In this tutorial you will learn how to use regexp operator of mysql with java servlet
Mysql REGEXP Operator Example Using Java Servlet
In this tutorial you will learn how to use regexp operator of mysql with java servlet
REGEXP is an operator that is used in MySql to match an expression according to a specified pattern these, pattern are given as argument. If the specified pattern is matched into the specified string it returns '1' else returns '0' and if the string or pattern is given to null it also returns null.
Syntax :
regexp 'pattern';
Here "pattern" is a pattern that is to be matched in a string. In the example given below I used the '$'. The '$' matches the right after the last character in the string.
Now, since I have to use this function in java servlet program, therefore I have created a java servlet class named MysqlRegExpServlet 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 LCASE(" + "'" +str+"'"+")"+ "REGEXP"+ "'"+str1+"'"; (Here 'str', 'str1' are variables that stores the value given by the user in their respective textfields and REGEXP is an operator.) 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 :
regexp.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>REGEXP operator</title> </head> <body> <form action="MysqlRegExpServlet" method="get"> <table> <tr> <td>Enter a String </td> <td><input type="text" name="text1"/></td> </tr> <tr> <td>Enter a pattern to be match </td> <td><input type="text" name="text2"/></td> </tr> <tr> <td></td> <td><input type="submit" value="submit"/></td> </tr> </table> </form> </body> </html>
MysqlRegExpServlet.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 MysqlRegExpServlet 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 str1 = 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 LCASE(" + "'" +str+"'"+")"+ "REGEXP"+ "'"+str1+"'";
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sql = rs.getString(1);
if(sql.equals("1"))
out.println("String is matched");
else
out.println("String is not matched");
}
} 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>MysqlRegExpServlet</servlet-name> <servlet-class>MysqlRegExpServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>MysqlRegExpServlet</servlet-name> <url-pattern>/MysqlRegExpServlet</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 output like :
5. You will get the output as :
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