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- 9. Session Handling using cookies
- index.html
- <form method="post" action=" validate ">
- Name:<input type="text" name="user" /><br/>
- Password:<input type="text" name="pass" ><br/>
- <input type="submit" value="submit">
- </form>
- web.xml
- <webapp...>
- <servlet>
- <servletname>
- validate </servletname>
- <servletclass>
- MyServlet </servletclass>
- </servlet>
- <servletmapping>
- <servletname>
- validate </servletname>
- <urlpattern>/
- validate</urlpattern>
- </servletmapping>
- <servlet>
- <servletname>
- First </servletname>
- <servletclass>
- First </servletclass>
- </servlet>
- <servletmapping>
- <servletname>
- First </servletname>
- <urlpattern>/
- First</urlpattern>
- </servletmapping>
- <welcomefilelist>
- <welcomefile>
- index.html </welcomefile>
- </welcomefilelist>
- </webapp>
- MyServlet.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class MyServlet extends HttpServlet {
- protected void doPost (HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- String name = request.getParameter(" user ");
- String pass = request.getParameter(" pass ");
- if(pass. equals ("1234"))
- {
- Cookie ck = new Cookie(" username ", name );
- response. addCookie ( ck );
- response.sendRedirect(" First ");
- }
- }
- }
- First.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class First extends HttpServlet {
- protected void doGet (HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- PrintWriter out = response.getWriter();
- Cookie[] cks = request.getCookies();
- out.println("Welcome "+ cks[0].getValue() );
- }
- }
- 10.
- Session Hndling using URL Rewriting
- index.html
- <form method="post" action=" validate ">
- Name:<input type="text" name="user" /><br/>
- Password:<input type="text" name="pass" ><br/>
- <input type="submit" value="submit">
- </form>
- web.xml
- <webapp...>
- <servlet>
- <servletname>
- validate </servletname>
- <servletclass>
- MyServlet </servletclass>
- </servlet>
- <servletmapping>
- <servletname>
- validate </servletname>
- <urlpattern>/
- validate</urlpattern>
- </servletmapping>
- <servlet>
- <servletname>
- First </servletname>
- <servletclass>
- First </servletclass>
- </servlet>
- <servletmapping>
- <servletname>
- First </servletname>
- <urlpattern>/
- First</urlpattern>
- </servletmapping>
- <welcomefilelist>
- <welcomefile>
- index.html </welcomefile>
- </welcomefilelist>
- </webapp>
- MyServlet.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class MyServlet extends HttpServlet {
- protected void doPost (HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- String name = request.getParameter(" user ");
- String pass = request.getParameter(" pass ");
- if(pass. equals ("1234"))
- {
- response.sendRedirect( "First?user_name="+ name +"" );
- }
- }
- }
- First.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class First extends HttpServlet {
- protected void doGet (HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- PrintWriter out = response.getWriter();
- String user = request.getParameter(" user_name ");
- out.println("Welcome "+user);
- }
- }
- 11. Session management using hidden form fields :
- index.html
- <form method="post" action=" validate ">
- Name:<input type="text" name="user" /><br/>
- Password:<input type="text" name="pass" ><br/>
- <input type="submit" value="submit">
- </form>
- web.xml
- <webapp...>
- <servlet>
- <servletname>
- First </servletname>
- <servletclass>
- First </servletclass>
- </servlet>
- <servletmapping>
- <servletname>
- First </servletname>
- <urlpattern>/
- First</urlpattern>
- </servletmapping>
- <servlet>
- <servletname>
- Second </servletname>
- <servletclass>
- Second </servletclass>
- </servlet>
- <servletmapping>
- <servletname>
- Second </servletname>
- <urlpattern>/
- Second</urlpattern>
- </servletmapping>
- <welcomefilelist>
- <welcomefile>
- index.html </welcomefile>
- </welcomefilelist>
- </webapp>
- First.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class First extends HttpServlet {
- protected void doPost (HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- PrintWriter out = response.getWriter();
- //getting value submitted in form from HTML file
- String user = request.getParameter("user");
- //creating a new hidden form field
- out.println("<form action='Second'>");
- out.println("<input type='hidden' name='user' value='"+ user +"'>");
- out.println("<input type='submit' value='submit' >");
- out.println("</form>");
- }
- }
- Second.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class Second extends HttpServlet {
- protected void doGet (HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- PrintWriter out = response.getWriter();
- //getting parameter from the hidden field
- String user = request.getParameter(" user ");
- out.println("Welcome "+ user );
- }
- }
- HTTP Session
- 12. http://www.studytonight.com/servlet/httpsession.php
- index.html
- <form method="post" action=" Validate ">
- User: <input type="text" name="user" /><br/>
- Password: <input type="text" name="pass" ><br/>
- <input type="submit" value="submit">
- </form>
- web.xml
- <webapp..>
- <servlet>
- <servletname>
- Validate </servletname>
- <servletclass>
- Validate </servletclass>
- </servlet>
- <servlet>
- <servletname>
- Welcome </servletname>
- <servletclass>
- Welcome </servletclass>
- </servlet>
- <servletmapping>
- <servletname>
- Validate</servletname>
- <urlpattern>/
