Java Servlet

What is Java Servlet?

• A Servlet is a java based server side web technology. It is a java class that serves a client request and receives a response from the server.

Adding a Servlet

• Servlet is a class with a “java” extension:– Ex: FVServlet.java

• It must belong to a package:– Ex: ServletPackage

• FVServlet.java

Servlet Methods:doGet() and doPost()

processRequest Method:

1. doGet and doPost methods now call processRequest method to handle the http requests.2. These methods use the same request and response objects as JSP.

protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter();

Example: Future Value Calculator:Requesting FVServlet servlet

<form name="fvForm" method="post" action="FVServlet"> Enter present value: <input type="text" name="PV" value="" /><br><br> Select interest rate: <select name="Rate"> <option value=.04>4%</option> <option value=.05>5%</option> <option value=.06>6%</option> <option value=.07>7%</option> <option value=.08>8%</option> </select><br><br> Select year: <br> <input type="radio" name="Year" value="10" />10-year<br> <input type="radio" name="Year" value="15" />15-year<br> <input type="radio" name="Year" value="30" />30-year<br><br> <br> <input type="submit" value="ComputeFVJSP" name="btnCompute"/> </form>

FVServlet

protected void processRequest(HttpServletRequest request, HttpServletResponse response) String myPV, myRate, myYear,qString; myPV=request.getParameter("PV"); myRate=request.getParameter("Rate"); myYear=request.getParameter("Year"); double FV, PV, Rate, Year; PV=Double.parseDouble(myPV); Rate=Double.parseDouble(myRate); Year=Double.parseDouble(myYear); FV=PV*Math.pow(1+Rate,Year); out.println("FutureValue is:"+ FV);

Straight Line Depreciation Table

Straight Line Depreciation Table <form name="depForm" method="post" action="depTableServlet"> Enter Property Value: <input type="text" name="pValue" value="" /><br> Enter Property Life: <input type="text" name="pLife" value="" /><br> <input type="submit" value="Show Table" name="btnShowTable" /> </form>

String strValue, strLife; strValue=request.getParameter("pValue"); strLife=request.getParameter("pLife"); double value, life, depreciation,totalDepreciation=0; value=Double.parseDouble(strValue); life=Double.parseDouble(strLife); NumberFormat nf = NumberFormat.getCurrencyInstance(); out.println("Straight Line Depreciation Table" + "<br>"); out.println("Property Value: <input type='text' name='pValue' value='" + nf.format(value) + "' /><br>"); out.println("Property Life: <input type='text' name='pLife' value='" + life + "' /><br>"); depreciation=value/life; totalDepreciation=depreciation; out.println( "<table border='1' width='400' cellspacing=1>"); out.println("<thead> <tr> <th>Year</th> <th>Value at BeginYr</th>"); out.println("<th>Dep During Yr</th> <th>Total to EndOfYr</th></tr> </thead>"); out.println("<tbody>"); for (int count = 1; count <= life; count++) { out.write("<tr>"); out.write(" <td width='10%'>" + count + "</td>"); out.write(" <td width='30%'>" + nf.format(value) + "</td>"); out.write(" <td width='30%'>" + nf.format(depreciation) + "</td>"); out.write(" <td width='30%'>" + nf.format(totalDepreciation) + "</td>"); value -= depreciation; totalDepreciation+=depreciation; }

Creating a Java Database with NetBeans

• Tutorial:– http://

netbeans.org/kb/docs/ide/java-db.html#starting

JDBC

• http://docs.oracle.com/javase/tutorial/jdbc/basics/index.html