iwp

Index.html file
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>GetPost</title>
</head>
<body>
<form name="frm1" method="get" action="getpostservlet">
username : <input type="text" name="uname">
<input type="submit" value="Submit">

</form>
</body>
</html>

Servlet code to print user name back to the user
package satish;

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;

/**
 * Servlet implementation class getpostservlet
 */

public class getpostservlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public getpostservlet() {
        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.setContentType("text/html");
		PrintWriter out = response.getWriter();
		out.print("welcome");
		String username = request.getParameter("uname");
		   out.print(username);

	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}


Servlet Code to print a table to the user

package satish;

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;

/**
 * Servlet implementation class getpostservlet
 */

public class getpostservlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public getpostservlet() {
        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.setContentType("text/html");
		PrintWriter out = response.getWriter();
		//writing a table to the user from servlet
		out.print("<table border=1>"
				+ "<tr><td>Name</td><td>Reg</td></tr>"
				+ "<tr><td>Satish</td><td>123</td></tr>"
				+ "<tr><td>Ram</td><td>124</td></tr>"
				+ "</table>"
				);

	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

Connecting to a database from within a servlet

HTML File
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>GetPost</title>
</head>
<body>
<form name="frm1" method="get" action="getpostservlet">
username : <input type="text" name="uname">
password : <input type="text" name="upass">
<input type="submit" value="Submit">

</form>
</body>
</html>


Servlet Code

package satish;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
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;

/**
 * Servlet implementation class getpostservlet
 */

public class getpostservlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public getpostservlet() {
        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.setContentType("text/html");
		PrintWriter out = response.getWriter();
		String uname = request.getParameter("uname");
		String password = request.getParameter("upass");
		 try
		 {
	      Connection con;
	      Class.forName("com.mysql.jdbc.Driver").newInstance();
	      con = DriverManager.getConnection("jdbc:mysql://localhost:3306/vit","root","");
	      Statement stmt = con.createStatement();
	      int i = stmt.executeUpdate("insert into user values ('"+uname+"','"+password+"')");
	      out.println("Record Inserted Successfully");
	      stmt.close();
	      con.close();
		 }
		 catch(SQLException | InstantiationException | IllegalAccessException | ClassNotFoundException e)
		 {
			 out.println(e.getMessage());
		 }

	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

Retrieving all Records from a database using servlet
package satish;

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;

/**
 * Servlet implementation class getpostservlet
 */

public class getpostservlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public getpostservlet() {
        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.setContentType("text/html");
		PrintWriter out = response.getWriter();
		String uname = request.getParameter("uname");
		String password = request.getParameter("upass");
		 try
		 {
	      Connection con;
	      Class.forName("com.mysql.jdbc.Driver").newInstance();
	      con = DriverManager.getConnection("jdbc:mysql://localhost:3306/vit","root","");
	      Statement stmt = con.createStatement();
	      ResultSet rs  = stmt.executeQuery("select * from user");
	      if(rs.next()==false)
	      {
	    	out.println("No Records in the table");
	      }
	      else
	      {
	         do
	          {
	        	 out.print(rs.getString(1));
	        	 out.print(rs.getString(2));
	          }while(rs.next());

	      }

	      stmt.close();
	      rs.close();
	      con.close();

		 }
		 catch(SQLException | InstantiationException | IllegalAccessException | ClassNotFoundException e)
		 {
			 out.println(e.getMessage());
		 }
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}