ServerSide Scripting with Java Server Page JSP ISYS

Java Website • Java Tutorial: – http: //docs. oracle. com/javase/tutorial/ • JSP, Servlet tutorial:

Java Platforms • Java SE (Standard Edition) provides the core functionality of the Java

Hyper Text Transfer Protocol: Request & Response HTTP Request Web Server Browser HTTP Response

FORM • Form attribute: – Action: Specify the URL of a program on a

Query. String • A Query. String is a set of name=value pairs appended to

Data Sent with Request and Response • Request: – requested URL, cookies, query. String,

Java Server Pages, JSP • Java Server Pages (JSP) is a technology that lets

Methods of request Object • get. Parameter(String name): Returns the value of a request

Methods of response Object • add. Cookie(Cookie): Adds the specified cookie to the response.

JSP Out Object • print: The print method of out object writes the value

JSP scriptlet <% %> Example: <body> <h 1>Hello World!</h 1> <% out. print("Welcome!!!"); out.

In addition to the eight primitive data types listed above, the Java programming language

Form Example <body> <div>Compute the sum of two numbers</div> <form name="test. Form" method="post" action="compute.

Example of JSP scriptlet <% %> Compute the Sum of 2 Numbers: <body> <%

Example of get Method and get. Query. String() <% String value 1, value 2;

Writing HTML code as output <body> <% String value 1, value 2; double n

Embed JSP code in HTML Using JSP Expression: <%= %> <% String value 1,

Import Java Class Example: Display Current Date Time • Import java. util. Date –

Code Example <%@page import="java. util. Date"%> <%@page content. Type="text/html" page. Encoding="UTF-8"%> <html> <head> <meta

Compute Future Value: Process form with various controls

Form Code <form name="fv. Form" method="post" action="compute. FV. jsp"> Enter present value: <input type="text"

JSP Code Example <body> <% String my. PV, my. Rate, my. Year; my. PV=request.

Use Client-Side Validating and Sumbit Validated Form <script > function Validating(){ var Valid; Valid=true;

Check. Box Example A checkbox in a form: <input type="checkbox" name=“NPF" value="ON" /> Non-Profit

Depreciation Table Straight Line Depreciation Table <form name="dep. Form" method="post" action="create. Dep. Table. jsp">

<% String str. Value, str. Life; str. Value=request. get. Parameter("p. Value"); str. Life=request. get.

Number to Currency Format • Import class: – <%@page import="java. text. Number. Format"%> •

Using JSP Expression <body> <% String str. Value, str. Life; str. Value=request. get. Parameter("p.

Display Percentage Format: Import class: <%@page import="java. text. Number. Format"%> double rate = 0.

Date to Date Format • Import class: – <%@page import="java. text. Simple. Date. Format"%>

Java Array • Examples of declaring an array: – int[] an. Array = new

Creating a listbox of rates double[] rates= {0. 03, 0. 04, 0. 05, 0.

Compute Future Value: Process form with controls Created Using JSP Code: Note this page

JSP code to create the form <form name="fv. Form" method="post" action="compute. FV. jsp"> Enter

JSP Code to process the form <body> <% String my. PV, my. Rate, my.

Show selected rate and checked radio button checked box: “selected” radiobutton: “checked” <form name="fv.

Cookie • Cookie is a small data file added by a website to reside

Example: <form name="cust. Form" action="add. Cookie. jsp" method="POST"> Enter CID: <input type="text" name="CID" value=""

Reading Cookies Use request. get. Cookies() method. This method retrieve cookies and return them

Expire a cookie • Add a expiration time: – cookie. CID set. Max. Age(N);

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Server-Side Scripting with Java Server Page, JSP ISYS 350

Java Website • Java Tutorial: – http: //docs. oracle. com/javase/tutorial/ • JSP, Servlet tutorial: – http: //www. jsptut. com/ – http: //docs. oracle. com/javaee/5/tutorial/doc/bna gx. 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, multitiered, 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 Web Server Browser HTTP Response Web Application

