In this tutorial how to perform database connection and database operations such as insert, update, delete and select operations in servlets is shown.<\/p>\n
Code:<\/p>\n
index.html<\/p>\n
<html>
\n<head>
\n<title>DB Connection<\/title>
\n<meta charset=”UTF-8″>
\n<meta name=”viewport” content=”width=device-width, initial-scale=1.0″>
\n<\/head>
\n<body>
\n<form action=”Dbconn” method=”POST”>
\nID: <input type=”text” name=”id”><br>
\nName: <input type=”text” name=”nm”><br>
\nDepartment: <input type=”text” name=”dpt”><br>
\n<input type=”submit” value=”Insert” name=”s”>
\n<input type=”submit” value=”Update” name=”s”>
\n<input type=”submit” value=”Delete” name=”s”>
\n<input type=”submit” value=”Search” name=”s”>
\n<input type=”submit” value=”View” name=”s”>
\n<\/form>
\n<\/body>
\n<\/html><\/p>\n
Dbconn.java<\/p>\n
import java.io.IOException;
\nimport java.io.PrintWriter;
\nimport javax.servlet.ServletException;
\nimport javax.servlet.http.HttpServlet;
\nimport javax.servlet.http.HttpServletRequest;
\nimport javax.servlet.http.HttpServletResponse;
\nimport java.sql.*;
\npublic class Dbconn extends HttpServlet {
\nprotected void doPost(HttpServletRequest req, HttpServletResponse res)
\nthrows ServletException, IOException {
\nres.setContentType(“text\/html;charset=UTF-8”);
\ntry (PrintWriter out = res.getWriter()) {
\nint id=Integer.parseInt(req.getParameter(“id”));
\nString nm=req.getParameter(“nm”);
\nString dpt=req.getParameter(“dpt”);
\nString s=req.getParameter(“s”);<\/p>\n
try{
\nClass.forName(“net.ucanaccess.jdbc.UcanaccessDriver”);
\nString url=”jdbc:ucanaccess:\/\/D:\/Employee.accdb”;<\/p>\n
Connection con=DriverManager.getConnection(url);<\/p>\n
if(con!=null)
\n{
\nout.println(“Database Connected Successfully”);
\n}
\nelse
\n{
\nout.println(“Error in Connection”);
\n}
\n\/\/For insert
\nif(“Insert”.equals(s))
\n{
\n\/\/String qry=”insert into Employee(Name,Department) values ‘”+nm+”‘,'”+dpt+”‘;”;
\nString qry=”insert into Employee(Name,Department) values(?,?);”;
\nPreparedStatement ps=(PreparedStatement)con.prepareStatement(qry);
\nif(ps!=null)
\n{
\nout.println(“Statement Prepared Successfully”);
\n}
\nelse
\n{
\nout.println(“Statement not Prepared”);
\n}<\/p>\n
ps.setString(1,nm);
\nps.setString(2,dpt);<\/p>\n
int i=ps.executeUpdate();
\nif(i!=0)
\n{
\nout.println(“Record Inserted”);
\n}
\nelse
\n{
\nout.println(“Record not Inserted”);
\n}
\n}
\n\/\/For update
\nelse if(“Update”.equals(s))
\n{
\nString qry=”update Employee SET Department=? where Name=?;”;
\nPreparedStatement ps=(PreparedStatement)con.prepareStatement(qry);
\nif(ps!=null)
\n{
\nout.println(“Statement Prepared Successfully”);
\n}
\nelse
\n{
\nout.println(“Statement not Prepared”);
\n}<\/p>\n
ps.setString(2,nm);
\nps.setString(1,dpt);<\/p>\n
int i=ps.executeUpdate();
\nif(i!=0)
\n{
\nout.println(“Record Updated”);
\n}
\nelse
\n{
\nout.println(“Record does not exist”);
\n}
\n}
\n\/\/For delete
\nelse if(“Delete”.equals(s))
\n{
\nString qry=”delete from Employee where Name=?;”;
\nPreparedStatement ps=(PreparedStatement)con.prepareStatement(qry);
\nif(ps!=null)
\n{
\nout.println(“Statement Prepared Successfully”);
\n}
\nelse
\n{
\nout.println(“Statement not Prepared”);
\n}<\/p>\n
ps.setString(1,nm);<\/p>\n
int i=ps.executeUpdate();
\nif(i!=0)
\n{
\nout.println(“Record Deleted”);
\n}
\nelse
\n{
\nout.println(“Record does not exist”);
\n}
\n}
\n\/\/For Search
\nelse if(“Search”.equals(s))
\n{
\nStatement stmt=con.createStatement();
\nString qry=”select * from Employee where ID='”+id+”‘;”;
\nResultSet rs=stmt.executeQuery(qry);<\/p>\n
if(rs.next())
\n{
\nout.println(“<html><body><table border=’1′><tr><th>ID<\/th><th>Name<\/th><th>Department<\/th><\/tr>”);
\nString eid=rs.getString(“ID”);
\nString name=rs.getString(“Name”);
\nString dept=rs.getString(“Department”);<\/p>\n
out.println(“<tr><td>”+eid+”<\/td><td>”+name+”<\/td><td>”+dept+”<\/td><\/tr><\/table><\/body><\/html>”);
\n}
\nelse
\n{
\nout.println(“No records Found”);
\n}
\nrs.close();
\n}
\n\/\/For View
\nelse if(“View”.equals(s))
\n{
\nStatement stmt=con.createStatement();
\nString qry=”select * from Employee;”;
\nResultSet rs=stmt.executeQuery(qry);<\/p>\n
out.println(“<html><body><table border=’1’><tr><th>ID<\/th><th>Name<\/th><th>Department<\/th><\/tr>”);<\/p>\n
while(rs.next())
\n{<\/p>\n
String eid=rs.getString(“ID”);
\nString name=rs.getString(“Name”);
\nString dept=rs.getString(“Department”);<\/p>\n
out.println(“<tr><td>”+eid+”<\/td><td>”+name+”<\/td><td>”+dept+”<\/td><\/tr>”);
\n}
\nout.println(“<\/table><\/body><\/html>”);
\nrs.close();
\n}
\ncon.close();
\n}
\ncatch(Exception e)
\n{
\nout.println(e);
\n}
\n}
\n}
\n}<\/p>\n