Server-Side Scripting with Java Server Page, JSP ISYS 350
Java Website Java Tutorial: JSP, Servlet tutorial: http://docs.oracle.com/javase/tutorial/ JSP, Servlet tutorial: http://www.jsptut.com/ http://docs.oracle.com/javaee/5/tutorial/doc/bnagx.html http://www.javatpoint.com/servlet-tutorial
Java Platforms Java SE (Standard Edition) provides the core functionality of the Java programming language. It defines everything from the basic types and objects of the Java programming language to high-level classes that are used for networking, security, database access, etc. Java EE (Enterprise Edition) is built on top of the Java SE platform for developing and running large-scale, multi-tiered, scalable, reliable, and secure network applications. Java ME (Mobile Edition) provides an API and a small-footprint virtual machine for running Java programming language applications on small devices, like mobile phones.
Hyper Text Transfer Protocol: Request & Response HTTP Request Browser Web Server HTTP Response Web Application
Use JSP to Process a Form
FORM Button: Form attribute: Type = “submit” Action: Specify the URL of a program on a server or an email address to which a form’s data will be submitted. Method: Post/Get Get: the form’s data is appended to the URL specified by the Action attribute as a QueryString. Post: A preferred method for database processing. Form’s data is sent in the HTTP body. Post is the preferred method. Example: <form name="testForm" method="post" action="computeSum.jsp“> Button: Type = “submit” <input type="submit" value="ComputeSumJSP" name="btnCompute"/>
QueryString A QueryString is a set of name=value pairs appended to a target URL. It can be used to pass information from one webpage to another. To create a QueryString: Add a question mark (?) immediately after a URL. Followed by name=value pairs separated by ampersands (&). Example: <A Href=“http://my.com/Target.htm?CustID=C1&Cname=Chao”>
Data Sent with Request and Response requested URL, cookies, queryString, data from a form, etc. Response: Web page content in HTML code Cookies Etc.
Java Server Pages, JSP Java Server Pages (JSP) is a technology that lets you mix regular, static HTML with dynamically-generated HTMLrequest: JSP objects: Request object: retrieves the values that the client browser passed to the server during an HTTP request Response object: This denotes the HTTP Response data. Session: This denotes the data associated with a specific session of user. The main use of Session Objects is for maintaining states when there are multiple page requests. Out object: print, println
Methods of request Object getParameter(String name): Returns the value of a request parameter as a String, or null if the parameter does not exist. getQueryString(): Gets any query string that is part of the HTTP request URI. getCookies(): Gets the array of cookies found in this request. getRequestURI(): Gets the URI to the current JSP page. etc.
Methods of response Object addCookie(Cookie): Adds the specified cookie to the response. It can be called multiple times to set more than one cookie. sendRedirect(String): Sends a temporary redirect response to the client using the specified redirect location URL.
JSP Out Object print: The print method of out object writes the value to the output without a newline character. out.print("Welcome!!!"); out.print("To JSP Training"); Output is: Welcome!!! To JSP Training
JSP scriptlet <% %> Example: <body> <h1>Hello World!</h1> <% out.print("Welcome!!!"); out.print("To JSP Training"); %> </body> Question: How to start a new line? out.print("<br>To JSP Training");
In addition to the eight primitive data types listed above, the Java programming language also provides special support for character strings via the java.lang. String class. String s = "this is a string";.
Compute the Sum of 2 Numbers:
Form Example <body> <div>Compute the sum of two numbers</div> <form name="testForm" method="post" action="computeSum.jsp"> Enter num1: <input type="text" name="num1" value="" /><br> Enter num2: <input type="text" name="num2" value="" /><br><br> <input type="submit" value="ComputeSumJSP" name="btnCompute"/> </form> </body> Notre 1: The form has a method property nd action property. Note2: The button now is type: submit, and there is no onclick event.
Example of JSP scriptlet <% %> Compute the Sum of 2 Numbers: <body> <% String value1, value2; double n1, n2, sum; value1=request.getParameter("num1"); value2=request.getParameter("num2"); n1= Double.parseDouble(value1); n2= Double.parseDouble(value2); sum=n1+n2; out.print("The sum is:" + sum); %> </body> Note 1: Double is an object that offers the parseDouble method, not “double” data type. Note 2: “out” is an implicit object that does not need to be declared. It is already predefined .
