I am trying to call a java method('method1') that runs some r code(using RCaller) when a specific button is clicked on a JSP page('button1'), but when i click on the button it doesn't do anything and I am getting no errors in the output. I'm trying to use a servlet to run the java method from a JSP file. I'd appreciate any help.
Analysis.jsp:
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="style.css">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Analysis Page</title>
</head>
<body>
<center><h2>
Final year Prototype
</h2></center>
<center> <table border="0">
<thead>
<tr>
<th>Disabilities Analysis</th>
</tr>
</thead>
<tbody>
<tr>
<center><td></td></center>
</tr>
<tr>
<td>
<center>
Current HSE Support Centre Locations
</center>
</td>
</tr>
<tr>
<td>
<center>
New HSE Support Centre Locations
</center>
</td>
</tr>
<tr>
<td>
<center>
<form action="${pageContext.request.contextPath}/myservlet" method="POST">
<button type="submit" name="button" value="button1">Button 1</button>
<button type="submit" name="button" value="button2">Button 2</button>
<button type="submit" name="button" value="button3">Button 3</button>
</form>
</center>
</td>
</tr>
<tr>
<td>
<center>
Return
</center>
</td>
</tr>
</tbody>
</table></center>
</body>
</html>
myServlet.java:
package webJava;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet("/myservlet")
public class MyServlet extends HttpServlet {
#Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
TestMethods t = new TestMethods();
String button = request.getParameter("button");
if ("button1".equals(button)) {
t.method1();
} else if ("button2".equals(button)) {
t.method2();
} else if ("button3".equals(button)) {
t.method3();
} else {
}
request.getRequestDispatcher("/Analysis.jsp").forward(request, response);
}
}
TestMethods.java:
package webJava;
import java.io.File;
import javax.swing.ImageIcon;
import rcaller.RCaller;
import rcaller.RCode;
public class TestMethods {
public void method1() {
try {
RCaller caller = new RCaller();
RCode code = new RCode();
caller.setRscriptExecutable("/Library/Frameworks/R.framework/Versions/3.3/Resources/Rscript");
caller.cleanRCode();
caller.setRCode(code);
// load the ggplot2 library into R
code.R_require("ggplot2");
// create a data frame in R using x and y variables
code.addRCode("df <- data.frame(x,y)");
// plot the relationship between x and y
File file = code.startPlot();
code.addRCode("ggplot(df, aes(x, y)) + geom_point() + geom_smooth(method='lm') + ggtitle('y = f(x)')");
caller.runOnly();
ImageIcon ii = code.getPlot(file);
code.showPlot(file);
} catch (Exception e) {
System.out.println(e.toString());
}
}
public void method2() {
//some code
}
public void method3() {
//some code
}
}
My project directory:
Screenshot
Related
here I want to upload my file into my upload folder but in my scenario, it cannot store in that folder. The file name is printed in the console but the file does not store in the upload folder. In the Developer tool console, I get an error called Failed to load resource: the server responded with a status of 404 (Not Found).
