📄 dbresourcefromcontainerservlet.java

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💻 JAVA
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package com.nc21.exam.test;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

import com.nc21.exam.util.Config;

public class DBResourceFromContainerServlet extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public DBResourceFromContainerServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 * 
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doPost(request, response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 * 
	 * This method is called when a form has its tag value method equals to
	 * post.
	 * 
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		try {
			Context initContext = new InitialContext();
			Context envContext = (Context) initContext.lookup(Config.getValue("context_jndi"));
			DataSource ds = (DataSource) envContext.lookup(Config.getValue("sqlserver_jndi"));
			Connection conn = ds.getConnection();
			String testSql = "select * from orders";
			PreparedStatement ps = conn.prepareStatement(testSql);
			ResultSet rs = ps.executeQuery();
			ResultSetMetaData rsmd = rs.getMetaData();
			while (rs.next()) {
				for (int i = 1; i < rsmd.getColumnCount() + 1; i++) {
					System.out.print(rs.getString(i) + "  ");
				}
				System.out.println();
			}
			rs.close();
			ps.close();
			conn.close();
		} catch (NamingException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		out
				.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
		out.println("<HTML>");
		out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
		out.println("  <BODY>");
		out.print("    This is ");
		out.print(this.getClass());
		out.println(", using the POST method");
		out.println("  </BODY>");
		out.println("</HTML>");
		out.flush();
		out.close();
	}

	/**
	 * Initialization of the servlet. <br>
	 * 
	 * @throws ServletException
	 *             if an error occure
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}
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