This Function Will Returns the value of pi.
i made a database first named ‘dbase’ within the reference of mySql(php myAdmin). Then i import all the required java packages from the java library. Here after, i made a class named ‘MySqlPIFunction’, which extends ‘HttpServlet’ Completely. Then i use service()Method that will help to getting request from the doGet()Method for output. After that, i loaded all the required drivers that are useful for database accessing. Then i declare the mandatory drivers as i use ‘connection’ variable that will use to create a link between database and java code. After that i declare ‘resultSet()that will use to get value from the columns and rows as selected table. Here after i use to declare ‘preparedStatement’ that will act as to executing selected query like executeQuery() as (Select PI()). In the last i use doGet()Method which will bring the output on the web browser.
On the web Browser i use ‘Html’ tags to print the output in tabular form on the web browser this will present output in a manner way.
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MySqlPIFunction extends HttpServlet
{
public void service(HttpServletRequest rq, HttpServletResponse rp)throws IOException, ServletException
{
rp.setContentType("text/html");
PrintWriter disp = rp.getWriter();
String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost/dbase";
String uid = "root";
String psw = "root";
Connection con=null;
PreparedStatement ps = null;
ResultSet rs;
try
{
Class.forName(driver);
con = DriverManager.getConnection(url,uid,psw);
ps=con.prepareStatement("Select PI()");
rs = ps.executeQuery();
String title = "Using PI Function";
String docType ="<!doctype html public \"-//w3c//dtd html 4.0 " + "transitional//en\">\n";
disp.println(docType + "<html>\n" + "<head><title>" + title + "</title></head>\n" +
"<body bgcolor=\"#f4efef\">\n" + "<h1 align=\"center\">" + title + "</h1>\n" + "<ul>\n" +
"<table width=\"50%\" border=\"1\" align=\"center\">\n" + "<th>Value</th>\n"+ "</body> </html>");
while(rs.next())
{
String val = rs.getString(1);
disp.println("<tr><td align=\"center\">" + val +"</td></tr>" );
}
}
catch(Exception e)
{
e.printStackTrace();
}
disp.close();
}
public void doPost(HttpServletRequest rq,HttpServletResponse rp)throws IOException,ServletException
{
doGet(rq,rp);
}
}
WEB.xml
<servlet>
<servlet-name>MySqlPIFunction</servlet-name>
<servlet-class>MySqlPIFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
<servlet-name>MySqlPIFunction</servlet-name>
<url-pattern>/MySqlPIFunction</url-pattern>
</servlet-mapping>
Dinesh Thakur holds an B.C.A, MCDBA, MCSD certifications. Dinesh authors the hugely popular