In this tutorial you will learn how to use trim() String function of mysql with java servlet.
Mysql TRIM() Function Example Using Java Servlet
In this tutorial you will learn how to use trim() String function of mysql with java servlet.
TRIM() function of Mysql removes either prefixes or suffixes or both from an actual string according to the argument passed as parameter. If no any argument is passed into the parameter and if the original string contains white spaces before and after the string it returns the string after removing the white spaces.
Syntax :
trim('str');
trim(BOTH / LEADING / TRAILING 'rmStr' FROM 'string');
Here you can use either one of them BOTH, LEADING, or TRAILING. BOTH is used to remove the common string at both prefix and suffix from an original string, LEADING is used to remove the string at prefix from an original string whereas TRAILING is used to remove the string at suffix.
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlTrimServlet 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 queries in my java code "SELECT TRIM(" + str + "'"+rmStr +"'" +" FROM "+"'"+orgStr+"'"+")"; and "SELECT QUOTE ( TRIM (" +"'" +orgStr + "'"+"))"; (First query works with the additional parameters and the second only works on the string you have passed as single argument and the additional function 'QUOTE' is used only for marking then into single quote.) 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 :
trim.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>TRIM() FUNCTION</title> </head> <body> <form action="MysqlTrimServlet" method="get"> <table> <tr> <td>Enter either of them BOTH/LEADING/TRAILING </td> <td><input type="text" name="text1"/></td> </tr> <tr> <td>Enter the string which is to be removed </td> <td><input type="text" name="text2"/></td> </tr> <tr> <td>Enter the original string </td> <td><input type="text" name="text3"/></td> </tr> <tr> <td></td> <td><input type="submit" value="submit"/></td> </tr> </table> </form> </body> </html>
MysqlTrimServlet.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 MysqlTrimServlet 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 rmStr = request.getParameter("text2");
String orgStr = request.getParameter("text3");
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);
if(str.equals("")&& rmStr.equals(""))
{
String sql= "SELECT QUOTE(TRIM("+"'"+orgStr+"'"+"))";
ps = con.prepareStatement(sql);
rs= ps.executeQuery();
while(rs.next())
{
sql= rs.getString(1);
out.println("String is = "+sql);
}
}
else
{
String sql = "SELECT TRIM(" + str + "'"+rmStr +"'" +" FROM "+"'"+orgStr+"'"+")";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sql= rs.getString(1);
out.println("String is = "+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>MysqlTrimServlet</servlet-name> <servlet-class>MysqlTrimServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlTrimServlet</servlet-name> <url-pattern>/MysqlTrimServlet</url-pattern> </servlet-mapping> </web-app>
Output
1. When you will execute the above example you will get the output as :
2.
3.
4. When you will enter the string like this :
5. You will get the output like this
[ 0 ] Comments