This Function will make a computation of given expressions.
I make a table named ‘worker’ into a database named ‘dbase’ within the reference of mySql(php myAdmin).Then We have to call The Packages From java Library. Then i Make a Class Named ‘MySqlOperatorPrecedence’ Extends “HttpServlet”. After, Initializing The Class i Declare The Methods Public void Service()Method (The service method call the doGet method for a GET request from User) and In That The Objects called “Response Object” and “Request Object Which will Work According To Work. After that i Load the Driver and Make Variables Of Resultset,Connection to establish The link between database and Query that Execute The Condition after Calling. After Declaring The Prepared statement i have to put the Query (“SELECT name, salary, 12*salary+100 cal FROM worker”).After that i Use executeQuery() Method to Extract the Result On a Web Browser.
I Use ‘HTML’ code and some tags, which will show the output in tabular form on the web browser.
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 MySqlOperatorPrecedence 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 name, salary, 12*salary+100 cal FROM worker");
rs = ps.executeQuery();
String title = "Employee's Info With Using Of Operator Precedence";
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>Name</th><th>Salary</th><th>Calculation</th>\n"+ "</body> </html>");
while(rs.next())
{
String nm = rs.getString("name");
int sal = rs.getInt("salary");
int c=rs.getInt("cal");
disp.println("<tr><td align=\"center\">" + nm + "<td align=\"center\">" + sal +"<td align=\"center\">" + c +"</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>MySqlOperatorPrecedence</servlet-name>
<servlet-class>MySqlOperatorPrecedence</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
<servlet-name>MySqlOperatorPrecedence</servlet-name>
<url-pattern>/MySqlOperatorPrecedence</url-pattern>
</servlet-mapping>
Dinesh Thakur holds an B.C.A, MCDBA, MCSD certifications. Dinesh authors the hugely popular