how can be implement single threaded model in servlets.

Question

Hi we want to know that how to implement single threaded model in servlets.

Satyapriya Nayak · Answer

Hi Abhishek A servlet class is instantiated the first time it is invoked. The same instance will be used over several client requests. This is multi-threaded model multiple clients that access the same instance. In multi-threaded model one client can change the internal state of the servlet this will affect the other clients so to protect servlet member's variables to be modified by different clients Single threaded model is used. To implement this model SingleThreadModel interface is implemented in servlets. This interface is used to indicate that only a single thread will execute the service( ) method of a servlet at a given time. It defines no constants and declares no methods.If a servlet implements this interface the server has two options. First it can create several instances of the servlet. When a client request arrives it is sent to an available instance of the servlet. Second it can synchronize access to the servlet. import java.io.*; import java.sql.*; import java.util.*; import javax.servlet.*; import javax.servlet.http.*; public class SingleThread extends HttpServlet implements SingleThreadModel { private int numberOfRows=0; Connection con=null; public void init() { try { Class.forName(sun.jdbc.odbc.JdbcOdbcDriver); System.out.println(Driver registered with the driver manager class); Connection con = DriverManager.getConnection(jdbc:odbc:students); System.out.println(connected); } catch(Exception e) { System.out.println(e); } } public void doGet(HttpServletRequest r1 HttpServletResponse r2) throws IOException { ResultSet rs = null; PreparedStatement pStmt = null; int startingRows = numberOfRows; try { String students= null; pStmt = con.prepareStatement (select * from stud. students); rs = pStmt.executeQuery(); } catch (Exception es) { System.out.println(es); } } } Thanks