In this tutorial you will learn how to use lower() String function of mysql with java servlet
Mysql LOWER() Function Example Using Java Servlet
In this tutorial you will learn how to use lower() String function of mysql with java servlet
Mysql provides the function to change the upper case characters of string into lower case. Here we are explaining the LOWER() function, this function provides the facility that you can change the characters of string which are in upper case to lower case. Mysql also provides similar function called LCASE().
Syntax :
lower('string');
Here the argument "string" is a string of which you want to change to small letters/lowercase.
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlLowerServlet 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 LOWER(" + "'" + 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 :
lower.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>LOWER function</title> </head> <body> <form action="MysqlLowerServlet" method="get"> <table> <tr> <td>Enter String in upper case</td> <td><input type="text" name="text1"/></td> </tr> <tr> <td></td> <td><input type="submit" value="submit"/></td> </tr> </table> </form> </body> </html>
MysqlLowerServlet.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 MysqlLowerServlet 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;
ResultSet rs;
try {
Class.forName(className);
con = DriverManager.getConnection(url, user, password);
String sql = "SELECT LOWER(" + "'" + str + "'"+")";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sql = rs.getString(1);
out.println("characters in lower case =" + "\"" + 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>MysqlLowerServlet</servlet-name> <servlet-class>MysqlLowerServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlLowerServlet</servlet-name> <url-pattern>/MysqlLowerServlet</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 submit button you will get the output as :
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