In this tutorial you will learn how to use ord() String function of mysql with java servlet
Mysql ORD() Function Example Using Java Servlet
In this tutorial you will learn how to use ord() String function of mysql with java servlet
In Mysql ORD() function takes a string as an argument and returns the leftmost character's code of that string if strings are of multi-byte. This function returns the value as similar to ASCII() value of the leftmost character if characters are not not a multi byte characters. In this function numeric value of its element bytes is calculated as :
(1st byte code) + (2nd byte code * 256) + (3rd byte code * 256^2) ...
Syntax :
ord('string');
Here the argument "string", is a string of which you want code.
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlOrdServlet 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 ORD(" + "'" +str+"'"+")"; (Here 'str', is a variable 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 :
ord.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>ORD function</title> </head> <body> <form action="MysqlOrdServlet" method="get"> <table> <tr> <td>Enter String </td> <td><input type="text" name="text1"/></td> </tr> <tr> <td></td> <td><input type="submit" value="submit"/></td> </tr> </table> </form> </body> </html>
MysqlOrdServlet.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 MysqlOrdServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String str = request.getParameter("text1");
String className = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://192.168.10.13";
String user = "root";
String password = "root";
Connection con;
PreparedStatement ps, ps1;
ResultSet rs, rs1;
try {
Class.forName(className);
con = DriverManager.getConnection(url, user, password);
String sql = "SELECT ORD(" + "'" +str+"'"+")";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sql = rs.getString(1);
out.println("Code of leftmost characters = "+ sql);
}
} 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>mysqlStringFunction</display-name> <servlet> <servlet-name>MysqlOrdServlet</servlet-name> <servlet-class>MysqlOrdServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlOrdServlet</servlet-name> <url-pattern>/MysqlOrdServlet</url-pattern> </servlet-mapping> </web-app>
Output
When you will execute the above example you will get the output as :
1.
2.
3.
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