School of Computer Science 15-415 Fall 2009 Recitation Homework 9 Building A Web Application Phase-II Leman Akoglu 11/11/2009

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Transcript School of Computer Science 15-415 Fall 2009 Recitation Homework 9 Building A Web Application Phase-II Leman Akoglu 11/11/2009 

School of Computer Science
15-415 Fall 2009
Recitation
Homework 9
Building A Web Application
Phase-II
Leman Akoglu
11/11/2009
Phase-I
Phase-II
description
conc. mod.
impl.+test.
req. anal.
top level I.F.D.
schema.
code.
tests
user’s man.
sys. anal.
task + doc forms.
2
task emul.
pseudo-code
Phase II
You will develop
 JSP pages that handle user interactions
 Processing logic written in Java class
 Manipulating data in database, connect from JSP to
database using JDBC
3
Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
4
Recommended Schema for HW9
 users(login, password, name, email)
 photos(URL, owner)
 tags(URL, tagger, taggee, timestamp)
 likes(user1, user2)
5
Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
6
Typical Web Application Architecture
Web Server
Client
Apache,
Tomcat,
Windows IIS
Web app
Users
Backend Server
Java Virtual
Machine
(JSP, ASP, PHP)
Web app
backend
component
Database
Server
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Homework 9:
CMUBook architecture
Web Server
newcastle.db.cs.cmu.edu
Client
PostgreSQL
Browser
Tomcat 5.5
Database Server
http
newcastle.db.cs.cmu.edu
User
CMUBook
JSP, Java
8
JDBC
hw9
database
Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
9
CMUBook architecture
Registration example –register.jsp
1 http://newcastle
.db.cs.cmu.edu:
8080/lakoglu415
Client
/register.jsp
Browser
newcastle.db.cs.cmu.edu
PostgreSQL
Tomcat 5.5
User
2
html page with
input FORM
CMUBook
3
Submit FORM
with login, name,
password and
email
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Web Server
JSP, Java
6
Html page with successful info
register.jsp
Database
Server
4
JDBC exec. query newcastle.db.cs.cm
u.edu
java.sqlStatement.
executeUpdate()
hw9
database
JDBC insert
succeeds
5
Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
11
JSP Basics
 Three primitives
 – expressions
 – directives
 – declarations
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JSP Basics – expressions
 JSP simply puts Java inside HTML pages.
 JSP is being turned into a Java file, compiled and loaded
<HTML> <BODY>
Hello! The time is now <%= new java.util.Date() %>
</BODY> </HTML>
 <%= and %> enclose Java expressions, which are evaluated
at run time
 Scriptlets: blocks of Java code (<% and %>)
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JSP Basics – directives
 JSP "directives" starts with <%@ characters.
 "page directive":
<%@ page import="java.util.*,java.text.*" %>
 “include directive”:
<%@ include file="hello.jsp" %>
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JSP Basics – declarations
 The JSP code turns into a class definition. All the scriptlets are
placed in a single method of this class.
 Can add variable and method declarations to this class. These
variables and methods can later be “called” from your scriptlets
and expressions.
 <%! and %> sequences enclose your declarations
<%@ page import="java.util.*" %>
<HTML> <BODY>
<%!
Date theDate = new Date();
Date getDate() {
System.out.println( "In getDate() method" );
return theDate;
}
%>
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Hello! The time is now <%= getDate() %>
</BODY> </HTML>
JSP Basics - communication w/ server
 A "request" in server-side processing refers to the
transaction between a browser and the server.
 request.getRemoteHost();
 request.getParameter(“login”);
 A "response" is used to affect the response being sent to the
browser.
 response.addCookie(cookie);
 response.sendRedirect(anotherUrl);
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Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
17
How to connect to the database
<%
…
Connection conn = null;
Statement stmt = null;
ResultSet r = null;
Class.forName("org.postgresql.Driver");
conn = DriverManager.getConnection
("jdbc:postgresql://localhost:40123/hw9?
user=www&password=lakoglu415");
stmt = conn.createStatement();
r = stmt.executeQuery(your-SQL-query);
if (r.next()) {
session.setAttribute("login", r.getString(1));
…
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%>
register.jsp
Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
19
JSP Basics – sessions – method#1
 Http protocol is a stateless protocol, that means that it can't
persist the data.
 A session is an object associated with a visitor.
 Data can be put in the session and retrieved from it, much
like a Hashtable.
 session.setAttribute( "theName", name );
 session.getAttribute( "theName" )
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(Optional)
JSP Basics – cookies – method#2
 Cookies are commonly used for session management.
 short pieces of data sent by web servers to the client
browser
 saved to clients hard disk in the form of a small text file
 helps the web servers to identify web users, by this way
server tracks the user.
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Cookie example
String username=request.getParameter("username");
Cookie cookie = new Cookie ("username",username);
cookie.setMaxAge(365 * 24 * 60 * 60);
response.addCookie(cookie);
<%
String cookieName = "username";
Cookie cookies [] = request.getCookies ();
Cookie myCookie = null;
if (cookies != null){
for (int i = 0; i < cookies.length; i++) {
if (cookies [i].getName().equals (cookieName)){
myCookie = cookies[i];
break;
}
}
}
%>
<p>Welcome: <%=myCookie.getValue()%>.
<%
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Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
23
Exception Handling
try {
….
}
catch (Exception ex) {
ex.printStackTrace();
out.println("Login failed!");
out.println("<a href=login.jsp>Go back to login!</a>");
}
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Outline
 Recommended Schema for HW9
 A Typical Web Application Architecture
 CMUBook architecture
 JSP mini demo  register.jsp