DemoForm.java
package controller;
import java.io.*;
import java.util.* ;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
/**
* Servlet implementation class DemoForm
*/
#WebServlet("/DemoForm")
#MultipartConfig(
fileSizeThreshold = 1024 * 1024 * 10, //10MB
maxFileSize = 1024 * 1024 * 50, //50MB
maxRequestSize = 1024 * 1024 * 100 //100MB
)
public class DemoForm extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String UPLOAD_DIR = "upload";
/**
* #see HttpServlet#HttpServlet()
*/
public DemoForm() {
super();
// TODO Auto-generated constructor stub
}
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setAttribute("username", request.getParameter("username"));
request.setAttribute("password", request.getParameter("password"));
request.setAttribute("sex", request.getParameter("sex"));
request.setAttribute("favious", Arrays.toString(request.getParameterValues("favious")));
request.setAttribute("description", request.getParameter("description"));
request.setAttribute("experience", request.getParameter("experience"));
request.setAttribute("fileName", uploadFile(request));
request.getRequestDispatcher("form_result.jsp").forward(request, response);
}
private String uploadFile(HttpServletRequest request) {
String fileName = "";
try {
Part filePart = request.getPart("photo");
fileName = getfileName(filePart);
String applicationPath = request.getServletContext().getRealPath("");
String basePath = applicationPath + File.separator + UPLOAD_DIR
+ File.separator;
// creates the save directory if it does not exists
File fileSaveDir = new File(basePath);
if (!fileSaveDir.exists()) {
fileSaveDir.mkdir();
}
InputStream inputStream = null;
OutputStream outputStream = null;
try {
File outputFilePath = new File(basePath + fileName);
inputStream =filePart.getInputStream();
outputStream = new FileOutputStream(outputFilePath);
int read = 0;
final byte[] bytes = new byte[1024];
while((read = inputStream.read(bytes))!= -1) {
outputStream.write(bytes,0,read);
}
}catch(Exception ex) {
ex.printStackTrace();
fileName="";
}finally {
if(outputStream != null) {
outputStream.close();
}
if(inputStream != null) {
inputStream.close();
}
}
}catch(Exception ex){
fileName = "";
}
return fileName;
}
private String getfileName(Part part) {
final String partHeader = part.getHeader("content-disposition");
System.out.println("*****partHeader:" + partHeader);
for(String content : part.getHeader("content-disposition").split(";")) {
if(content.trim().startsWith("fileName")) {
return content.substring(content.indexOf('=')+ 1).trim()
.replace("\"", "");
}
}
return null;
}
}
Form.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Upload file</title>
</head>
<body>
<form method="post" action="DemoForm" enctype="multipart/form-data">
<table border="0" cellpadding="2" cellspacing="2" width="300">
<tr>
<td> username:</td>
<td><input type="text" name="username"/></td>
</tr>
<tr>
<td> Password:</td>
<td><input type="password" name="password"/></td>
</tr>
<tr>
<td valign="top"> Sex </td>
<td>
<input type="radio" name="sex" value="male" checked="checked"/>Male
<br>
<input type="radio" name="sex" value="female"/>Female
</td>
</tr>
<tr>
<td valign="top"> Favious </td>
<td>
<input type="checkbox" name="favious" value="fav1"/>Favios 1<br>
<input type="checkbox" name="favious" value="fav2"/>Favios 2<br>
<input type="checkbox" name="favious" value="fav1"/>Favios 3<br>
<input type="checkbox" name="favious" value="fav1"/>Favios 4<br>
<input type="checkbox" name="favious" value="fav1"/>Favios 5<br>
</td>
</tr>
<tr>
<td valign="top"> Description:</td>
<td><textarea rows="10" cols="20" name="description"></textarea></td>
</tr>
<tr>
<td>Experiences</td>
<td>
<select name="experience">
<option value="1"> 1 year </option>
<option value="2"> 2 year </option>
<option value="3"> 3 year </option>
<option value="4"> 4 year </option>
</select>
</td>
</tr>
<tr>
<td valign="top"> Photo</td>
<td><input type="file" name="photo "/></td>
</tr>
<tr>
<td> </td>
<td><input type="submit" name="save"/></td>
</tr>
</table>
</form>
</body>
</html>
Form_result.jsp
[<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%#page isELIgnored="false" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h3>Account Information</h3>
<table border="0" cellpadding="2" cellspacing="2" width="300">
<tr>
<td>Username</td>
<td> ${username}</td>
</tr>
<tr>
<td>Password</td>
<td> ${password}</td>
</tr>
<tr>
<td valign="top">Sex</td>
<td> ${sex}</td>
</tr>
<tr>
<td valign="top">Favious</td>
<td> ${favious}</td>
</tr>
<tr>
<td valign="top">Description</td>
<td> ${description}</td>
</tr>
<tr>
<td>Experience</td>
<td> ${experience}</td>
</tr>
<tr>
<td valign="top">Photo</td>
<td><img src="upload/${fileName}"></td>
</tr>
</table>
</body>
</html>][1]
I think the error is not in your file uploading. Your request has not been received by your servelet. Just comment out all the codes and check whether your doPost is working or not? Check the URL you are hitting.
