In this tutorial you will learn how to use right() function of mysql with java servlet.
Mysql RIGHT() Function Example Using Java Servlet
In this tutorial you will learn how to use right() function of mysql with java servlet.
RIGHT() function of mysql takes two argument first is taken as a string and the second is taken as a number. Here number specifies that how many characters you want from right side of a specified string. This function returns the string from right side of a specified string by discarding the left characters of full length string except the required number of characters from right side. For example 'devmanuals' is a string of full length 10, and I required only 7 characters string from right side this function will discarded the left 3 characters i.e 'dev' and will return only 7 characters string i.e. 'manuals'.
Syntax :
right('str', num);
Here "str" is an actual string that is taken as first argument, and "num" is numeric value that is taken as second argument.
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlRightServlet 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 RIGHT(" + "'" +str+"'"+","+str1+")"; (Here 'str', 'num' 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 :
right.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>RIGHT function</title> </head> <body> <form action="MysqlRightServlet" method="get"> <table> <tr> <td>Enter a String </td> <td><input type="text" name="text1"/></td> </tr> <tr> <td>Enter a number </td> <td><input type="text" name="text2"/></td> </tr> <tr> <td></td> <td><input type="submit" value="submit"/></td> </tr> </table> </form> </body> </html>
MysqlRightServlet.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 MysqlRightServlet 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");
int str1 = Integer.parseInt(request.getParameter("text2"));
String className = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://192.168.10.13";
String user = "root";
String password = "root";
Connection con;
PreparedStatement ps;
ResultSet rs;
try {
Class.forName(className);
con = DriverManager.getConnection(url, user, password);
String sql = "SELECT RIGHT(" + "'" +str+"'"+","+str1+")";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sql = rs.getString(1);
out.println("String after extracting from right side = "+ 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>MysqlRightServlet</servlet-name> <servlet-class>MysqlRightServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlRightServlet</servlet-name> <url-pattern>/MysqlRightServlet</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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