JSP Basics
How to connect to the database
Session and cookie management  login.jsp
Exception handling
 Demo
25
Lets put things together…
 register.jsp
<html>
<%@ page import="java.sql.*"%>
<%
String fullname = request.getParameter("fullname");
String email = request.getParameter("email");
String login = request.getParameter("login");
String passwd = request.getParameter("passwd");
String submit = request.getParameter("submit");
if (submit==null) {
%>
<body>
<h1>
CMUBook Registration
</h1>
<form method="post" action="register.jsp">
Login Name: <input name="login" type="text" /> <br />
Full Name: <input name="fullname" type="text" /> <br />
Password: <input name="passwd" type="password" /> <br />
Email: <input name="email" type="text" /> <br />
<input name="submit" type="submit" value="Submit" />
</form>
</body>
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<%
} else {
%>
<body>
<%
Connection conn = null;
Statement stmt = null;
try {
Class.forName("org.postgresql.Driver");
conn =
DriverManager.getConnection("jdbc:postgresql://localhost:40123/hw9?user=www&password=lakoglu415");
stmt = conn.createStatement();
int r = stmt.executeUpdate("INSERT INTO
users(login, fullname, passwd, email) VALUES ('" + login + "','" + fullname + "','" + passwd + "','" + email + "')");
if (r==1) {
out.println("Registration successful!");
out.println("<a href=login.jsp>Log In</a>");
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} else {
out.println("Registration failed!");
}
} catch (Exception ex) {
ex.printStackTrace();
} finally {
//this is important. You should free up resources. Always. In a finally block.
stmt.close();
conn.close();
}
%>
</body>
<%
}
%>
</html>
Lets put things together…
 login.jsp
<html>
<%@ page import="java.sql.*"%>
<%
String login = request.getParameter("login");
String passwd = request.getParameter("passwd");
String submit = request.getParameter("submit");
if (submit==null) {
%>
<body>
<h1>
CMUBook Login Page
</h1>
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<form method="post" action="login.jsp">
Login ID: <input name="login" type="text" /> <br />
Password: <input name="passwd" type="password" /> <br />
<input name="submit" type="submit" value="Submit" />
</form>
</body>
<%
} else {
%>
<body>
<%
Connection conn = null;
Statement stmt = null;
ResultSet r = null;
try {
Class.forName("org.postgresql.Driver");
conn = DriverManager.getConnection("jdbc:postgresql://localhost:40123/hw9?user=www&password=lakoglu415");
stmt = conn.createStatement();
r = stmt.executeQuery("SELECT * FROM users WHERE login='" + login + "' and passwd='" + passwd + "'");
if (r.next()) {
session.setAttribute("login", r.getString(1));
response.sendRedirect("user.jsp");
} else {
out.println("Login failed!!");
out.println("<a href=login.jsp>Log In</a>");
out.println("<a href=register.jsp>Register</a>");
}
} catch (Exception ex) {
out.println("Login failed!");
} finally {
//this is important. You should free up resources. Always. In a finally block.
stmt.close();
conn.close();
}
%>
</body>
<%
}
%>
</html>
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Lets put things together…
 user.jsp
<html>
<%@ page import="java.sql.*"%>
<body>
<br>
<b>Welcome <%= session.getAttribute( "login" )%></b>
<br />
</body>
</html>
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