Use JSP to Process a Form

FORM • Form attribute: – 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 Query. String. – Post: A preferred method for database processing. Form’s data is sent in the HTTP body. Post is the preferred method. Example: <form name="test. Form" method="post" action="compute. Sum. jsp“> • Button: – Type = “submit” <input type="submit" value="Compute. Sum. JSP" name="btn. Compute"/>

Query. String • A Query. String 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 Query. String: – Add a question mark (? ) immediately after a URL. – Followed by name=value pairs separated by ampersands (&). • Example: • <A Href=“http: //my. com/Target. htm? Cust. ID=C 1&Cname=Chao”>

Data Sent with Request and Response • Request: – requested URL, cookies, query. String, 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 dynamicallygenerated 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 • get. Parameter(String name): Returns the value of a request parameter as a String, or null if the parameter does not exist. • get. Query. String(): Gets any query string that is part of the HTTP request URI. • get. Cookies(): Gets the array of cookies found in this request. • get. Request. URI(): Gets the URI to the current JSP page. • etc.

Methods of response Object • add. Cookie(Cookie): Adds the specified cookie to the response. It can be called multiple times to set more than one cookie. • send. Redirect(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> <h 1>Hello World!</h 1> <% out. print("Welcome!!!"); out. print("To JSP Training"); %> </body> Question: How to start a new line? out. print(" 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="test. Form" method="post" action="compute. Sum. jsp"> Enter num 1: <input type="text" name="num 1" value="" /> Enter num 2: <input type="text" name="num 2" value="" /> <input type="submit" value="Compute. Sum. JSP" name="btn. Compute"/> </form> </body> Notre 1: The form has a method property nd action property. Note 2: The button now is type: submit, and there is no onclick event.

Example of JSP scriptlet <% %> Compute the Sum of 2 Numbers: <body> <% String value 1, value 2; double n 1, n 2, sum; value 1=request. get. Parameter("num 1"); value 2=request. get. Parameter("num 2"); n 1= Double. parse. Double(value 1); n 2= Double. parse. Double(value 2); sum=n 1+n 2; out. print("The sum is: " + sum); %> </body> Note 1: Double is an object that offers the parse. Double method, not “double” data type. Note 2: “out” is an implicit object that does not need to be declared. It is already predefined.

Example of get Method and get. Query. String() <% String value 1, value 2; double n 1, n 2, sum; String query. String=request. get. Query. String(); value 1=request. get. Parameter("num 1"); value 2=request. get. Parameter("num 2"); n 1= Double. parse. Double(value 1); n 2= Double. parse. Double(value 2); sum=n 1+n 2; out. print("The sum is: " + sum); out. print(" The query. String is: " + query. String); %>

Writing HTML code as output <body> <% String value 1, value 2; double n 1, n 2, sum; value 1=request. get. Parameter("num 1"); value 2=request. get. Parameter("num 2"); n 1= Double. parse. Double(value 1); n 2= Double. parse. Double(value 2); sum=n 1+n 2; out. print(" <p>Value 1: <input type=‘text' name='num 1' size='20' value='" + value 1 + "'></p>"); out. print(" <p>Value 2: <input type='text' name='num 2' size='20' value='" + value 2 + "'></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 value 1, value 2; double n 1, n 2, sum; value 1=request. get. Parameter("num 1"); value 2=request. get. Parameter("num 2"); n 1= Double. parse. Double(value 1); n 2= Double. parse. Double(value 2); sum=n 1+n 2; %> <form method="POST" name="test. Form" > <p>Value 1: <input type="text" name="num 1" size="20" value="<%=value 1%>"></p> <p>Value 2: <input type="text" name="num 2" size="20" value="<%=value 2%>"></p> <p> Sum is: <input type="text" name="num 2" size="20" value="<%=sum%>"></p> </form>

Import Java Class Example: Display Current Date Time • Import java. util. Date – <%@page import="java. util. Date"%> • Define a Date type variable: – Date current. Date = new Date(); • Display in textbox using JSP expression: <p>The time is: <input type="text" name="num 2" size="20" value="<%=current. Date%>"></p>

Code Example <%@page import="java. util. Date"%> <%@page content. Type="text/html" page. Encoding="UTF-8"%> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF 8"> <title>JSP Page</title> </head> <body> <% Date current. Date = new Date(); %> <p>The time is: <input type="text" name="num 2" size="20" value="<%=current. Date%>"></p> </body> </html>

