Presentation

Java Servlets
Java Server Pages
(JSP)

Overview of History
CGI
(in C)
Template
(ASP, PHP)
Servlet
CGI
(java, C++)
JSP
Speed, Security
complexity

HelloWorld
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HelloWorld extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<body>");
out.println("<head>");
out.println("<title>Hello CS764!</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Hello CS764!</h1>");
out.println("</body>");
out.println("</html>");
out.close();
}
}

<html><head></head>
<body>
<a href="../servlet/HelloWorld">
<h1>Execute HelloWorld Servlet</h1>
</a>
</body>
</html>
<html>
<head>
<title>Hello CS764!</title></head>
<body>
<h1>Hello CS764!</h1>
</body>
</html>

Client - Server - DB
Client
(browser)
Web server
(Apache, JWS)
Database
server (DB2)
Through
internet
Return html file
(Response)
Trigger Servlet, JSP
(Request)
JDBC,
intranet
Request
data
Return
data

Life Cycle of Servlet
init(ServletConfig);
service(ServletRequest,
ServletResponse);
destroy();
servlet
GenericServlet HttpServlet
doGet(HttpServletRequest,
HttpServletResponse);
doPost(HttpServletRequest,
HttpServletResponse);
…….

Interaction with Client
• HttpServletRequest
– String getParameter(String)
– Enumeration getParameters(String[])
• HttpServletResponse
– Writer getWriter()
– ServletOutputStream getOutputStream()
• Handling GET and POST Requests

Assignment 2:
Get Stock Price
<html><head></head>
<body>
<form action="../servlet/Ass2Servlet"
method=POST>
<h2>Stock Symbol name:
<input type=text name="stockSymbol"></h2><br>
<input type="submit" value = "get price">
</form>
</body></html>
Client Side
Ass2.html

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Ass2Servlet extends HttpServlet {
public void doPost(HttpServletRequest request,
HttpServletResponse res)
throws IOException, ServletException
{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
String stockSymb = request.getParameter("stockSymbol");
StockGrabber sg = new StockGrabber();
sg.setStockSymbol(stockSymb); // Set the stock symbol as “input”
String stockPrice = sg.getPrice();// Get the price of stock
System.out.println("After StockGrabber.getPrice --"+stockPrice);// Debug
out.println("<html><head></head><body><br><br>");
out.println(stockSymb + " -- " + stockPrice);
out.println("<hr>");
out.println("<form action="../servlet/Ass2Servlet" method=POST>");
out.println("<h3>Stock Symbol name: <input type=text name="stockSymbol"></h3>");
out.println("<input type=submit value="get price">");
out.println("</form>");
out.println("</body></html>");
}
}
Ass2Servlet

Java Server Pages (JSP)
Client’s
Computer
Server
1.Browser requests HTML
7. Server sends HTML
back to browser
servlet
servlet
class 5.The servlet
runs and
generates
HTML
Java Engine
6. Java Engine sends HTML to server
2. Server sends requests to Java Engine
3. If needed, the Java Engine
reads the .jsp file
4. The JSP is turned into a
servlet, compiled, and loaded
Bean

A First JSP
<html>
<head></head>
<body>
<p>Enter two numbers and click the
‘calculate’ button.</p>
<form action=“calculator.jsp” method=“get”>
<input type=text name=value1><br>
<input type=text name=value2 ><br>
<input type=submit name=calculate value=calculate>
</form>
</body>
</html>
Calculator.html

<html>
<head><title>A simple calculator: results</title></head>
<body>
<%-- A simpler example 1+1=2 --%>
1+1 = <%= 1+1 %>
<%-- A simple calculator --%>
<h2>The sum of your two numbers is:</h2>
<%= Integer.parseInt(request.getParameter("value1")) +
Integer.parseInt(request.getParameter("value2")) %>
</body>
</html>
Calculator.jsp

JSP Tags
• Comments <%-- …...text…... --%>
• Declaration <%! int i; %>
<%! int numOfStudents(arg1,..) {} %>
• Expression <%= 1+1 %>
• Scriptlets <% … java code … %>
• include file <%@ include file=“*.jsp” %>
• …...

