Mysql PERIOD_DIFF() Function Using Java Servlet

In this tutorial you will learn how to use mysql period_diff() in java servlet.

Mysql PERIOD_DIFF() Function Using Java Servlet

In this tutorial you will learn how to use mysql period_diff() in java servlet.

PERIOD_DIFF() function of mysql differentiates the two periods. To differentiate, the format of periods should be similar i.e. format should be in either yyyymm or yymm.

Syntax :

period_diff(period1, period2);

Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlPeriodDiffServlet 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 continue we have to make 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 am passing the query "SELECT PERIOD_DIFF(201209, 201108)" (This query will return the output of difference between periods as 13 ) 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 :

MysqlPeriodDiffServlet.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 MysqlPeriodDiffServlet extends HttpServlet
{
 public void doGet(HttpServletRequest req, HttpServletResponse res)
  throws IOException, ServletException
  {
   res.setContentType("text/html");
   PrintWriter pw = res.getWriter();
   String className = "com.mysql.jdbc.Driver";
   String url = "jdbc:mysql://192.168.10.13/data";
   String user = "root";
   String password = "root";
   String sql = "SELECT PERIOD_DIFF(201209, 201108)";
   Connection con;
   PreparedStatement ps;
   ResultSet rs;
   
   try
   {
	 Class.forName(className);
	 con = DriverManager.getConnection(url, user, password);
	 ps = con.prepareStatement(sql);
	 rs = ps.executeQuery();
	 
	 pw.println("<table>");
	 pw.println("<tr>");
	 pw.println("<td><b>PERIOD_DIFF(201209, 201108)</b></td>");
	 pw.println("</tr>");
	 
	 while(rs.next())
	 {
	  String period = rs.getString(1);
	  pw.println("<tr>");
	  pw.println("<td>"+period+"</td>");
	  pw.println("</tr>");
	 }
	 pw.println("</table>");
   }
   catch(SQLException sx)
   {
	pw.println(sx);
   }
   catch(ClassNotFoundException cx)
   {
	pw.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>mysqlDate</display-name>

<servlet>
<servlet-name>MysqlPeriodDiffServlet</servlet-name>
<servlet-class>MysqlPeriodDiffServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>MysqlPeriodDiffServlet</servlet-name>
<url-pattern>/MysqlPeriodDiffServlet</url-pattern>
</servlet-mapping>

</web-app>

Output :

When you will execute the above example you will get the output as :

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