The endpoint on which you are trying to upload the file is invalid.
Errorcode 404 means that the endpoint can not be found.
Here i've have 2 servlets
#WebServlet("/Login")
public class Login extends HttpServlet {
.........
.........
}
#WebServlet("/Create")
public class Create extends HttpServlet {
.........
.........
}
And a HTML page like this.
<form name="loginForm" method="post" action="Login">
<table width="20%" bgcolor="0099CC" align="center">
<tr>
<td colspan=2>
<center>
<font size=4><b>HTML Login Page</b></font>
</center>
</td>
</tr>
<tr>
<td>Username:</td>
<td><input type="text" size=25 name="username"></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="Password" size=25 name="password"></td>
</tr>
<tr>
<td><input type="submit" onclick="return check(this.form)" value="Login"></td>
</tr>
<tr>
<td><input type="submit" onclick="return check(this.form)" value="Create profile"></td>
</tr>
</table>
</form>
I want to redirect to Create servlet when the user clicks on create profile. Can anyone help me with this?
You need to select the action based on the button which is clicked. You can do it using JavaScript. Given below is the minimal, working example which you can extend as per your requirement:
HTML
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<script>
function check(form, button){
if(button.id=='login'){
form.action="Login";
}else if(button.id=='create'){
form.action="Create";
}
form.submit();
}
</script>
<title>Insert title here</title>
</head>
<body>
<form name="loginForm" method="post">
<table width="20%" bgcolor="0099CC" align="center">
<tr>
<td colspan=2>
<center>
<font size=4><b>HTML Login Page</b></font>
</center>
</td>
</tr>
<tr>
<td>Username:</td>
<td><input type="text" size=25 name="username"></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="Password" size=25 name="password"></td>
</tr>
<tr>
<td><input type="button" id="login" onclick="check(this.form,this)"
value="Login"></td>
</tr>
<tr>
<td><input type="button" id="create" onclick="check(this.form,this)"
value="Create profile"></td>
</tr>
</table>
</form>
</body>
</html>
Login.java
package servlets;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet("/Login")
public class Login extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
out.println("Login");
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
}
Create.java
package servlets;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet("/Create")
public class Create extends HttpServlet{
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
out.println("Create");
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
}
You have one form and you want it to go to two different servlet. You can't do that. If you want to goto login servlet first and then goto create servlet. You can do that view requestDispatcher or httpServletresponse.sendRedirect()
RequestDispatcher rd=request.getRequestDispatcher("servlet Name")
rd.forward(request, response);
or by
response.sendRedirect("/url");
Or if you dont want to go the login servlet at all and directly want to go to create then use two forms one for your Login and another one for your Create Profile.
<form name="loginForm" method="post" action="Create">
<tr>
<td><input type="submit" onclick="return check(this.form)" value="Create profile"></td>
</tr>
I have a DynamicWebApp in Eclipse with Tomcat Apache.
My task: The bean consists of 2 operands of type Integer and as text the arithmetic operations Addition with '+', Subtraction with '-' and Multiplication with 'MUL'. The bean returns the calculation result of type Integer. Then implement the following two scenarios:
Scenario 1: Implement a suitable Java Servlet that calls the Java Bean. You call the servlet using your own HTML page.