- Validate</urlpattern>
- </servletmapping>
- <servletmapping>
- <servletname>
- Welcome</servletname>
- <urlpattern>/
- Welcome</urlpattern>
- </servletmapping>
- <welcomefilelist>
- <welcomefile>
- index.html </welcomefile>
- </welcomefilelist>
- </webapp>
- Validate.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class Validate extends HttpServlet {
- protected void doPost (HttpServletRequest request, HttpServletResponse
- response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- String name = request.getParameter("user");
- String pass = request.getParameter("pass");
- if(pass. equals ("1234"))
- {
- //creating a session
- HttpSession session = request.getSession();
- session. setAttribute (" user ", name );
- response. sendRedirect ("Welcome");
- }
- }
- }
- Welcome.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class Welcome extends HttpServlet {
- protected void doGet (HttpServletRequest request, HttpServletResponse
- response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=UTF8");
- PrintWriter out = response.getWriter();
- HttpSession session = request.getSession();
- String user = (String)session.getAttribute(" user ");
- out.println("Hello "+ user );
- }
- }
- 13. Servelet Collaboration REquest
- dispatch
- http://www.javatpoint.com/requestdispatcherinservlet
- index.html
- <form action= "servlet1" method= "post" >
- Name:<input type= "text" name= "userName" /><br/>
- Password:<input type= "password" name= "userPass" /><br/>
- <input type= "submit" value= "login" />
- </form>
- Login.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class Login extends HttpServlet {
- public void doPost(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType( "text/html" );
- PrintWriter out = response.getWriter();
- String n=request.getParameter( "userName" );
- String p=request.getParameter( "userPass" );
- if (p.equals( "servlet" ){
- RequestDispatcher rd=request.getRequestDispatcher( "servlet2" );
- rd.forward(request, response);
- }
- else {
- out.print( "Sorry UserName or Password Error!" );
- RequestDispatcher rd=request.getRequestDispatcher( "/index.html" );
- rd.include(request, response);
- }
- }
- }
- WelcomeServlet.java
- import java.io.*;
- import javax.servlet.*;
- import javax.servlet.http.*;
- public class WelcomeServlet extends HttpServlet {
- public void doPost(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType( "text/html" );
- PrintWriter out = response.getWriter();
- String n=request.getParameter( "userName" );
- out.print( "Welcome " +n);
- }
- }
- web.xml<webapp>
- <servlet>
- <servletname>
- Login</servletname>
- <servletclass
- >Login</servletclass
- >
- </servlet>
- <servlet>
- <servletname>
- WelcomeServlet</servletname>
- <servletclass
- >WelcomeServlet</servletclass
- >
- </servlet>
- <servletmapping>
- <servletname>
- Login</servletname>
- <urlpattern>/
- servlet1</urlpattern>
- </servletmapping>
- <servletmapping>
- <servletname>
- WelcomeServlet</servletname>
- <urlpattern>/
- servlet2</urlpattern>
- </servletmapping>
- <welcomefilelist>
- <welcomefile>
- index.html</welcomefile>
- </welcomefilelist>
- </webapp>
- 14. Servlet Collab using Servlet context
- 15. Filterss
- http://www.javatpoint.com/servletfilter
- 16. Jdbc for insert and extract details from a table
- //STEP 1. Import required packages
- import java . sql .*;
- public class JDBCExample {
- // JDBC driver name and database URL
- static final String JDBC_DRIVER = "com.mysql.jdbc.Driver" ;
- static final String DB_URL = "jdbc:mysql://localhost/STUDENTS" ;
- // Database credentials
- static final String USER = "username" ;
- static final String PASS = "password" ;
- public static void main ( String [] args ) {
- Connection conn = null ;
- Statement stmt = null ;
- try {
- //STEP 2: Register JDBC driver
- Class . forName ( "com.mysql.jdbc.Driver" );
- //STEP 3: Open a connection
- System . out . println ( "Connecting to a selected database..." );
- conn = DriverManager . getConnection ( DB_URL , USER , PASS );
- System . out . println ( "Connected database successfully..." );
- //STEP 4: Execute a query
- System . out . println ( "Creating statement..." );
- stmt = conn . createStatement ();
- String sql = "SELECT id, first, last, age FROM Registration" ;
- ResultSet rs = stmt . executeQuery ( sql );
- //STEP 5: Extract data from result set
- while ( rs . next ()){
- //Retrieve by column name
- int id = rs . getInt ( "id" );
- int age = rs . getInt ( "age" );
- String first = rs . getString ( "first" );
- String last = rs . getString ( "last" );
- //Display values
- System . out . print ( "ID: " + id );
- System . out . print ( ", Age: " + age );
- System . out . print ( ", First: " + first );
- System . out . println ( ", Last: " + last );
- }
- rs . close ();
- } catch ( SQLException se ){
- //Handle errors for JDBC
- se . printStackTrace ();
- } catch ( Exception e ){
- //Handle errors for Class.forName
- e . printStackTrace ();
- } finally {
- //finally block used to close resources
- try {
- if ( stmt != null )
- conn . close ();
- } catch ( SQLException se ){
- } // do nothing
- try {
- if ( conn != null )
- conn . close ();
- } catch ( SQLException se ){
- se . printStackTrace ();
- } //end finally try
- } //end try
- System . out . println ( "Goodbye!" );
- } //end main
- } //end JDBCExample
- 17. Servlet databse insert:
- http://www.tutorialspoint.com/servlets/pdf/servletsdatabaseaccess.
