DatabaseServlet.java Source code

Introduction

Here is the source code for DatabaseServlet.java
Source

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DatabaseServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, java.io.IOException {

        String sql = "select * from atable";
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        ResultSetMetaData rsm = null;

        response.setContentType("text/html");
        java.io.PrintWriter out = response.getWriter();
        out.println("<html><head><title>Typical Database Access</title></head><body>");
        out.println("<h2>Database info</h2>");
        out.println("<table border='1'><tr>");

        try {

            //load the database driver
            Class.forName("oracle.jdbc.driver.OracleDriver");

            //The JDBC URL for this Oracle database
            String url = "jdbc:oracle:thin:@142.3.169.178:1521:ORCL";

            //Create the java.sql.Connection to the database
            conn = DriverManager.getConnection(url, "usr", "pass");

            //Create a statement for executing some SQL
            stmt = conn.createStatement();

            rs = stmt.executeQuery(sql);

            rsm = rs.getMetaData();

            int colCount = rsm.getColumnCount();

            //print column names
            for (int i = 1; i <= colCount; ++i) {

                out.println("<th>" + rsm.getColumnName(i) + "</th>");
            }

            out.println("</tr>");

            while (rs.next()) {

                out.println("<tr>");

                for (int i = 1; i <= colCount; ++i)
                    out.println("<td>" + rs.getString(i) + "</td>");

                out.println("</tr>");

            }

        } catch (Exception e) {

            throw new ServletException(e.getMessage());

        } finally {

            try {

                stmt.close();
                conn.close();

            } catch (SQLException sqle) {
            }

        }

        out.println("</table><br><br>");

        out.println("</body>");
        out.println("</html>");

        out.close();

    } //doGet

}