how to create insert, update, delete buttons on the same page?

[Punit Jain]

i created a program which has three classes, my program is inserting, updating, deleting, fetching records from database, and my code is working perfectly for me, but i created this for console:

Here is my three classes:
EmpDbComponent.java

import java.sql.*;
public class EmpDbComponent {
public ResultSet fetchRecords(Connection conn) throws SQLException, ClassNotFoundException
{
String query = "SELECT * FROM employee";
Statement st =conn.createStatement();
ResultSet rs = st.executeQuery(query);
	return rs;
}
public int insertRecords(Connection conn, Employee emp) throws ClassNotFoundException, SQLException
{
	String query = "INSERT INTO employee VALUES ("+emp.getId()+",'"+emp.getEmp_Name()+"','"+emp.getEmp_Designation()+"',"+emp.getEmp_Salary()+")";
	Statement st = conn.createStatement();
	int rs = st.executeUpdate(query);
	return rs;
}
public int updateRecord(Connection conn, Employee emp) throws ClassNotFoundException, SQLException
{
	String query = "UPDATE employee SET emp_name ='"+emp.getEmp_Name()+"', emp_salary = "+emp.getEmp_Salary()+", emp_designation = '"+emp.getEmp_Designation()+"' WHERE emp_id = "+emp.getId()+"";
	Statement st = conn.createStatement();
	int rs = st.executeUpdate(query);
	return rs;
}
public int deleteRecord(Connection conn, Employee emp) throws ClassNotFoundException, SQLException
{
	String query = "DELETE FROM employee WHERE emp_id = '"+emp.getId()+"'";
	Statement st = conn.createStatement();
	int rs = st.executeUpdate(query);
	return rs;
}
}

Employee.java

public class Employee {
	private int id;
	private String emp_Name;
	private String emp_Designation;
	private Double emp_Salary;
	Employee()
	{
	}
	Employee(int id)
	{
		this.id = id;
	}
	Employee(int id, String emp_name, Double emp_salary,String emp_designation)
	{
		this.id = id;
		this.emp_Name = emp_name;
		this.emp_Designation = emp_designation;
		this.emp_Salary = emp_salary;
	}
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getEmp_Name() {
		return emp_Name;
	}
	public void setEmp_Name(String emp_Name) {
		this.emp_Name = emp_Name;
	}
	public String getEmp_Designation() {
		return emp_Designation;
	}
	public void setEmp_Designation(String emp_Designation) {
		this.emp_Designation = emp_Designation;
	}
	public Double getEmp_Salary() {
		return emp_Salary;
	}
	public void setEmp_Salary(Double emp_Salary) {
		this.emp_Salary = emp_Salary;
	}

}

Test.java

import java.sql.Connection;
import java.util.Scanner;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
class choices
{
	private int id;
	private String name;
	private Double salary;
	private String designation;
	Scanner sc = new Scanner(System.in);
	boolean isAgain = true;
	int ch;
	Employee em = new Employee();
	public void InsertMethod()
	{
		System.out.println("Enter Employee Id: ");
		id = sc.nextInt();
		em.setId(id);
		System.out.println("Enter Employee Name: ");
		name = sc.next();
		em.setEmp_Name(name);
		System.out.println("Enter Employee Salary: ");
		salary = sc.nextDouble();
		em.setEmp_Salary(salary);
		System.out.println("Enter Employee Designation");
		designation = sc.next();
		em.setEmp_Designation(designation);
	}
	public void UpdateMethod()
	{
		System.out.println("Enter Employee Id whose record you want to update: ");
		id = sc.nextInt();
		em.setId(id);
		System.out.println("Enter Employees new Name whose id is:"+id);
		name = sc.next();
		em.setEmp_Name(name);
		System.out.println("Enter Employees new  Salary whose id is:"+id);
		salary = sc.nextDouble();
		em.setEmp_Salary(salary);
		System.out.println("Enter Employees new Designation whose id is"+id);
		designation = sc.next();
		em.setEmp_Designation(designation);
	}
	public void DeleteMethod()
	{
		System.out.println("Enter Employee Id whose record you want to Delete: ");
		id = sc.nextInt();
	}
	public boolean askAgain()
	{
		System.out.println("Press 1 to display menu again, press any other key to exit");
		ch = sc.nextInt();
		if(ch == 1)
			return true;
		else 
			return false;
	}
	public void choice() throws ClassNotFoundException, SQLException
	{
		do
		{
			try
			{
			int choice;
			Test t = new Test();
			EmpDbComponent db = new EmpDbComponent();
			ResultSet rs;
			System.out.println("Enter you choice\n 1.>Press 1 to Display \n 2.>Press 2 to Insert \n 3.> Press 3 to Update \n 4.> press 4 to Delete\n 5.> Press 5 to Exit\n");
			choice = sc.nextInt();
			switch(choice)
			{
				case 1:
				{
					System.out.println("---\t\t-----\t\t-------\t\t--------------");
					System.out.println("Id\t\t Name\t\t Salary\t\t Designation");
					System.out.println("---\t\t-----\t\t-------\t\t--------------");
					rs = db.fetchRecords(t.getConnection());
					while(rs.next())
					{
					System.out.print(rs.getInt(1)+"\t\t");
					System.out.print(rs.getString(2)+"\t\t");
					System.out.print(rs.getInt(3)+"\t\t");
					System.out.println(rs.getString(4));
					}
					break;
				}
				case 2:
				{
					InsertMethod();
					Employee emp = new Employee(id,name,salary,designation);
					int i = db.insertRecords(t.getConnection(), emp);
					if(i == 0)
						System.out.println("Not inserted successfully");
					else
						System.out.println("Inserted Successfully");
					break;
				}
				case 3:
				{
					UpdateMethod();
					Employee emp = new Employee(id);
					int i = db.updateRecord(t.getConnection(), emp);
					if(i == 0)
						System.out.println("Not Updated Succesfully");
					else
						System.out.println("Congratulation your record is updated Successfully");
					break;
				}
				case 4:
				{
					DeleteMethod();
					Employee emp = new Employee(id,name,salary,designation);
					int i = db.deleteRecord(t.getConnection(), emp);
					if(i == 0)
						System.out.println("Not Deleted Succesfully");
					else
						System.out.println("Deleted Successfully");
					break;
				}
				case 5:
				{
					System.exit(0);
				}
				default:
				{
					System.out.println("Your Choice is not from the given list..");
					break;
				}
			