- pdf
- // Loading required libraries
- import java . io .*;
- import java . util .*;
- import javax . servlet .*;
- import javax . servlet . http .*;
- import java . sql .*;
- public class DatabaseAccess extends HttpServlet {
- public void doGet ( HttpServletRequest request ,
- HttpServletResponse response )
- throws ServletException , IOException
- {
- // JDBC driver name and database URL
- static final String JDBC_DRIVER = "com.mysql.jdbc.Driver" ;
- static final String DB_URL = "jdbc:mysql://localhost/TEST" ;
- // Database credentials
- static final String USER = "root" ;
- static final String PASS = "password" ;
- // Set response content type
- response . setContentType ( "text/html" );
- PrintWriter out = response . getWriter ();
- String title = "Database Result" ;
- String docType =
- "<!doctype html public \"//
- w3c//dtd html 4.0 " +
- "transitional//en\">\n" ;
- out . println ( docType +
- "<html>\n" +
- "<head><title>" + title + "</title></head>\n" +
- "<body bgcolor=\"#f0f0f0\">\n" +
- "<h1 align=\"center\">" + title + "</h1>\n" );
- try {
- // Register JDBC driver
- Class . forName ( "com.mysql.jdbc.Driver" );
- // Open a connection
- Connection conn = DriverManager . getConnection ( DB_URL , USER , PASS );
- // Execute SQL query
- Statement stmt = conn . createStatement ();
- String sql ;
- sql = "SELECT id, first, last, age FROM Employees" ;
- ResultSet rs = stmt . executeQuery ( sql );
- // Extract data from result set
- while ( rs . next ()){
- //Retrieve by column name
- int id = rs . getInt ( "id" );
- int age = rs . getInt ( "age" );
- String first = rs . getString ( "first" );
- String last = rs . getString ( "last" );
- //Display values
- out . println ( "ID: " + id + "<br>" );
- out . println ( ", Age: " + age + "<br>" );
- out . println ( ", First: " + first + "<br>" );
- out . println ( ", Last: " + last + "<br>" );
- }
- out . println ( "</body></html>" );
- // Cleanup
- environment
- rs . close ();
- stmt . close ();
- conn . close ();
- } catch ( SQLException se ){
- //Handle errors for JDBC
- se . printStackTrace ();
- } catch ( Exception e ){
- //Handle errors for Class.forName
- e . printStackTrace ();
- } finally {
- //finally block used to close resources
- try {
- if ( stmt != null )
- stmt . close ();
- } catch ( SQLException se2 ){
- } // nothing we can do
- try {
- if ( conn != null )
- conn . close ();
- } catch ( SQLException se ){
- se . printStackTrace ();
- } //end finally try
- } //end try
- }
- }
- Now let us compile above servlet and create following entries in web.xml
- ....
- <servlet>
- < servlet name
- > DatabaseAccess </ servlet name
- >
- < servlet class
- > DatabaseAccess </ servlet class
- >
- </ servlet >
- < servlet mapping
- >
- < servlet name
- > DatabaseAccess </ servlet name
- >
- < url pattern
- > /DatabaseAccess</ url pattern
- >
- </ servlet mapping
- >
- O/P :
- ID: 100, Age: 18, First: Zara, Last: Ali
- ID: 101, Age: 25, First: Mahnaz, Last: Fatma
- ID: 102, Age: 30, First: Zaid, Last: Khan
- ID: 103, Age: 28, First: Sumit, Last: Mittal
- 18. HTML Form and retrieving inputs using jsp
- What You'll Learn in This Hour:
- ● How to use a JSP to receive form data
- ● How to work with form parameters
- ● How servlets interact with forms
- ● How to use a single JSP to present a form and handle its submission
- By now you are probably comfortable with the fundamentals of JavaServer Pages and servlets. In the
- examples presented so far, you have learned how to send output back to the browser. One of the
- advantages of the Web is that you can create forms to send data from the browser to the server. You are
- finally ready to begin creating forms with JSP and servlets, and that's where the fun really begins!
