Connect Servlet to the Database

Connect Servlet to the Database with Example

 Files Required

  ·         index.html

  ·         ServletDatabaseConnect.java

  ·         web.xml

  ·         ojdbc14.jar

index.html      

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<form action="show" method="post">   <font face="verdana" size="2">      Enter Table Name :<input type="text" name="table">     <input type="submit" value="Display">   </font> </form>

ServletDatabaseConnect.java

package java4s;

import java.io.IOException;

import java.io.PrintWriter;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.Statement;

 import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 public class ServletDatabaseConnect extends HttpServlet  

{

    protected void doPost(HttpServletRequest req,HttpServletResponse res)throws ServletException,IOException

    {

        PrintWriter pw=res.getWriter();

        res.setContentType("text/html");        

        String tb=req.getParameter("table");    

        try

        {

             Class.forName("oracle.jdbc.driver.OracleDriver");

             Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE","system","admin");

             Statement st=con.createStatement();

             System.out.println("connection established successfully...!!");    

             ResultSet rs=st.executeQuery("Select * from "+tb);

             pw.println("<table border=1>");

                 while(rs.next())

                 {

                     pw.println("<tr><td>"+rs.getInt(1)+"</td><td>"+rs.getString(2)+"</td>"+

                                      "<td>"+rs.getString(3)+"</td></tr>");

                 }

             pw.println("</table>");

             pw.close();

        }

        catch (Exception e){

            e.printStackTrace();

        }

     }

}

web.xml

<web-app>

     <servlet>

        <servlet-name>ServletDBConnect</servlet-name>

        <servlet-class>java4s.ServletDatabaseConnect</servlet-class>    

     </servlet>

     <servlet-mapping>

            <servlet-name>ServletDBConnect</servlet-name>

            <url-pattern>/show</url-pattern>

    </servlet-mapping>

 </web-app>