			}isAgain = askAgain();
			}
			catch(Exception e)
			{
				e.printStackTrace();
			}
		}while(isAgain);
	}
}

public class Test {
	public Connection getConnection() throws ClassNotFoundException, SQLException 
	{
	/* for type 4 drivers */
		
	String user = "root";
	String pass = "";
	String url = "jdbc:mysql://localhost/javapractices";
	String conn = "com.mysql.jdbc.Driver";
	Class.forName(conn);
	Connection con= DriverManager.getConnection(url,user,pass);
	
	/* end of connection */
		
	return con;
	}
	public static void main(String args[]) throws SQLException, ClassNotFoundException
	{
		choices ch = new choices();
		ch.choice();
	}
}

now what i want is i create a from in html, for these employee records and i have three buttons on the same page (ie. Insert, Update, Delete) how do i call functions of my EmpDbComponent class on each button click..?? all three buttons are on the same form..

[Wendy L Gibbons]

Have you ever written a jsp page before?

if you have made many jsps before what exact problem are you having? if not can I recommend the head first servlets and jsp book, it is a modern classic.

[Punit Jain]

i am using servlet here, and the problem is i don't know how to i pass one function of one servlet as a of one button click,
for a single button i just create a from and on the action i pass that servlet. but for multiple buttons how do i do this, although i have same form on my page...

[Punit Jain]

my question is simply how can i add multiple buttons (ie.add/update/delete) in my form, in which i can use functions of EmpDbComponent on each button call
Test.java is i use for console, but now i m using servlet
here is my servlet i am using for these operations

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

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Employee_Operations
 */
public class Employee_Operations extends HttpServlet {
	private static final long serialVersionUID = 1L;
    
    public Connection getConnection() throws ClassNotFoundException, SQLException 
	{
			
	String user = "root";
	String pass = "";
	String url = "jdbc:mysql://localhost/javapractices";
	String conn = "com.mysql.jdbc.Driver";
	Class.forName(conn);
	Connection con= DriverManager.getConnection(url,user,pass);
	return con;
	}
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		String id1 = request.getParameter("emp_id");
		int id = Integer.parseInt(id1); 
		String name = request.getParameter("emp_name");
		String salary1 = request.getParameter("emp_salary");
		int salary = Integer.parseInt(salary1);
		String designation = request.getParameter("emp_designation");
		Employee emp = new Employee(id,name,designation,salary);
		EmpDbComponent db = new EmpDbComponent();
		try {
			db.insertRecords(getConnection(), emp);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		emp.setId(id);
		emp.setEmp_Name(name);
		emp.setEmp_Designation(designation);
		emp.setEmp_Salary(salary);
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		out.println("<p>Id is: "+id+"</p>");
		out.println("<p>Name is: "+name+"</p>");
		out.println("<p>Salary is is: "+salary+"</p>");
		out.println("<p>Designation is is: "+designation+"</p>");
		out.close();
	}
}

and this servlet i am calling on a form submit, and i want to perform more operations on the same form, not only displaying how can i do this??

[J. Kevin Robbins]

If I'm understanding your question correctly, one possibility is to assign names to your buttons. Upon form submit, the name of the button will be passed as one of the form parameters and you can use that in the servlet to determine which button was clicked.

Myself, I would use JavaScript to catch the click events and use AJAX to perform the CRUD operations.

[Punit Jain]

well i don't know how to do this with ajax and javascript...
and okay, i assign names to my three buttons, how my servlet will know which button is pressed and which function needs to invoke..??
what i need to do for this??

[Kumaravadivel Subramani]

Any request which hits servlet, will be processed by get() or post() which is depends on your form submit method. You have to set a html element to indicate which element has been clicked(this is very basis idea to use)so that it would send to servlet as a parameter. Based on the flag you can process call your method.

[J. Kevin Robbins]

The name and value of the button that is clicked will be passed as a request parameter. Look at the docs for request.getParameterNames(). Loop through that enumeration checking for your button names and branch accordingly.

[Bear Bibeault]

The button mane will be part of the request parameters.

Wendy is correct. You need to go back and do some reading. This sort of thing is a very basic concept in JSP and servlets and will be covered in any good book on the subject.

[Punit Jain]

okay...thanks

[Bear Bibeault]

shihab shahriar,
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