Servlet_Akun.java

package control;

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 model.Akun;
import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

@WebServlet(name = "Servlet_Akun", urlPatterns = {"/Servlet_Akun"})
public class Servlet_Akun extends HttpServlet {
    protected void procesRequest(HttpServletRequest request,HttpServletResponse response)
        throws ServletException, IOException,SQLException, ClassNotFoundException {
        response.setContentType("text/html;charset=UTF-8");

        Akun akun = new Akun();

        String URL = "jdbc:mysql://localhost:3306/SIA"; //PAKAI PORT MYSQL BUKAN GLASSFISH
        String USERNAME = "root";
        String PASSWORD = "";

        Connection koneksi = null;
        PreparedStatement pstmt = null;
        int result = 0;


        try (PrintWriter out = response.getWriter()) {
        Class.forName("com.mysql.jdbc.Driver");
        koneksi = DriverManager.getConnection(URL, USERNAME, PASSWORD);

        String aksi = request.getParameter("aksi");
        if (aksi != null) {
            akun.setKode_akun(request.getParameter("kode"));
            akun.setNama_akun(request.getParameter("nama"));
            akun.setJenis_akun(request.getParameter("jenis"));
            akun.setSaldo_normal(request.getParameter("saldo"));

            switch (aksi) {
            case "Insert":
            pstmt = koneksi.prepareStatement("INSERT INTO master_akun VALUES(?, ?, ?, ?)"); //QUERY YANG SALAH
            pstmt.setString(1, akun.getKode_akun());
            pstmt.setString(2, akun.getNama_akun());
            pstmt.setString(3, akun.getJenis_akun());
            pstmt.setString(4, akun.getSaldo_normal());

            result = pstmt.executeUpdate();
            if(result > 0) {
                out.println("<script>"
                + "alert('Data telah ditambahkan');"
                + "document.location = 'AddAkun.jsp';"
                + "</script>");
            }
            break;
            default:
            break;
            }
        }
    }
   }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        try {
            procesRequest(request, response);
        } catch (SQLException ex) {
            Logger.getLogger(Servlet_Akun.class.getName());
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(Servlet_Akun.class.getName());
        }
    }
}