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Servlets

weird functioning of servlet

adeeb alexander

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posted 12 years ago

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Hi.

First i will paste all my code here.

DataPage.jsp

DataServlet.java

import java.io.*;

import java.util.*;

import java.sql.*;

import javax.servlet.*;

import javax.servlet.http.*;

public class DataServlet extends HttpServlet{

private ServletConfig config;

//Setting JSP page
String page="DataPage.jsp";
public void init(ServletConfig config)  throws ServletException{

this.config=config;

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException,IOException
{

PrintWriter out = response.getWriter();

//Establish connection to MySQL database

String connectionURL = "jdbc:mysql://localhost:3306/jsp";

Connection connection= null;

ResultSet rs;

response.setContentType("text/html");

List dataList = new ArrayList();

try {

// Load the database driver

Class.forName("com.mysql.jdbc.Driver");

// Get a Connection to the database

connection = DriverManager.getConnection(connectionURL, "root", "bismillah");

//Select the data from the database

//String sql = "select * from users";

PreparedStatement ps = connection.prepareStatement("select * from users");

rs = ps.executeQuery();

while (rs.next ()){

//Add records into data list

dataList.add(rs.getString("name"));

dataList.add(rs.getString("passwrd"));
  dataList.add(rs.getString("type"));

}

rs.close ();

ps.close ();

}catch(Exception e){

System.out.println("Exception is ;"+e);

}

request.setAttribute("data",dataList);

//Disptching request

RequestDispatcher dispatcher = request.getRequestDispatcher(page);

if (dispatcher != null){

dispatcher.forward(request, response);

}

This two are dependent on each other, wright? I have other jsp page which is dependent on other servlet. Code is below

Insert.jsp

Insert.java

import java.io.*;

import java.util.*;

import java.sql.*;

import javax.servlet.*;

import javax.servlet.http.*;

public class Insert extends HttpServlet{

public void doPost(HttpServletRequest req, HttpServletResponse res)

throws ServletException,IOException
{

PrintWriter out = res.getWriter();

//Establish connection to MySQL database

String connectionURL = "jdbc:mysql://localhost:3306/jsp";

Connection connection= null;

ResultSet rs;

res.setContentType("text/html");

try {

// Load the database driver

Class.forName("com.mysql.jdbc.Driver");

// Get a Connection to the database

connection = DriverManager.getConnection(connectionURL, "root", "bismillah");

//Select the data from the database
	String name=req.getParameter("name");
		String pwd=req.getParameter("pwd");
		String type=req.getParameter("type");
  //String sql = "select * from users";

PreparedStatement ps=connection.prepareStatement("INSERT INTO users VALUES(?,?,?)");
			ps.setString(1,name);
			ps.setString(2,pwd);
			ps.setString(3,type);
		//	ps.executeUpdate();
			ps.close();
			connection.close();
			
		//	res.sendRedirect("./Insert.jsp");

req.setAttribute("message","Inserted one row");

//Disptching request

RequestDispatcher dispatcher = req.getRequestDispatcher("/Insert.jsp");

if (dispatcher != null){
	
	  dispatcher.forward(req, res);
	
	  }

}catch(Exception e){

System.out.println("Exception is ;"+e);

}

Now. The insert.jsp works fine, when I give data and click add button, the database is also updated. Till here its fine

THE PROBLEM:
In DataPage.jsp I am viewing the list sent by the servlet "DataServlet". So if i run the DataPage.jsp directly I get an error at the itterator. However, I accessed the DataServlet from the browser then i get this error "HTTP method GET is not supported by this URL" which i used to not get in the beginning. This started after I added the Insert.jsp and Insert.java files. I am unable to solve it. Someone please point out the problem.

Thanks and regards
Adeeb

adeeb alexander

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Posts: 268

posted 12 years ago

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Hey i missed this point. I tried to access DataServlet from different jsp file using a submit button and form with method as post and all.. Here the URL Shows up with /mypath/DataServlet. But the most annoying thing is its not behaving as it should i.e displaying database table by redirecting to DataPage.jsp, as the code is written, instead it shows the window of same Insert. NOTE:In URL name is DataServlet, but it shows Insert page. How come??? I restarted Apche many times, recompiled the code. Dont know the problem. Please help me out.

Thanks.

Bear Bibeault

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posted 12 years ago

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adeeb alexander wrote:In URL name is DataServlet, but it shows Insert page. How come?

You are forwarding from the servlet to the JSP. So why is this a surprise? It's doing exactly what you told it to do.

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adeeb alexander

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Posts: 268

posted 12 years ago

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The problem is I dint know about xml tags. I wrote like this
<servlet>
<servlet-name>DataServlet</servlet-name>
<servlet-class>DataServlet</servlet-class>

<servlet-name>Insert</servlet-name>
<servlet-class>Insert</servlet-class>
</servlet>

instead of writing individually.
I was surprised cauz, even the URL was wright, but page displayed was different..
Now its resolved. Thanks.

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