Using Java Bean
1. <jsp:useBean id=“bean1” class=“Bean1”/>
2. <jsp:useBean id=“bean1” class=“Bean1” name=“serBean” type=“SerBean1”/>
Declaration
Getting property
1. <jsp:getProperty name=“bean1” property=“color”/>
2. <%=bean1.getColor() %>
Setting property
1. <jsp:setProperty name=“bean1” property=“color” value=“red”/>
2. <jsp:setProperty name=“bean1” property=“color”/>
3. <jsp:setProperty name=“bean1” property=“color” param=“bgColor”/>
4. <jsp:setProperty name=“bean1” property=“*”/>

Assg2
example
<html>
<head></head>
<body>
<center>
<table border = 0>
<form action=ass2.jsp method = POST>
<tr><td><font color=blue>choose a stock market:</font></td>
<td><select name="stockMarket">
<option value="Waterhouse">Waterhouse</option>
<option value="Yahoo">Yahoo</option>
<option value="ChicagoStockex">Chicago Stockex</option>
<option value="Reuters">Reuters</option>
</select></td>
</tr>
<tr><td><font color = blue>input a stock symbol:</font></td>
<td><input type="edit" name="stockSymbol" size=15></td>
</tr>
<tr><td></td><td><input type="submit" value = "get price"></td></tr>
</table>
</form></center>
</body></html>
Client side
Ass2.html

Server side
ass2.jsp
<html><head>
<jsp:useBean id="ass2" scope="session" class="ass2.StockGrabber" />
<jsp:setProperty name="ass2" property="*" />
</head>
<body><h2><%
ass2.processInput();
ass2.getPrice();
%>
<center><table border=5>
<tr><td># of data</td> <td>Stock Market</td> <td>Stock Symbol</td> <td>Stock Price </td>
</tr><%
String[] stockMarkets = ass2.getStockMarkets();
String[] symbols = ass2.getSymbols();
String[] prices = ass2.getPrices();
for(int i=0; i<prices.length; i++){
%>
<tr><td> <%= i+1 %> </td>
<td> <%= stockMarkets[i] %> </td>
<td> <%= symbols[i] %> </td>
<td><font color=red><%= prices[i] %></font></td>
</tr><%
}
%>
</table>
</center>
</h2>
<hr><%@include file="ass2.html" %></html>
<jsp:setProperty name=“ass2” property=“stockSymbol”/>
<jsp:setProperty name=“ass2” property=“stockMarket”/>

Without using JDBC
Public class StockGrabber {
...
public void processInput(){
if(stockMarket.compareTo("Waterhouse")==0){
setPrePriceString("");
setPostPriceString("</FONT>");
setUrlPrefix("http://research.tdwaterhouse.com/
waterhouse/quote.asp?ticker=");
}
else if(stockMarket.compareTo("Yahoo")==0){
setPrePriceString("<td nowrap><b>");
setPostPriceString("</b></td>");
setUrlPrefix("http://finance.yahoo.com/q?s=");
}
...
else if(...){}
...
else{...}
}
...
}

Using JDBC --> Database
import java.sql.*;
Public class StockGrabber {
...
public void processInput(){
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
String sourceURL="jdbc:odbc:stockInfo";
Connection databaseConnection=DriverManager.getConnection(sourceURL);
Statement statement=databaseConnection.createStatement();
ResultSet info =statement.executeQuery(
"select tPrePriceStr, tPostPriceStr, tUrlPrefix
from stockMarketData
where tStockMarket = stockMarket”);
while(inf.next())
{
prePriceString = info.getString(”tPrePriceStr");
postPriceString = info.getString(“tPostPriceStr”);
urlPrefix = info.getString(“tUrlPrefix”);
}
}
catch(SQLException e){ ... }
...
}
}

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