In this tutorial you will learn how to use rtrim() String function of mysql with java servlet
Mysql RTRIM() Function Example Using Java Servlet
In this tutorial you will learn how to use rtrim() String function of mysql with java servlet
RTRIM() function of mysql deletes the white or unwanted spaces from the right side of a string passed as an argument.
Syntax :
rtrim('string');
Here the argument "string" is a string.
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlRtrimServlet 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 RTRIM(" + "'" + 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.
Here I am also using the LENGTH() function which displays the length of a string, this function will help here to display the length of a string with or without white spaces before and after use of RTRIM() function.
Example :
rtrim.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>RTRIM function</title> </head> <body> <form action="MysqlRtrimServlet" method="get"> <table> <tr> <td>Enter a 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>
MysqlRtrimServlet.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 MysqlRtrimServlet 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 LENGTH(" + "'" + str + "'" +")";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
String sql1= "SELECT RTRIM(" + "'" + str + "'" + ")";
while (rs.next()) {
sql = rs.getString(1);
out.println("Length of string "+"'"+str+"'"+" before call the rtrim() function =" + "\"" + sql+ "\"");
}
ps1 = con.prepareStatement(sql1);
rs1 = ps1.executeQuery();
while (rs1.next()) {
sql1 = rs1.getString(1);
out.println("<br>After calling the rtrim() function string is =" + "\"" + sql1+ "\"");
}
sql = "SELECT LENGTH(" + "'" + sql1 + "'" +")";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sql = rs.getString(1);
out.println("<br>Length of string after call the rtrim() function =" + "\"" + 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>MysqlRtrimServlet</servlet-name> <servlet-class>MysqlRtrimServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlRtrimServlet</servlet-name> <url-pattern>/MysqlRtrimServlet</url-pattern> </servlet-mapping> </web-app>
Output
When you will execute the above example you will get the output as :
1.
2.
3.
4. But when you will enter the string with white space like as :
5. You will get the output as :
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