- A Simple HTML Form
- To start off the exploration of HTML forms, it's best to start with a small form and expand from there. Also,
- it's better to start with a JSP rather than a servlet, because it is easier to write out the HTML. Most of the
- form handling for JSPs and servlets is identical, so after you know how to retrieve form information from a
- JSP, you know how to do it from a servlet. Listing 3.1 shows an HTML file containing a simple input form
- that calls a JSP to handle the form.
- Listing 3.1 Source Code for SimpleForm.html
- <html>
- <body>
- <h1>Please tell me about yourself</h1>
- <form action="SimpleFormHandler.jsp" method="get">
- Name: <input type="text" name="firstName">
- <input type="text" name="lastName"><br>
- Sex:
- <input type="radio" checked name="sex" value="male">Male
- <input type="radio" name="sex" value="female">Female
- <p>
- What Java primitive type best describes your personality:
- <select name="javaType">
- <option value="boolean">boolean</option>
- <option value="byte">byte</option>
- <option value="char" selected>char</option>
- <option value="double">double</option>
- <option value="float">float</option>
- <option value="int">int</option>
- <option value="long">long</option>
- </select>
- <br>
- <input type="submit">
- </form>
- </body>
- </html>
- The <form> tag in Listing 3.1 sends the input from the form to a JSP called SimpleFormHandler.jsp . Figure
- 3.1 shows this form running in a browser.
- Figure
- 3.1 HTML forms frequently serve as the front end for a JSP.
- The SimpleFormHandler JSP does little more than retrieve the form variables and print out their values.
- Listing 3.2 shows the contents of SimpleFormHandler.jsp , which you can see is pretty short.
- Listing 3.2 Source Code for SimpleFormHandler.jsp
- <html>
- <body>
- <%
- // Grab the variables from the form.
- String firstName = request.getParameter("firstName");
- String lastName = request.getParameter("lastName");
- String sex = request.getParameter("sex");
- String javaType = request.getParameter("javaType");
- %>
- <%Print
- out the variables. %>
- <h1>Hello, <%=firstName%> <%=lastName%>!</h1>
- I see that you are <%=sex%>. You know, you remind me of a
- <%=javaType%> variable I once knew.
- </body>
- </html>
- 19. JSP Tags’
- Tag handler class:
- A tag handler class should implement Tag / IterationTag / BodyTag interface or it can
- also extend TagSupport / BodyTagSupport / SimpleTagSupport class. All the classes
- that support custom tags are present inside javax.servlet.jsp.tagext . In the below
- we are extending the class SimpleTagSupport .
- Details.java
- package beginnersbook.com;
- import javax.servlet.jsp.tagext.*;
- import javax.servlet.jsp.*;
- import java.io.*;
- public class Details extends SimpleTagSupport {
- public void doTag() throws JspException , IOException {
- /*This is just to display a message, when
- * we will use our custom tag. This message
- * would be displayed
- */
- JspWriter out = getJspContext().getOut();
- out .println( "This is my own custom tag" );
- }
- }
- TLD File
- This file should present at the location: Project Name/WebContent/WEB‐INF/ and
- it should have a .tld extension.
- Note:
- <name> tag: custom tag name. In this example we have given it as MyMsg
- <tag‐class> tag: Fully qualified class name. Our tag handler class Details.java is in
- package beginnersbook.com so we have given the value as
- beginnersbook.com.Details .
- message.tld
- <taglib>
- <tlibversion>
- 1.0 </tlibversion>
- <jspversion>
- 2.0 </jspversion>
- <shortname>
- My Custom Tag </shortname>
- <tag>
- <name> MyMsg </name>
- <tagclass>
- beginnersbook.com.Details </tagclass>
- <bodycontent>
- empty </bodycontent>
- </tag>
- </taglib>
- Using custom tag in JSP:
- Above we have created a custom tag named MyMsg . Here we will be using it.
- Note: taglib directive should have the TLD file path in uri field. Above we have
- created the message.tld file so we have given the path of that file.
- Choose any prefix and specify it in taglib directive’s prefix field. Here we have
- specified it as myprefix .
- Custom tag is called like this: <prefix:tagName/> . Our prefix is myprefix and tag
- name is MyMsg so we have called it as <myprefix:MyMsg/> in the below JSP page.
- <%@ taglib prefix= "myprefix" uri= "WEBINF/
- message.tld" %>
- <html>
- <head>
- <title> Custom Tags in JSP Example </title>
- </head>
- <body>
- <myprefix:MyMsg/>
- </body>
- </html>
- Output:
- This is my own custom tag
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