by Dinesh Thakur Category: Servlet with MySql Database

To check a value within a set IN operator is used.

We need to make a table named 'inq' into a databse named 'dbase'. the required fields must be filled with values. After that some kind of packages to be called from java library to catch up java admiration. Here we need to define a class named 'JavaServletINQuery' extends the 'HttpServlet'. this program is been responsible for desired output as required statement from user. here we use the service method()(this method is responsible for calling the doGet() method to getting the request). the variable which are mandatory to use link or present BackEnd and FrontEnd will have to be declared like Connection,ResultSet,preparedStatement all these variables does their required functions or job. like the connection variable will use to make Connection between databse and java code. the drivers are also to be load then created an object of Connection interface. after that preparedStatement will use to represent the Query for output like 'SELECT emp_id, last_name, salary, manager_id FROM inq WHERE manager_id IN (403, 417, 425)'.the resultset will be define as executeQuery() to execute the query for desired result. and in the last we used doGet() method for fetching result on a web browser.

To see the result in tabular form we use 'HTML' tags for an attract looking Output on a web browser.

Example :

JavaServletINQuery.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 JavaServletINQuery 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 emp_id, last_name, salary, manager_id FROM inq WHERE manager_id IN (403, 417, 425)");
              rs = ps.executeQuery();
                        String title = "Employee's Info With The Refrence Of Manager Id ";
              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" + "<h1 align=\"center\">" + title + "</h1>\n" + "<ul>\n" +
                         "<table width=\"50%\" border=\"1\" align=\"center\">\n" + "<th>Employee Id</th><th>Last Name</th><th>Salary</th><th>Manager Id</th>\n"+ "</body> </html>");
               while(rs.next())
                {
                     int e_id = rs.getInt("emp_id");
                               String l_name = rs.getString("last_name");
                               int sal = rs.getInt("salary");
                                         int m_id= rs.getInt("manager_id");
                     disp.println("<tr><td align=\"center\">"+ e_id +"<td align=\"center\">" + l_name +  "<td align=\"center\">" + sal + 
                      "<td align=\"center\">" + m_id + "</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>JavaServletINQuery</servlet-name>
   <servlet-class>JavaServletINQuery</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>JavaServletINQuery</servlet-name>
   <url-pattern>/JavaServletINQuery </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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