Java Tutorial/Servlet/Form

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Get Form Text Field as a Servlet parameter

   <source lang="java">

import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class MyServlet extends HttpServlet { 

 public void doGet(HttpServletRequest req, HttpServletResponse res)
                              throws ServletException, IOException {
   res.setContentType("text/html");
   PrintWriter out = res.getWriter();
   String name = req.getParameter("name");
   out.println("<HTML>");
   out.println("<HEAD><TITLE>Hello, " + name + "</TITLE></HEAD>");
   out.println("<BODY>");
   out.println("Hello, " + name);
   out.println("</BODY></HTML>");
 }
 public String getServletInfo() {
   return "A servlet that knows the name of the person to whom it"s" + 
          "saying hello";
 }

}</source>





Servlet Based GuestBook

   <source lang="java">

import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.util.*; public class MyServlet extends HttpServlet { 

 private Vector entries = new Vector();  
 private long lastModified = 0;          
 
 public void doGet(HttpServletRequest req, HttpServletResponse res) 
                              throws ServletException, IOException {
   res.setContentType("text/html");
   PrintWriter out = res.getWriter();
   printHeader(out);
   printForm(out);
   printMessages(out);
   printFooter(out);
 }
 // Add a new entry, then dispatch back to doGet()
 public void doPost(HttpServletRequest req, HttpServletResponse res) 
                               throws ServletException, IOException {
   handleForm(req, res);
   doGet(req, res);
 }
 private void printHeader(PrintWriter out) throws ServletException {
   out.println("<HTML><HEAD><TITLE>Guestbook</TITLE></HEAD>");
   out.println("<BODY>");
 }
 private void printForm(PrintWriter out) throws ServletException {
   out.println("<FORM METHOD=POST>");  // posts to itself
   out.println("Please submit your feedback:
");
   out.println("Your name: <INPUT TYPE=TEXT NAME=name>
");
   out.println("Your email: <INPUT TYPE=TEXT NAME=email>
");
   out.println("Comment: <INPUT TYPE=TEXT SIZE=50 NAME=comment>
");
   out.println("<INPUT TYPE=SUBMIT VALUE=\"Send Feedback\">
");
   out.println("</FORM>");
out.println("
"); 
 }
 private void printMessages(PrintWriter out) throws ServletException {
   String name, email, comment;
   Enumeration e = entries.elements();
   while (e.hasMoreElements()) {
     GuestbookEntry entry = (GuestbookEntry) e.nextElement();
     name = entry.name;
     if (name == null) name = "Unknown user";
     email = entry.email;
     if (name == null) email = "Unknown email";
     comment = entry.rument;
     if (comment == null) comment = "No comment";
out.println("
"); out.println("
" + name + " (" + email + ") says"); out.println("
" + comment + "
"); out.println("
"); 
     // Sleep for half a second to simulate a slow data source
     try { Thread.sleep(500); } catch (InterruptedException ignored) { }
   }
 }
 private void printFooter(PrintWriter out) throws ServletException {
   out.println("</BODY>");
 }
 private void handleForm(HttpServletRequest req,
                         HttpServletResponse res) {
   GuestbookEntry entry = new GuestbookEntry();
   entry.name = req.getParameter("name");
   entry.email = req.getParameter("email");
   entry.rument = req.getParameter("comment");
   entries.addElement(entry);
   // Make note we have a new last modified time
   lastModified = System.currentTimeMillis();
 }
 public long getLastModified(HttpServletRequest req) {
   return lastModified;
 }

} class GuestbookEntry { 

 public String name;
 public String email;
 public String comment;

}</source>





Servlet Form Processor CheckBox

   <source lang="java">

import javax.servlet.http.*; import javax.servlet.*; import java.io.IOException; public class MyServlet extends HttpServlet { 

 public void doPost (HttpServletRequest req, HttpServletResponse res) throws IOException
 {
   ServletOutputStream out = res.getOutputStream();
   res.setContentType("text/html");
   out.println("<html><head><title>Basic Form Processor Output</title></head>");
   out.println("<body>");
out.println("

Here is your Form Data

"); 
   //extract the form data here
   String title = req.getParameter("title");
   String name = req.getParameter("name");
   String city = req.getParameter("city");
   String country = req.getParameter("country");
   String tel = req.getParameter("tel");
   String age = req.getParameter("age");
   // extracting data from the checkbox field
   String[] interests = req.getParameterValues("interests");
   //output the data into a web page
   out.println("Your title is "  + title);
   out.println("
Your name is "  + name);
   out.println("
Your city is "  + city);
   out.println("
Your country is "  + country);
   out.println("
Your tel is "  + tel);
out.println("
Your interests include
    "); for (int i=0;i<interests.length; i++) { out.println("
  • " + interests[i]); } out.println("
"); 
 out.println("
Your age is "  + age);
   out.println("</body></html>");
 }

}</source>





Servlet Post Form Data to Self Servlet

   <source lang="java">

import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.util.*; public class MyServlet extends HttpServlet { 

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, java.io.IOException {
 System.out.println("command: "+request.getParameter("command"));
   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   out.println("<html><head>");
   out.println("<title>Help Page</title></head><body>");
out.println("

Please submit your information

"); 
   out.println("<form method=\"post\" action =\"" + request.getContextPath() +"/MyServlet\" >");
out.println(""); out.println("
"); out.println("Your first name: "); 
   out.println("<input type=\"text\" name=\"firstname\" size=\"20\">");
out.println("
"); out.println("Your last name: "); 
   out.println("<input type=\"text\" name=\"lastname\" size=\"20\">");
out.println("
"); out.println("Your email: "); 
   out.println("<input type=\"text\" name=\"email\" size=\"20\">");
out.println("
"); out.println("<input type=\"submit\" value=\"Submit Info\">
</form>"); 
   out.println("</body></html>");
    }
  public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException,java.io.IOException{
 Enumeration paramNames = request.getParameterNames();
 String parName;
 boolean emptyEnum = false;
 if (! paramNames.hasMoreElements())
     emptyEnum = true;

   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   out.println("<html><head>");
   out.println("<title>Submitted Parameters</title></head><body>");
 if (emptyEnum){
out.println("

Sorry, the request does not contain any parameters

"); 
 } else {
out.println("

Here are the submitted parameter values

"); 
 }
 while(paramNames.hasMoreElements()){
     parName = (String) paramNames.nextElement();
     out.println("" + parName + " : " + request.getParameter(parName));
     out.println("
");
 }
 out.println("</body></html>");
 }

}</source>


Источник — «http://jexp.ru/index.php?title=Java_Tutorial/Servlet/Form&oldid=4902»