Compute Future Value: Process form with various controls

Form Code <form name="fv. Form" method="post" action="compute. FV. jsp"> Enter present value: <input type="text" name="PV" value="" /> 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> Select year: <input type="radio" name="Year" value="10" />10 -year <input type="radio" name="Year" value="15" />15 -year <input type="radio" name="Year" value="30" />30 -year <input type="submit" value="Compute. FVJSP" name="btn. Compute" /> </form>

JSP Code Example <body> <% String my. PV, my. Rate, my. Year; my. PV=request. get. Parameter("PV"); my. Rate=request. get. Parameter("Rate"); my. Year=request. get. Parameter("Year"); double FV, PV, Rate, Year; PV=Double. parse. Double(my. PV); Rate=Double. parse. Double(my. Rate); Year=Double. parse. Double(my. Year); FV=PV*Math. pow(1+Rate, Year); out. print("Future. Value is: "+ FV); %>

Use Client-Side Validating and Sumbit Validated Form <script > function Validating(){ var Valid; Valid=true; if (document. fv. Form. PV. value=="") {Valid=false; } if (Valid==false){alert("Cannot contain blank"); } else {document. fv. Form. submit(); } } </script> Note: Must use a standard button, not submit button: <input type="button" value="Compute. FVJSP" name="btn. Compute" onclick="Validating()"/>

Check. Box Example A checkbox in a form: <input type="checkbox" name=“NPF" value="ON" /> Non-Profit In JSP program: my. Chk=request. get. Parameter(“NPF"); if (my. Chk=="ON") out. print("Checkbox is on!"); else out. print(“Checkbox is off!");

Depreciation Table Straight Line Depreciation Table <form name="dep. Form" method="post" action="create. Dep. Table. jsp"> Enter Property Value: <input type="text" name="p. Value" value="" /> Enter Property Life: <input type="text" name="p. Life" value="" /> <input type="submit" value="Show. Table JSP" name="btn. Show. Table" /> </form>

Output

<% String str. Value, str. Life; str. Value=request. get. Parameter("p. Value"); str. Life=request. get. Parameter("p. Life"); double value, life, depreciation, total. Depreciation=0; value=Double. parse. Double(str. Value); life=Double. parse. Double(str. Life); depreciation=value/life; Number. Format nf = Number. Format. get. Currency. Instance(); out. print("Stright Line Depreciation Table" + " "); out. print("Property Value: <input type='text' name='p. Value' value='" + nf. format(value) + "' /> "); out. print("Property Life: <input type='text' name='p. Life' value='" + life + "' /> "); total. Depreciation=0; out. print( "<table border='1' width='400' cellspacing=1>"); out. print("<thead> <tr> <th>Year</th> <th>Value at Begin. Yr</th>"); out. print("<th>Dep During Yr</th> <th>Total to End. Of. Yr</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>"); total. Depreciation+=depreciation; out. print(" <td>" + nf. format(total. Depreciation) + "</td>"); value -= depreciation; } %>

Number to Currency Format • Import class: – <%@page import="java. text. Number. Format"%> • Define a format: – Number. Format nf = Number. Format. get. Currency. Instance(); • Convert: – Example: Display payment with currency format: nf. format(payment)

Using JSP Expression <body> <% String str. Value, str. Life; str. Value=request. get. Parameter("p. Value"); str. Life=request. get. Parameter("p. Life"); double value, life, depreciation, total. Depreciation=0; value=Double. parse. Double(str. Value); life=Double. parse. Double(str. Life); Number. Format nf = Number. Format. get. Currency. Instance(); depreciation=value/life; total. Depreciation=depreciation; %> <p>Straight Line Depreciation Table</p> <p>Property Value: <input type='text' name='p. Value' value='<%=nf. format(value)%>' /></p> <p>Property Life: <input type='text' name='p. Life' value='<%=life%>'/></p> <table border='1' width='400' cellspacing=1> <thead> <tr> <th>Year</th> <th>Value at Begin. Yr</th> <th>Dep During Yr</th> <th>Total to End. Of. Yr</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(total. Depreciation)%></td> </tr> <% value -= depreciation; total. Depreciation+=depreciation; } %> </table> </body>

