Question

I have a .jsp which determines what specific things a user has access to. It creates an XML file which is read into a stream by the previous jsp. How would I populate a table with the XML data which is read into a char array stream?

Answer 1

There are a lot of ways to get a HTML table out of the XML file. One of the most clean ways is to parse that XML into a collection of reuseable javabeans which you pass to the JSP, so that you can use JSTL <c:forEach> to iterate over it while rendering a HTML table. This way every layer keeps its own clear responsibility. The Java SE provided JAXB is very helpful in this.

Imagine that your XML look like this:

<data>
    <entry>
        <key>foo1</key>
        <value>bar1</value>
    </entry>
    <entry>
        <key>foo2</key>
        <value>bar2</value>
    </entry>
    <entry>
        <key>foo3</key>
        <value>bar3</value>
    </entry>
</data>

Then you can create a JAXB javabean as follows:

@XmlRootElement
public class Data {

    @XmlElement(name="entry")
    private List<Entry> entries;

    public List<Entry> getEntries() {
        return entries;
    }

    public static class Entry {

        @XmlElement
        private String key;

        @XmlElement
        private String value;

        public String getKey() {
            return key;
        }

        public String getValue() {
            return value;
        }

    }

}

Then you can transform it into a List<Entry> as follows:

List<Entry> entries = JAXBContext.newInstance(Data.class).createUnmarshaller().unmarshal(inputStream).getEntries();

Then you can let your servlet (or JSP? :/ ) store it in the request scope before forwarding the request to the JSP:

request.setAttribute("entries", entries);

Finally you can in JSP iterate over it and present it as a HTML table:

<table>
    <c:forEach items="${entries}" var="entry">
        <tr>
            <td><c:out value="${entry.key}" /></td>
            <td><c:out value="${entry.value}" /></td>
        </tr>
    </c:forEach>
</table>