Writing HTML code as output <body> <% String value1, value2; double n1, n2, sum; value1=request.getParameter("num1"); value2=request.getParameter("num2"); n1= Double.parseDouble(value1); n2= Double.parseDouble(value2); sum=n1+n2; out.print(" <p>Value1: <input type=‘text' name='num1' size='20' value='" + value1 + "'></p>"); out.print(" <p>Value2: <input type='text' name='num2' size='20' value='" + value2 + "'></p>"); out.print("The sum is: <input type='text' name='sum' size='20' value='" + sum + "'>" ); %> </body>
Embed JSP code in HTML Using JSP Expression: <%= %> String value1, value2; double n1, n2, sum; value1=request.getParameter("num1"); value2=request.getParameter("num2"); n1= Double.parseDouble(value1); n2= Double.parseDouble(value2); sum=n1+n2; %> <form method="POST" name="testForm" > <p>Value1: <input type="text" name="num1" size="20" value="<%=value1%>"></p> <p>Value2: <input type="text" name="num2" size="20" value="<%=value2%>"></p> <p> Sum is: <input type="text" name="num2" size="20" value="<%=sum%>"></p> </form>
Compute Future Value: Process form with various controls
Form Code <form name="fvForm" method="post" action="computeFV.jsp"> 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> <input type="submit" value="ComputeFVJSP" name="btnCompute" /> </form>
JSP Code Example <body> <% String myPV, myRate, myYear; 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.print("FutureValue is:"+ FV); %>
CheckBox Example: value attribute A checkbox in a form: <input type="checkbox" name=“NPF" value="ON" /> Non-Profit In JSP program: myChk=request.getParameter(“NPF"); if (myChk=="ON") out.print("Checkbox is on!"); else out.print(“Checkbox is off!");
Depreciation Table Straight Line Depreciation Table <form name="depForm" method="post" action="createDepTable.jsp"> Enter Property Value: <input type="text" name="pValue" value="" /><br> Enter Property Life: <input type="text" name="pLife" value="" /><br> <input type="submit" value="ShowTable JSP" name="btnShowTable" /> </form>
Output
<% 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); depreciation=value/life; NumberFormat nf = NumberFormat.getCurrencyInstance(); out.print("Stright Line Depreciation Table" + "<br>"); out.print("Property Value: <input type='text' name='pValue' value='" + nf.format(value) + "' /><br>"); out.print("Property Life: <input type='text' name='pLife' value='" + life + "' /><br>"); totalDepreciation=0; out.print( "<table border='1' width='400' cellspacing=1>"); out.print("<thead> <tr> <th>Year</th> <th>Value at BeginYr</th>"); out.print("<th>Dep During Yr</th> <th>Total to EndOfYr</th></tr> </thead>"); out.print("<tbody>"); for (int count = 1; count <= life; count++) { out.print("<tr>"); out.print(" <td >" + count + "</td>"); out.print(" <td >" + nf.format(value) + "</td>"); out.print(" <td>" + nf.format(depreciation) + "</td>"); totalDepreciation+=depreciation; out.print(" <td>" + nf.format(totalDepreciation) + "</td>"); value -= depreciation; } %>
Number to Currency Format Import class: <%@page import="java.text.NumberFormat"%> Define a format: NumberFormat nf = NumberFormat.getCurrencyInstance(); Convert: Example: Display payment with currency format: nf.format(payment)
Using JSP Expression <body> <% 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(); depreciation=value/life; totalDepreciation=depreciation; %> <p>Straight Line Depreciation Table</p> <p>Property Value: <input type='text' name='pValue' value='<%=nf.format(value)%>' /></p> <p>Property Life: <input type='text' name='pLife' value='<%=life%>'/></p> <table border='1' width='400' cellspacing=1> <thead> <tr> <th>Year</th> <th>Value at BeginYr</th> <th>Dep During Yr</th> <th>Total to EndOfYr</th> </tr> </thead> <tbody> for (int count = 1; count <= life; count++) { <tr> <td><%=count%></td> <td><%=nf.format(value)%></td> <td><%=nf.format(depreciation)%></td> <td><%=nf.format(totalDepreciation)%></td> </tr> value -= depreciation; totalDepreciation+=depreciation; } </table> </body>
Display Percentage Format: Import class: <%@page import="java. text Display Percentage Format: Import class: <%@page import="java.text.NumberFormat"%> double rate = 0.05267; NumberFormat pFormat = NumberFormat.getPercentInstance(); pFormat.setMinimumFractionDigits(2); out.println("Percent format: " + pFormat.format(rate));
Use Client-Side Validating and Sumbit Validated Form <script > function Validating(){ var Valid; Valid=true; if (document.fvForm.PV.value=="") {Valid=false;} if (Valid==false){alert("Cannot contain blank");} else {document.fvForm.submit();} } </script> Note: Must use a standard button, not submit button: <input type="button" value="ComputeFVJSP" name="btnCompute" onclick="Validating()"/>
Date Class Example: Display Current Date Time Import java.util.Date <%@page import="java.util.Date"%> Define a Date type variable: Date currentDate = new Date(); Display in textbox using JSP expression: <p>The time is: <input type="text" name="num2" size="20" value="<%=currentDate%>"></p>