Scenario 2: Implement a suitable Java server page that reuses the Java bean using JSP standard actions. Then call your bean from the JSP page.
html opens and i can calculate. after submit nothing opens but i can see in the browser url what i wrote.
and if i start the jsp than i get: cannot find any information on property (firstNum) in a bean of type (bean.CalculatorBean)
my html code called: index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Hallo Welt</title>
</head>
<body>
<form action="HalloServlet" method="get" style="text-align: center">
<table border="1" width="25%">
<tr style="text-align: center">
<td colspan="2">Rechner</td>
<td></td>
</tr>
<tr>
<td>Zahl 1</td>
<td><input type="text" name="firstNum"></td>
</tr>
<tr>
<td>Operator</td>
<td><select name="operator">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">MUL</option>
</select></td>
</tr>
<tr>
<td>Zahl 2</td>
<td><input type="text" name="secondNum"></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="="></td>
</tr>
</table>
</form>
</body>
</html>
servlet called: HalloServlet.java
package calculator;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import bean.CalculatorBean;
#WebServlet("/HalloServlet")
public class HalloServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
// Get Parameter from index.html
int operand1 = Integer.parseInt(request.getParameter("firstNum"));
int operand2 = Integer.parseInt(request.getParameter("secondNum"));
char operator1 = request.getParameter("operator").charAt(0);
// Parameter from HalloServlet.java to CalculatorBean
CalculatorBean.setFirstNum(operand1);
CalculatorBean.setSecondNum(operand2);
CalculatorBean.setOperator(operator1);
// Parameter from CalculatorBean to HalloServlet.java
CalculatorBean.getFirstNum();
CalculatorBean.getSecondNum();
CalculatorBean.getOperator();
int i = Integer.parseInt(request.getParameter("result"));
PrintWriter out = response.getWriter();
out.println(i);
out.flush();
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
}
bean called: CalculatorBean.java
package bean;
public class CalculatorBean {
private int firstNum;
private int secondNum;
private char operator = '+';
private int result;
public static void getFirstNum() {
}
public static void setFirstNum(int firstNum) {
}
public static void getSecondNum() {
}
public static void setSecondNum(int secondNum) {
}
public static void getOperator() {
}
public static void setOperator(char operator) {
}
public int getResult() {
return result;
}
public void setResult(int result) {
this.result = result;
}
public void calculate() {
switch (this.operator) {
case '+': {
this.result = this.firstNum + this.secondNum;
break;
}
case '-': {
this.result = this.firstNum - this.secondNum;
break;
}
case '*': {
this.result = this.firstNum * this.secondNum;
break;
}
}
}
}
jsp called: HalloJSP.jsp
<%# page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body>
<jsp:useBean id="CalculatorBean" class="bean.CalculatorBean">
</jsp:useBean>
<jsp:setProperty name="CalculatorBean" property="*" />
<%
CalculatorBean.calculate();
%>
<br />
<hr>
<br /> Ergebnis:
<jsp:getProperty name="CalculatorBean" property="firstNum" />
<jsp:getProperty name="CalculatorBean" property="operator" />
<jsp:getProperty name="CalculatorBean" property="secondNum" />
=
<jsp:getProperty name="CalculatorBean" property="result" />
<br />
<hr>
<br />
<form action="HalloJSP.jsp" method="post" style="text-align: center">
<table border="1" width="25%">
<tr style="text-align: center">
<td colspan="2">Rechner</td>
<td></td>
</tr>
<tr>
<td>Zahl 1</td>
<td><input type="text" name="firstNum"></td>
</tr>
<tr>
<td>Operator</td>
<td><select name="operator">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">MUL</option>
</select></td>
</tr>
<tr>
<td>Zahl 2</td>
<td><input type="text" name="secondNum"></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="="></td>
</tr>
</table>
</form>
</body>
</html>
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
<display-name>hallowelt</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
You should have noticed that your implementation contains empty methods?
public static void setFirstNum (int firstNum) {
}
Best to create new bean! Right click on "src" or beanpackage.
Then click New -> Class. Give the bean a name and click on "add" at interface. In the following window enter "Serializable" and add purple serializable interface ...
