JXMLWhois: Quick Guide to Domain WHOIS Lookup with Java XMLWHOIS lookup remains a fundamental tool for domain management, security research, and IT administration. JXMLWhois is a Java-based approach that combines WHOIS queries with XML processing, enabling developers to retrieve, parse, and manipulate WHOIS data in structured form. This guide covers what JXMLWhois is, why you might use it, how to perform WHOIS lookups in Java, how to convert WHOIS output into XML, best practices, example code, error handling, and tips for production use.
What is JXMLWhois?
JXMLWhois refers to the concept of performing WHOIS queries from Java applications and converting the raw WHOIS text responses into an XML representation for easier parsing, storage, and integration. There isn’t a single official library named exactly “JXMLWhois” widely standardized; rather, JXMLWhois summarizes a pattern: use Java networking or a WHOIS client library to fetch WHOIS records, then transform that data into structured XML using Java XML APIs (DOM, SAX, StAX, or JAXB) or third-party libraries.
Why convert WHOIS data to XML?
- Structured data: WHOIS responses are free-form text and vary by registrar/registry. XML imposes structure, making automated processing reliable.
- Interoperability: Many tools and systems accept XML input, simplifying integration with existing workflows.
- Validation: XML schemas (XSD) can validate expected fields and formats.
- Search & storage: XML is easier to index and store in XML-aware databases or to convert to JSON for NoSQL systems.
Core components of a JXMLWhois solution
- WHOIS client: code that opens TCP connections to WHOIS servers (typically port 43) or uses existing WHOIS APIs.
- Response normalizer: cleans and segments raw WHOIS output.
- Parser/mapper: extracts fields (registrant, registration dates, name servers, status, contacts) using regex or rule-based parsing.
- XML generator: maps extracted fields into an XML document using Java APIs.
- Optional: caching, rate-limiting, and multi-server handling for robustness.
Basic WHOIS lookup in Java
Below is a concise example showing how to connect to a WHOIS server and retrieve a raw response. This example is synchronous and minimal for clarity.
import java.io.*; import java.net.Socket; import java.nio.charset.StandardCharsets; public class WhoisLookup { public static String queryWhois(String host, String query) throws IOException { try (Socket socket = new Socket(host, 43); OutputStream out = socket.getOutputStream(); InputStream in = socket.getInputStream(); BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8)); BufferedReader reader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8))) { writer.write(query + " "); writer.flush(); StringBuilder sb = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { sb.append(line).append(" "); } return sb.toString(); } } public static void main(String[] args) throws IOException { String whoisServer = "whois.verisign-grs.com"; // for .com/.net String domain = "example.com"; String response = queryWhois(whoisServer, domain); System.out.println(response); } } Notes:
- Different TLDs use different WHOIS servers; some require referral queries (querying registry then registrar).
- Consider character encoding and line endings when processing responses.
Parsing WHOIS output
WHOIS responses are heterogeneous. A pragmatic approach:
- Identify common labels (Registrar:, Creation Date:, Name Server:, etc.)
- Use regex patterns to extract values.
- Handle multiple occurrences (e.g., multiple Name Server lines).
- Treat unknown blocks as raw text to store in XML
nodes.
Example Java regex extraction snippet:
import java.util.*; import java.util.regex.*; public class WhoisParser { public static Map<String, List<String>> parse(String whoisText) { Map<String, List<String>> map = new LinkedHashMap<>(); Pattern p = Pattern.compile("(?m)^(Registrar|Creation Date|Registry Expiry Date|Name Server|Registrant Email):\s*(.+)$"); Matcher m = p.matcher(whoisText); while (m.find()) { String key = m.group(1).trim(); String val = m.group(2).trim(); map.computeIfAbsent(key, k -> new ArrayList<>()).add(val); } return map; } } Generating XML from parsed data
Use standard Java XML APIs. JAXB is convenient for binding objects to XML; for custom XML structure, DOM/StAX works well.
Simple DOM example:
import org.w3c.dom.*; import javax.xml.parsers.*; import javax.xml.transform.*; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import java.util.*; public class WhoisToXml { public static Document buildXml(Map<String, List<String>> data) throws Exception { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.newDocument(); Element root = doc.createElement("whois"); doc.appendChild(root); for (Map.Entry<String, List<String>> e : data.entrySet()) { Element field = doc.createElement(e.getKey().replaceAll("\s+","_").toLowerCase()); for (String v : e.getValue()) { Element item = doc.createElement("value"); item.appendChild(doc.createTextNode(v)); field.appendChild(item); } root.appendChild(field); } return doc; } public static void printXml(Document doc) throws Exception { Transformer t = TransformerFactory.newInstance().newTransformer(); t.setOutputProperty(OutputKeys.INDENT, "yes"); t.transform(new DOMSource(doc), new StreamResult(System.out)); } } Example end-to-end flow
- Query appropriate WHOIS server (handle referrals).
- Normalize response (remove non-UTF bytes, unify line endings).
- Parse with regex rules and fallback raw block capture.
- Map to Java objects or a Map.
- Serialize to XML (optionally validate with XSD).
- Store or convert XML to JSON for downstream systems.
Handling registrar referrals, RDAP, and rate limits
- Some registries return a referral to a registrar WHOIS server; perform the second query.
- RDAP (Registration Data Access Protocol) is a JSON-based modern alternative to WHOIS. Consider using RDAP where available; it provides structured data natively.
- Respect rate limits and robots policies. Implement client-side throttling, exponential backoff, and caching.
- Use WHOIS services or APIs (whoisxmlapi, RDAP endpoints) if you prefer managed solutions.
Error handling and robustness
- Timeouts: set socket and read timeouts.
- Encoding: detect and handle non-UTF responses.
- Missing fields: allow optional fields and preserve raw blocks.
- Parallel queries: limit concurrency to avoid IP bans.
- Logging: record queries and responses for debugging, but avoid storing sensitive personal data.
Sample XML output (illustrative)
<?xml version="1.0" encoding="UTF-8"?> <whois> <registrar> <value>NameCheap, Inc.</value> </registrar> <creation_date> <value>2005-08-14T04:00:00Z</value> </creation_date> <name_server> <value>ns1.example.com</value> <value>ns2.example.com</value> </name_server> <raw> <value>Full original WHOIS response here...</value> </raw> </whois> Best practices
- Prefer RDAP for registries that support it; use WHOIS for legacy compatibility.
- Build tolerant parsers: WHOIS formats change frequently.
- Normalize dates to ISO 8601.
- Separate parsing rules per TLD if you need high accuracy.
- Cache results and implement rate limiting.
- Consider privacy laws (GDPR) affecting availability of WHOIS data; some fields may be redacted.
Libraries and tools to consider
- Apache Commons Net — includes a basic WHOIS client.
- Jackson/Gson — for RDAP JSON handling.
- JAXB / Jackson XML / DOM / StAX — for XML generation.
- Third-party WHOIS APIs — managed services with rate limits and licensing.
Conclusion
JXMLWhois — the practice of performing WHOIS lookups in Java and converting results into XML — helps operationalize domain data for integrations, storage, and automation. Use robust parsing strategies, prefer RDAP when possible, and implement rate limiting and error handling to build a reliable service. The examples above provide a practical starting point to implement a JXMLWhois pipeline in your Java projects.
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