Display Percentage Format: Import class: <%@page import="java. text. Number. Format"%> double rate = 0. 05267; Number. Format p. Format = Number. Format. get. Percent. Instance(); p. Format. set. Minimum. Fraction. Digits(2); out. println("Percent format: " + p. Format. format(rate));

Date to Date Format • Import class: – <%@page import="java. text. Simple. Date. Format"%> – Define a format: • Simple. Date. Format formatter = new Simple. Date. Format("MM/dd/yy"); – Convert: • Example: Display a date with date format: String display. Date = formatter. format(current. Date);

Java Array • Examples of declaring an array: – int[] an. Array = new int[10]; • 10 elements index from 0 to 9 – double[] an. Array. Of. Doubles = new double[10]; – String[] an. Array. Of. Strings = new String[10]; – int[] an. Array = { 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> ");

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="fv. Form" method="post" action="compute. FV. jsp"> Enter present value: <input type="text" name="PV" value="" /> <% 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> "); double[] year. Values= {10, 15, 30}; String[] year. Labels={"10 -year", "15 -year", "30 -year"}; out. print( "Select year: "); for (int i = 0; i <= year. Values. length-1; i++) { out. print("<input type='radio' name='Year' value='" + year. Values[i] + "'/>" + year. Labels[i] + " "); } %> <input type="submit" value="Compute. FVJSP" name="btn. Compute" />

JSP Code to process the form <body> <% String my. PV, my. Rate, my. Year; my. PV=request. get. Parameter("PV"); my. Rate=request. get. Parameter("Rate"); my. Year=request. get. Parameter("Year"); double FV, PV, Rate, Year; PV=Double. parse. Double(my. PV); Rate=Double. parse. Double(my. Rate); Year=Double. parse. Double(my. Year); FV=PV*Math. pow(1+Rate, Year); out. print("Future. Value is: "+ FV); %>

Show selected rate and checked radio button checked box: “selected” radiobutton: “checked” <form name="fv. Form"> Enter present value: <input type="text" name="PV" value="<%=PV%>" /> <% 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> "); double[] year. Values= {10, 15, 30}; String[] year. Labels={"10 -year", "15 -year", "30 -year"}; out. print( "Select year: "); for (int i = 0; i <= year. Values. length-1; i++) { if(year. Values[i]==Year) out. print("<input type='radio' name='Year' value='" + year. Values[i] + "' checked/>" + year. Labels[i] + " "); else out. print("<input type='radio' name='Year' value='" + year. Values[i] + "'/>" + year. Labels[i] + " "); }

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 cookie. CID = new Cookie ("cookie. CID", CID); • Write a cookie: – response. add. Cookie(cookie. CID);

Example: <form name="cust. Form" action="add. Cookie. jsp" method="POST"> Enter CID: <input type="text" name="CID" value="" /> Enter Cname: <input type="text" name="Cname" value="" /> <input type="submit" value="Add Cookie" name="btn. Submit" /> </form> <% String CID, Cname; CID=request. get. Parameter("CID"); Cname=request. get. Parameter("Cname"); Cookie cookie. CID = new Cookie ("cookie. CID", CID); response. add. Cookie(cookie. CID); Cookie cookie. Cname = new Cookie ("cookie. Cname", Cname); response. add. Cookie(cookie. Cname); out. print("CID cookie= " + CID + "added"); out. print("Cname cookie= " + Cname + "added"); %> Note: To view cookies with Fire. Fox: Tools/Options/Privacy/Remove cookies

Reading Cookies Use request. get. Cookies() method. This method retrieve cookies and return them in an array. <% Cookie[] cookies = request. get. Cookies(); out. print(cookies[0]. get. Name() + cookies[0]. get. Value() + " "); out. print(cookies[1]. get. Name() + cookies[1]. get. Value() + " "); %>

Expire a cookie • Add a expiration time: – cookie. CID set. Max. Age(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 cookie. CID = new Cookie ("cookie. CID", CID); cookie. CID. set. Max. Age(-1);