Database WebApp with Wildfly and mySQL in Docker container

  Docker, mySQL, Servlet, Wildfly

Example 1: A servlet

Contents

Now it is time to make use of the container. You will have to create a dynamic web app (Eclipse Project) with only a single servlet. On request the servlet creates a database connection and shows a list of actors from the sakila database.

package de.neuromechanics;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.annotation.Resource;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

/**
 * Servlet implementation class DatasourceServlet
 */
@WebServlet("/myds")

public class DatasourceServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	
	@Resource(name="sakilaDS")
	private DataSource ds;

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		final PrintWriter writer = response.getWriter();

		response.setContentType("text/html; charset=UTF-8");
		writer.println("<!DOCTYPE html>");
		writer.println("<html>");
		writer.println("<body>");
		writer.println("<table border='1'>");
		writer.println("<tr>");
		writer.println("<th>Lastname</th>");
		writer.println("<th>ID</th>");
		writer.println("</tr>");

		Connection con;
		try {
			con = ds.getConnection();
			Statement stmt = con.createStatement();
			ResultSet rs = stmt.executeQuery("SELECT last_name, actor_id FROM actor");
			while (rs.next()) {
				String name = rs.getString("last_name");
				String id = rs.getString("actor_id");
				writer.println("<tr>");
				writer.println("<td>" + name + "</td>");
				writer.println("<td>" + id + "</td>");
				writer.println("</tr>");
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		writer.println("</table></body></html>");
	}
}

For this to work we need a resource reference to the sakila datasource. For Wildfly/JBoss this is done via the jboss-web.xml in the WEB-INF folder of the application.

<?xml version="1.0" encoding="UTF-8"?>
<jboss-web>
    <resource-ref>
        <res-ref-name>sakilaDS</res-ref-name>
        <jndi-name>java:/jdbc/datasources/sakilaDS</jndi-name>
    </resource-ref>
</jboss-web>

The final step will be to create a deployable web archive (.war) file and copy it into the folder which we share with the wildfly container. To do so, we must “Export” our Eclipse project to a WAR file. In Eclipse project explorer right-click on the project’s top entry and select “Export”. After you selected “WAR file” you’re asked for a destination into which to put the war-file. Here we specify the exact same path we chose in the -v parameter when we created the wildfly container (-v C:\[CUSTOM_PATH]\JBoss_deployments ….. Hopefully you didn’t forget to replace [CUSTOM_PATH] with the path you’ve chosen at that time).

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