loginservlet.java

本光盘包含了本书各章中出现的所有程序的源代码。 1. 如果是Java程序

package com.web.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

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

/**
 * Servlet implementation class for Servlet: LoginServlet
 * 
 */
public class LoginServlet extends javax.servlet.http.HttpServlet implements
		javax.servlet.Servlet {
	static final long serialVersionUID = 1L;

	/*
	 * (non-Java-doc)
	 * 
	 * @see javax.servlet.http.HttpServlet#HttpServlet()
	 */
	public LoginServlet() {
		super();
	}

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

	/**
	 * 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 {
		String username = request.getParameter("username");
		String password = request.getParameter("password");

		RequestDispatcher dis = null;
		try {
			Class.forName("com.mysql.jdbc.Driver");
			Connection con = DriverManager.getConnection(
					"jdbc:mysql://localhost:3306/hellodb", "root", "123456");
			PreparedStatement sta = con
					.prepareStatement("select * from users where username = ? and password = ?");
			sta.setString(1, username);
			sta.setString(2, password);

			ResultSet rs = sta.executeQuery();

			if (rs.next()) {
				dis = request.getRequestDispatcher("success.jsp");
			} else {
				dis = request.getRequestDispatcher("failed.jsp");
			}

			rs.close();
			sta.close();
			con.close();
		} catch (Exception e) {
			e.printStackTrace();
		}

		if (dis != null)
			dis.forward(request, response);
	}

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