Create attributes. mark this, right click -> source -> generate getter and setter!
Implement an empty constructor such as CalcBean () {}
implement in the setResult calculator. everything else is superfluous
servlet
do right click on your source folder or httpservlet package -> new -> servlet. name it -> click on doGet and make doPost -> Finito ... copy your stuff from open script "2 java servlets.pdf" necessarily via pdf-Reader! Go to page 23.
Mark the whole flow within the doGet method COMPLETE. Put that in your servlet. Replace the getter methods of your bean with:
o.println ("<p> number 1:" + beans.getFirstNummero () ...
open script in pdf reader, because then the formatting is inserted correctly formatted when "inserting" the script copy (therefore do not open pdf via browser, otherwise haste a single line when inserting)
What surprised me is that many have answered many, even though you have more code and almost everything completely specified and the error regarding the bean everyone should have noticed here ...
In the future, be a bit more curious while working in Eclipse ... everywhere, make a right-click and see what eclipse can do. Via plugins goes even more, but meanwhile Eclipse in contrast to android studio is better. that android studio is more intended for android code
I have LoginServlet like this:
package servlets;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
if (username.equals("gogikole") && password.equals("1234")) {
response.sendRedirect("mainMenu.jsp");
return;
}
}
}
And login.jsp like this:
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Login page</title>
</head>
<body>
<form method="post" action="LoginServlet"></form>
<table>
<tr>
<td>User name</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>Password</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="Login"></td>
</tr>
</table>
</body>
</html>
For some reason when I input correct username: (gogikole) and password: (1234) and click on submit button it won't to redirect me to mainMenu.jsp
When I click on button, nothing happen it just stay on login page like I didn't even click or type anything.
How to fix that problem and redirect when I click on submit button (Login)?
I created mainMenu.jsp and, for now that is one allmost blank page only with message "Welcome".
Your submit button is not submitting the form.
i.e., you have closed the form immediately:
<form method="post" action="LoginServlet"></form>
The problem is that your form inputs and submit button are outside the form You have to enclose as below.
<form method="post" action="LoginServlet">
<table>
<tr>
<td>User name</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>Password</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="Login"></td>
</tr>
</table>
</form>
hi all I have a LoginServlet that has the functionality to log in a user however I have a jsp page with the styling I'd to use. I am unsure how I can use the functionality from my LoginServlet in my login.jsp
here is the entirety of my code for the LoginServlet, I am aware I have coded to display a page but I need to use this jsp page to display. This is a uni assignment I have been given and it's part of the requirement that we use JSP for display.
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.RequestDispatcher;
/**
* Servlet implementation class LoginServlet
*/
#WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* #see HttpServlet#HttpServlet()
*/
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}
private void sendLoginForm(HttpServletResponse response,
boolean withErrorMessage)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Login</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<CENTER>");
if (withErrorMessage)
out.println("Login failed. Please try again.<BR>");
out.println("<BR>");
out.println("<BR><H2>Login Page</H2>");
out.println("<BR>");
out.println("<BR>Please enter your user name and password.");
out.println("<BR>");
out.println("<BR><FORM METHOD=POST>");
out.println("<TABLE>");
out.println("<TR>");
out.println("<TD>User Name:</TD>");
out.println("<TD><INPUT TYPE=TEXT NAME=uniid></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Password:</TD>");
out.println("<TD><INPUT TYPE=PASSWORD NAME=password></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD ALIGN=RIGHT COLSPAN=2>");
