java code for Html Parse Servlet

import java.io.IOException;
import java.io.PrintWriter;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.MalformedURLException;

import javax.servlet.*;
import javax.servlet.http.*;

import javax.swing.text.html.HTMLEditorKit.ParserCallback;
import javax.swing.text.MutableAttributeSet;
import javax.swing.text.html.parser.ParserDelegator;

public class HtmlParseServlet extends HttpServlet {

private static final String BASE_URL = "http://finance.yahoo.com/q?d=t&s=";

private ParserDelegator htmlParser = null;

private MyParserCallback callback = null;

private String htmlText = "";

private boolean lastTradeFlag = false;

private boolean boldFlag = false;

private float stockVal = 0f;

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, java.io.IOException {

//set the MIME type of the response, "text/html"
response.setContentType("text/html");

//use a PrintWriter send text data to the client who has requested the
// servlet
java.io.PrintWriter out = response.getWriter();

//Begin assembling the HTML content
out.println("");

out.println("");
out.println("

Please submit a new valid stock symbol

");

//make sure method="post" so that the servlet service method
//calls doPost in the response to this form submit
out.println("

+ request.getContextPath() + "/stockservlet\" >");

out.println("");
out.println("

"); out.println("Stock symbol:	"); out.println(""); out.println("
"); out.println("

");
out.println("");

} //end doGet

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws java.io.IOException {

String symbol;//this will hold the stock symbol
float price;

symbol = request.getParameter("symbol");

boolean isValid = (symbol == null || symbol.length() < 1) ? false
: true;

//set the MIME type of the response, "text/html"
response.setContentType("text/html");

//use a PrintWriter send text data to the client who has requested the
// servlet
java.io.PrintWriter out = response.getWriter();

//Begin assembling the HTML content
out.println("");
out.println("");

if (!isValid) {
out
.println("

Sorry, the stock symbol parameter was either empty or null

");
} else {

out.println("

Here is the latest value of " + symbol + "

");

price = getLatestPrice(symbol);
//price < 1 ? "The symbol is probably invalid." :
out.println((price == 0 ? "The symbol is probably invalid." : ""
+ price));

}

out.println("");

}// doPost

private float getLatestPrice(String symbol) throws IOException,
MalformedURLException {

BufferedReader webPageStream = null;
URL stockSite = new URL(BASE_URL + symbol);
System.out.println(BASE_URL + symbol);
webPageStream = new BufferedReader(new InputStreamReader(stockSite
.openStream()));

htmlParser = new ParserDelegator();

callback = new MyParserCallback();

synchronized (htmlParser) {//the code is designed to make calling
// parse() thread-safe

htmlParser.parse(webPageStream, callback, true);
}

return stockVal;

}//getLatestPrice

class MyParserCallback extends ParserCallback {

public MyParserCallback() {

if (stockVal != 0)
stockVal = 0f;

}

public void handleStartTag(javax.swing.text.html.HTML.Tag t,
MutableAttributeSet a, int pos) {

if (lastTradeFlag && (t == javax.swing.text.html.HTML.Tag.B)) {

boldFlag = true;
}

}//handleStartTag

public void handleText(char[] data, int pos) {

htmlText = new String(data);

if (htmlText.indexOf("No such ticker symbol.") != -1) {

throw new IllegalStateException(
"Invalid ticker symbol in handleText() method.");

} else if (htmlText.equals("Last Trade:")) {

lastTradeFlag = true;

} else if (boldFlag) {

try {

stockVal = new Float(htmlText).floatValue();

} catch (NumberFormatException ne) {

try {

// tease out any commas in the number using NumberFormat

java.text.NumberFormat nf = java.text.NumberFormat
.getInstance();

Double f = (Double) nf.parse(htmlText);

stockVal = (float) f.doubleValue();

} catch (java.text.ParseException pe) {

throw new IllegalStateException("The extracted text "
+ htmlText + " cannot be parsed as a number!");

}
}
lastTradeFlag = false;
boldFlag = false;

}//if

} //handleText
}//MyParserCallback
}//HttpServlet