB to unmarshal an InputStream containing a XML document into a javabean instance which follows the XML structure.

Imagine that the XML response look like this,

<data>
    <foo>fooValue</foo>
    <bar>barValue</bar>
</data>

and your JAXB javabean look like this,

@XmlRootElement
public class Data {

    @XmlElement
    private String foo;

    @XmlElement
    private String bar;

    // Getters/setters.
}

then you can unmarshal it something like as follows:

InputStream input = new URL("http://example.com/data.xml").openStream();
Data data = (Data) JAXBContext.newInstance(Data.class).createUnmarshaller().unmarshal(input);
String foo = data.getFoo(); // fooValue
// ...

As with every other line of Java code in JSP, doing this in a JSP file instead of a normal Java class doesn’t necessarily cause technical problems, but it may end up in maintenance nightmare.