Code Example <%@page import="java.util.Date"%> <%@page contentType="text/html" pageEncoding="UTF-8"%> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>JSP Page</title> </head> <body> <% Date currentDate = new Date(); %> <p>The time is: <input type="text" name="num2" size="20" value="<%=currentDate%>"></p> </body> </html>
Date to Date Format Import class: Define a format: <%@page import="java.text.SimpleDateFormat"%> Define a format: SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yy"); Convert: Example: Display a date with date format: String displayDate = formatter.format(currentDate);
Java Array Examples of declaring an array: int[] anArray = new int[10]; 10 elements index from 0 to 9 double[] anArrayOfDoubles = new double[10]; String[] anArrayOfStrings = new String[10]; int[] anArray = { 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000};
Creating a listbox of rates double[] rates= {0.03,0.04,0.05,0.06,0.07}; String[] displays={"3%","4%","5%","6%","7%"}; out.println( "Select interest rate: <select name='Rate'>"); for (int i = 0; i <= rates.length-1; i++) { out.print("<option value='" + rates[i] + "'>" + displays[i] + "</option>"); } out.print( "</select><br><br>");
Compute Future Value: Process form with controls Created Using JSP Code: Note this page is a jsp page
JSP code to create the form <form name="fvForm" method="post" action="computeFV.jsp"> Enter present value: <input type="text" name="PV" value="" /><br><br> <% double[] rates= {0.03,0.04,0.05,0.06,0.07}; String[] displays={"3%","4%","5%","6%","7%"}; out.print( "Select interest rate: <select name='Rate'>"); for (int i = 0; i <= rates.length-1; i++) { out.print("<option value='" + rates[i] + "'>" + displays[i] + "</option>"); } out.print( "</select><br><br>"); double[] yearValues= {10,15,30}; String[] yearLabels={"10-year","15-year","30-year"}; out.print( "Select year:<br><br>"); for (int i = 0; i <= yearValues.length-1; i++) out.print("<input type='radio' name='Year' value='" + yearValues[i] + "'/>" + yearLabels[i] + "<br><br>"); %> <input type="submit" value="ComputeFVJSP" name="btnCompute" /> </form>
JSP Code to process the form <body> <% String myPV, myRate, myYear; 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.print("FutureValue is:"+ FV); %>
Show selected rate and checked radio button checked box: “selected” radiobutton: “checked” <form name="fvForm"> Enter present value: <input type="text" name="PV" value="<%=PV%>" /><br><br> <% double[] rates= {0.03,0.04,0.05,0.06,0.07}; String[] displays={"3%","4%","5%","6%","7%"}; out.print( "Select interest rate: <select name='Rate'>"); for (int i = 0; i <= rates.length-1; i++) { if(rates[i]==Rate) out.print("<option value='" + rates[i] + "' selected>" + displays[i] + "</option>"); else out.print("<option value='" + rates[i] + "'>" + displays[i] + "</option>"); } out.print( "</select><br><br>"); double[] yearValues= {10,15,30}; String[] yearLabels={"10-year","15-year","30-year"}; out.print( "Select year:<br><br>"); for (int i = 0; i <= yearValues.length-1; i++) if(yearValues[i]==Year) out.print("<input type='radio' name='Year' value='" + yearValues[i] + "' checked/>" + yearLabels[i] + "<br><br>"); out.print("<input type='radio' name='Year' value='" + yearValues[i] + "'/>" + yearLabels[i] + "<br><br>"); %> FV: <input type="text" name="FV" value="<%=FV%>" /><br><br> <input type="submit" value="ComputeFVJSP" name="btnCompute" /> </form>
Cookie Cookie is a small data file added by a website to reside in user’s system. Define a cookie: new Cookie(“Key”, “value”); Ex. Cookie cookieCID = new Cookie ("cookieCID",CID); Write a cookie: response.addCookie(cookieCID);
Example: </form> <% String CID, Cname; <form name="custForm" action="addCookie.jsp" method="POST"> Enter CID: <input type="text" name="CID" value="" /><br><br> Enter Cname: <input type="text" name="Cname" value="" /><br><br> <input type="submit" value="Add Cookie" name="btnSubmit" /> </form> <% String CID, Cname; CID=request.getParameter("CID"); Cname=request.getParameter("Cname"); Cookie cookieCID = new Cookie ("cookieCID",CID); response.addCookie(cookieCID); Cookie cookieCname = new Cookie ("cookieCname",Cname); response.addCookie(cookieCname); out.print("CID cookie= " + CID + "added"); out.print("Cname cookie= " + Cname + "added"); %> Note: To view cookies with FireFox:Tools/Options/Privacy/Remove cookies
Reading Cookies Use request.getCookies() method. This method retrieve cookies and return them in an array. <% Cookie[] cookies = request.getCookies(); out.print(cookies[0].getName() + cookies[0].getValue() + "<br>"); out.print(cookies[1].getName() + cookies[1].getValue() + "<br>"); %>
Expire a cookie Add a expiration time: cookieCID setMaxAge(N); N is # of seconds N = 0, the cookie will be deleted right way N < 0 : the cookie will be deleted once the user exit the browser Cookie cookieCID = new Cookie ("cookieCID",CID); cookieCID.setMaxAge(-1);