In this tutorial you will learn how to use hex() String function of mysql with java servlet
Mysql HEX() Function Example Using Java Servlet
In this tutorial you will learn how to use hex() String function of mysql with java servlet
HEX() method of mysql returns a hexadecimal value for the given input passed as argument into its parameter. In this function single argument is passed into its parameter. This function gives the two hexadecimal digits for every one character if the argument is a string.
Syntax :
hex(numeric value or string value);
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlHexServlet 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 am passing the two different queries "SELECT HEX("+hex_value+")" and "SELECT HEX("+"'"+hex+"'"+")";; (Here 'hex_value' and 'hex' are the variables that stores the value given by the user in the 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 :
Hex.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>Hex function</title> </head> <body> <form method="get" action="MysqlHexServlet"> <table> <tr> <td>Enter an integer value</td> <td><input type="text" name="txtName"/></td> </tr> <tr> <td>Enter a string value</td> <td><input type="text" name="txtName1"/></td> </tr> <tr> <td></td> <td><input type="submit" value="CLICK"/></td> </tr> </table> </form> </body> </html>
MysqlHexServlet.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 MysqlHexServlet 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";
Connection con;
PreparedStatement ps,ps1;
ResultSet rs,rs1;
try
{
Class.forName(className);
con= DriverManager.getConnection(url, user, password);
int hex_value= Integer.parseInt(request.getParameter("txtName"));
String sql1= "SELECT HEX("+hex_value+")";
ps1= con.prepareStatement(sql1);
rs1= ps1.executeQuery();
while(rs1.next())
{
out.println("<html>");
out.println("<table>");
out.println("<tr>");
sql1=rs1.getString(1);
out.println("<td>");
out.println("Hexadecimal value for integer input "+sql1);
out.println("</td>");
out.println("</tr>");
out.println("</table>");
}
String hex= request.getParameter("txtName1");
String sql= "SELECT HEX("+"'"+hex+"'"+")";
ps= con.prepareStatement(sql);
rs= ps.executeQuery();
while(rs.next())
{
out.println("<html>");
out.println("<table>");
out.println("<tr>");
sql= rs.getString(1);
out.println("<td>");
out.println("Hexadecimal value for string input "+sql);
out.println("</td>");
out.println("</tr>");
out.println("</table>");
}
}
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>MysqlHexServlet</servlet-name> <servlet-class>MysqlHexServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlHexServlet</servlet-name> <url-pattern>/MysqlHexServlet</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 enter the value.
3. When you will click on CLICK button you will get the output as :
4. When you will give the value like this :
5. You will get the output as :
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