JavaWeb登录注册系统/界面（可免积分获取，邮箱验证码，数据库连接，详细注释，可作结课作业，可用于学习，可接入其他主系统）

package main.Servlet; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.util.regex.Pattern; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import main.DAO.DAO; import main.Util.EmailUtil; import main.Util.JDBCUtil; import main.Util.User; // Servlet of forgetPassword page // Class "EmailServlet" is to send verification code to user and to check the code public class EmailServlet extends HttpServlet { private String user_email; private String vCode; // Generated verification code private String vCodeReceive; // Entered verification code private PrintWriter out; // Output stream private final EmailUtil emailUtil = EmailUtil.instance; // Class "EmailServlet"'s construction method public EmailServlet() { System.out.println("Monitoring point: Email Servlet"); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException { doPost(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException { response.setContentType("text/html"); request.setCharacterEncoding("utf-8"); response.setCharacterEncoding("utf-8"); out = response.getWriter(); user_email = request.getParameter("user_email"); // Parameter "email" from fore-end vCodeReceive = request.getParameter("verification_code"); // Parameter "vcode" from fore-end String method = request.getParameter("method"); // Parameter "method" is to choose what method is needed switch (method) { case "getVCode": // when "Get Code button" is pressed try { MGetVCode(); } catch (Exception e) { throw new RuntimeException(e); } break; case "verify": // when "Sign In button" is pressed HttpSession session = request.getSession(); // Get session session.setAttribute("email", user_email); // Transferring information to session MVerify(); break; default: break; } out.flush(); out.close(); } // Method "MGetVCode" is to confirm email address and send verification code private void MGetVCode() throws Exception { DAO dao = new DAO(); User user = new User(user_email, null); JDBCUtil db = new JDBCUtil(); Connection connection = db.GetConn(); // Configure connection and other things System.out.println("Monitoring point: Sending Verification Code"); if(!IsEmail(user_email)) { // Verify format of email address out.print("-1"); // a label to make judgement of the condition of wrong format return; // Interrupt process } else { if (!dao.Exist(connection, user)) { // Verify whether this email address is registered out.print("0"); // a label to make judgement of the condition of nonexistent email address return; } } try { emailUtil.SendEmail(user_email); // Send verification code to target email address } catch (Exception e) { e.printStackTrace(); } vCode = emailUtil.getVCode(); // Get and store the verification code sending just now out.print("1"); // a label to make judgement of the condition } // Method "IsEmail" is to provide a method to confirm the format of email address private boolean IsEmail(String email) { if(email.length() == 0) { return false; } Pattern pattern = Pattern.compile("^[a-zA-Z0-9_-]+@[a-zA-Z0-9_-]+(\\.[a-zA-Z0-9_-]+)+$"); // Regular expression return pattern.matcher(email).matches(); } // Method "MVerify" is to verify whether the verification code is correct private void MVerify() { System.out.println("Monitoring point: Verify Verification Code"); if(vCode.equals(vCodeReceive)) { out.print("1"); // a label to make judgement of the condition } else { out.print("-1"); // a label to make judgement of the condition } } public void destroy() { super.destroy(); } @Override public void init() throws ServletException { super.init(); } }