out.println("<INPUT TYPE=SUBMIT VALUE=Login></TD>");
out.println("</TR>");
out.println("</TABLE>");
out.println("</FORM>");
out.println("</CENTER>");
out.println("</BODY>");
out.println("</HTML>");
}
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
sendLoginForm(response, false);
}
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String uniid = request.getParameter("uniid");
String password = request.getParameter("password");
if (login(uniid, password)) {
/*RequestDispatcher rd =
request.getRequestDispatcher("AnotherServlet");
rd.forward(request, response); */
response.sendRedirect("home_student.jsp");
}
else {
sendLoginForm(response, true);
}
}
boolean login(String uniid, String password) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/wae","root","");
System.out.println("got connection");
Statement s = con.createStatement();
String sql = "SELECT uniid FROM user" +
" WHERE uniid='" + uniid + "'" +
" AND password='" + password + "'";
ResultSet rs = s.executeQuery(sql);
if (rs.next()) {
return true;
}
rs.close();
s.close();
con.close();
}
catch (ClassNotFoundException e) {
System.out.println(e.toString());
}
catch (SQLException e) {
System.out.println(e.toString());
}
catch (Exception e) {
System.out.println(e.toString());
}
return false;
}
}
here is my jsp page
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Mars University Lab System</title>
<link rel="stylesheet" href="style.css" type="text/css" media="screen">
</head>
<body>
<jsp:include page="header.jsp"/>
<tr>
<td>
</td>
</tr>
<tr>
<td>
<div id = "centrecontent">
<table border="0" cellpadding="2">
<tr>
<td width="500px" align="center">
<br>
<font size="5">Welcome to <i>The Department of <br>Rocket Science</i> Lab System<br></font>
<br>
For <b>Students</b> you can enrol in labs<br> and manage the labs you're enrolled in.<br><br>
For <b>Tutors</b> you can view the labs<br> you're teaching and record attendence.<br><br>
For <b>Lecturers</b> you can create and<br> manage lab classes, register Tutors and<br> assign those Tutors to labs.<br><br>
</td>
<td width="500px">
<table border="0" align="center">
<tr>
<td align="center">
<table border="0" align="center">
<tr> <br><br><b>Existing Member? <br>Sign In Here!</b><br>
<td align="right">
<form name ="login" METHOD=POST ACTION="SaveSession.jsp">
Username: <input type="text" name="username"/><br />
Password: <input type="password" name="pword"/><br />
<input type=SUBMIT value="Login" name="Submit" />
</td>
</tr>
</table>
<br><br><br><br>
<form name="search_cat_bar" method="get" action="">
<input type="hidden" name="dff_view" value="grid">
Search:<input type="text" name="dff_keyword" size="30" maxlength="50"> <br>in
<select name="dff_cat1num" size="1">
<option value="-1">All Subjects
<option value="-2">--------------
<option value="101">CSE2ICE
<option value="193">CSE3PRA
<option value="193">CSE3PRB
<option value="193">CSE3WAE
</select>
<input type="submit" value="Find">
</form>
</td>
</tr>
</table>
</td>
</tr>
</table>
<table>
<tr>
</tr>
</table>
</div>
<jsp:include page="footer.jsp"/>
</body>
</html>
I'd like the login.jsp page to call my LoginServlet for the login functions.
You can call servlet by this way:
web.xml
<servlet>
<servlet-name>UserLogin</servlet-name>
<servlet-class>com.servlet.LoginServlet</servlet-class>//full class path
</servlet>
<servlet-mapping>
<servlet-name>UserLogin</servlet-name>
<url-pattern>/servlet/login</url-pattern>
</servlet-mapping>
login.jsp
<form name="login" action="<%=request.getContextPath()%>/servlet/login" method="post">
</form>
Servlet:
Login check and also you can send just error message to login page and display message like,
res.sendRedirect(req.getContextPath()+"/webpages/login.jsp?login=failed");
And in login.jsp you can retrieve parameter request.getParameter("login") and display proper message
add action in the html form tag.
action is LoginServlet URL.
It's easier to have the standard way of doing this:
Have jsp page with a form, to receive inputs from the user.
Have a servlet to process the data.
If there is a problem, set an error message and redirect the user to the login page. Otherwise redirect him to the destination.
Do not forget to set your form's action the address of your servlet.