How to insert values in a particular html tag using jsoup in Java?

Question

I have coded a Java program using Watcher API which checks for a folder and whenever a file is created, it adds a particular value in html tag.

This is my WATCHER API Java class:

package com.searchtechnologies;

import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardWatchEventKinds;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.util.List;

public class WatcherAPI {

    public static void main(String args[]) {
        Path myDir = Paths.get("C:/Apps/CollectionOfXMLFiles");

        try {
            WatchService watcher = myDir.getFileSystem().newWatchService();

            myDir.register(watcher, StandardWatchEventKinds.ENTRY_CREATE);

            WatchKey watckKey = watcher.take();

            List<WatchEvent<?>> events = watckKey.pollEvents();

            for (WatchEvent event : events) {
                if (event.kind() == StandardWatchEventKinds.ENTRY_CREATE) {

                    String fileName = "" + event.context();

                    HtmlParser htmlParser = new HtmlParser();
                    htmlParser.HTMLtag(fileName);
                }
            }
        }

        catch (Exception e) {
            System.out.println("Error: " + e.toString());
        }
    }
}

This is my HTMLParser.java

public void HTMLtag(String fileName) throws IOException {

        File file = new File("firstpage.html");
        Document doc = Jsoup.parse(file, "UTF-8");

        fileName = fileName.substring(0, fileName.length() - 4);
        String collection = fileName;

        doc.select("select").first().children().first()
                .before("<option value=" + collection + ">" + collection + "</option");

        PrintWriter writer = new PrintWriter("firstpage.html");
        writer.write(doc.toString());
        writer.close();

    }

It is appending the name of file in this tag:

<td valign="middle"><select name="site">
<option value="collection">collection</option>

Suppose if the name of my file is default_collection.xml, my java program extract the name of the xml file which is default_collection and adds this in my html file:

<td valign="middle"><select name="site">
    <option value="default_collection">default_collection</option>

But instead of adding it one time, my java program is adding the collection twice:

<td valign="middle"><select name="site">
        <option value="default_collection">default_collection</option>
        <option value="default_collection">default_collection</option>

I am not sure what the problem is. Any help would be appreciated.

Answer 1

You should use prepend instead, it is more appropriate in your case

Add the supplied HTML to the start of each matched element's inner HTML.

The code this then:

doc.select("select")
    .prepend("<option value=" + collection + ">" + collection + "</option");

You should also try to be as accurate as you can in your CSS selector to prevent unexpected match. Here for example your selector could be table tr td select