by Dinesh Thakur Category: Servlet with MySql Database

This function 'Like' (R%) will found the desired Criteria according to Condition.

In order to select rows that match a particular character pattern we use the LIKE operator. This character matching operation is called as wildcard search. The following symbols are used for matching the pattern % (percentage). This symbol represents any sequence of zero or more characters. _ (underscore) this symbol is used for any single character search. The % and _ symbols can be used in any combination with literal characters.

Now we have to import all required java packages. then we need to declared a class named 'JavaServletLikeQuery' which is been extends 'HttpServlet'. Now we need to serviceMethod() which is responsible for the getting request for desired result.then after need to load all the drivers as required procedure.Now we need to declare the variables like Connection(this variable does the role of interaction between  frontEnd and backEnd in other words it will make connection between database and actual code of java).resultset which will produce table of data from its own object.preparedStatement this variable will use to execute the Query like executeQuery().preparedStatement will execute below query (SELECT name FROM worker WHERE name LIKE 'R%').And after that the doGet() will have to use for fetching result on a web Browser.

Now on the browser to get an output in designer look we just use the 'HTML' code tags which will present the Output in Tabular form for an efficient look. 

EXAMPLE

 
JavaServletLikeQuery.java
 
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class JavaServletLikeQuery extends HttpServlet
 {
    public void service(HttpServletRequest rq, HttpServletResponse rp)throws IOException, ServletException
     {
       rp.setContentType("text/html");
       PrintWriter disp = rp.getWriter();
       String driver = "com.mysql.jdbc.Driver";
       String url = "jdbc:mysql://localhost/dbase";
       String uid = "root";
       String psw = "root";
       Connection con=null;
       PreparedStatement ps = null;
       ResultSet rs;
       try
        {
          Class.forName(driver);
          con = DriverManager.getConnection(url,uid,psw);
          ps=con.prepareStatement("SELECT name FROM worker WHERE name LIKE 'R%'");
          rs = ps.executeQuery();
                  String title = "Employee's Name Starts From 'R'";
          String docType ="<!doctype html public \"-//w3c//dtd html 4.0 " + "transitional//en\">\n";
              disp.println(docType + "<html>\n" + "<head><title>" + title + "</title></head>\n" +
          "<body bgcolor=\"#f4efef\">\n" + "<h3 align=\"center\">" + title + "</h3>\n" + "<ul>\n" +
                          "<table width=\"20%\" border=\"1\" align=\"center\">\n" + "</body> </html>");
          while(rs.next())
            {
              String nm = rs.getString("name");
                      disp.println("<tr><td align=\"center\">"+ nm +           "</td></tr>" );   
            }       
            
                }     
                  catch(Exception e) 
                              {
                                e.printStackTrace();
                              }
                                    disp.close();
                                     
    }
                       public void doPost(HttpServletRequest rq,HttpServletResponse rp)throws IOException,ServletException
                           {
                                     doGet(rq,rp);
                           }
 }

web.XML

<servlet> 

   <servlet-name>JavaServletLikeQuery</servlet-name>
   <servlet-class>JavaServletLikeQuery</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>JavaServletLikeQuery</servlet-name>
   <url-pattern>/JavaServletLikeQuery </url-pattern>
</servlet-mapping>




About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.



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