In this tutorial you will learn about how to use pow() function in math function of mysql using servlet.
MySql POW() Function Example Using Java Servlet
In this tutorial you will learn about how to use pow() function in math function of mysql using servlet.
POW() function in MySql gives the value after calculating the number raised to the power of the another number that is calculating xy.
Syntax :
pow();
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlPowServlet which extends the HttpServlet class. In the body of class I overridden the method doGet() and created an objects of HttpServletRequest and HttpServletResponse into its parameter. Inside the doGet() method first I set the mime type that in which format the browser will show the output. In the next line I used the getWriter() method of ServletResponse interface with the object of HttpServletResponse. HttpServletResponse interface extends this method from the ServletResponse. In Next step I am taking inputs using the getParameter() method of ServletRequest with the object of HttpServletRequest. In continue we have to establish a connection between java code and database system. So, since I am using Mysql in the example given below therefore, I am loading the driver of mysql and make a connection by using the getConnection() method of DriverManager class. It returns a Connection. Further I passed the query "SELECT Pow("+bs+","+pw+")"; (Here 'bs' and 'pw' are variables that stores the value given by the user in their respective textfields.) into the parameter of prepareStatement() method of Connection interface which gives an object of PreparedStatement interface. In the next line I used the executeQuery() method of PreparedStatement interface which returns a ResultSet object that holds the result of query. At last I have extracted the result from the ResultSet object.
Example :
pow.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>POW() Function</title> </head> <body> <form method="get" action="MysqlPowServlet"> <table> <tr> <td>Enter base value</td><td><input type="text" name="text1"/></td> </tr> <tr> <td>Enter exponent value</td><td><input type="text" name="text2"/></td> </tr> <tr> <td align="center"> <input type="submit" value ="ok"/></td> </tr> </table> </form> </body> </html>
MysqlPowServlet.java
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.SQLException;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MysqlPowServlet extends HttpServlet
{
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String className = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://192.168.10.13";
String user = "root";
String password = "root";
double bs = Double.parseDouble(request.getParameter("text1"));
double pw = Double.parseDouble(request.getParameter("text2"));
Connection con;
PreparedStatement ps;
ResultSet rs;
try
{
Class.forName(className);
con = DriverManager.getConnection(url, user, password);
String sql = "SELECT Pow("+bs+","+pw+")";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
while(rs.next())
{
double pow = Double.parseDouble(rs.getString(1));
out.println("<html>");
out.println(bs+"<sup>"+pw+"</sup> = "+pow);
out.println("</html>");
}
}
catch(SQLException sx)
{
out.println(sx);
}
catch(ClassNotFoundException cx)
{
out.println(cx);
}
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>mysqlMathematicalFunction</display-name> <servlet> <servlet-name>MysqlPowServlet</servlet-name> <servlet-class>MysqlPowServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlPowServlet</servlet-name> <url-pattern>/MysqlPowServlet</url-pattern> </servlet-mapping> </web-app>
Output
When you will execute the above example you will get the output as :
1.
2. When you will entered the value like as :
3. When you will click on "ok" button you will get the output as :
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