In order to keep the main knowledge point clear, this module does not use Ajax technology, so it does not implement the registration time mark down function to verify whether the user name is occupied. Besides, the JS verification username and password of the client are omitted for compliance with the required functions. There are only two registration fields, namely the nickname and password. The nickname must be unique and the primary key is automatically increased. The database uses MySQL.
First, let's look at the file directory structure of the module:
The following is the source code of the three servlets:
Public class checkcodeservlet extends httpservlet {public void Service (httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {response. setcontenttype ("image/JPEG"); bufferedimage image = new bufferedimage (60, 20, bufferedimage. type_int_rgb); graphics G = image. getgraphics (); // system. out. println (G. getclass (); random r = new random (); G. setcolor (new color (R. nextint (1, 255), R. nextint (1, 255), R. nextint (255); G. fillrect (0, 0, 60, 20); G. setcolor (new color (0, 0); string number = string. valueof (R. nextint (99999); httpsession session = request. getsession (); Session. setattribute ("Number", number); G. drawstring (number, 5, 15); G. setcolor (new color (R. nextint (1, 255), R. nextint (1, 255), R. nextint (255); G. drawline (R. nextint (10), R. nextint (10), 40 + R. nextint (20), R. nextint (20); outputstream out = response. getoutputstream (); // compress the image into imageencoder encoder = required codec. createjpegencoder (out); // system. out. println (encoder. getclass (); encoder. encode (image );}}
Public class registerservlet extends httpservlet {public void Service (httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {request. setcharacterencoding ("UTF-8"); string nickname = request. getparameter ("nickname"); string Password = request. getparameter ("password"); string checkcode = request. getparameter ("checkcode"); httpsession session = request. getsession (); string n Umber = (string) Session. getattribute ("Number"); If (! Number. equals (checkcode) {request. setattribute ("checkcode_err", "Incorrect verification code"); Request. getrequestdispatcher ("register. JSP "). forward (request, response); return;} userdao Dao = new userdao (); try {user = Dao. findbynickname (nickname); If (user! = NULL) {request. setattribute ("register_err", "username occupied"); Request. getrequestdispatcher ("register. JSP "). forward (request, response);} else {user user2 = new user (nickname, password); Dao. save (user2); response. sendredirect ("login. JSP ") ;}} catch (exception e) {e. printstacktrace (); throw new servletexception (e );}}}
Public class loginservlet extends httpservlet {public void Service (httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {request. setcharacterencoding ("UTF-8"); string nickname = request. getparameter ("nickname"); string Password = request. getparameter ("password"); userdao Dao = new userdao (); try {user = Dao. findbynickname (nickname); If (user! = NULL & user. getPassword (). equals (password) {httpsession session = request. getsession (); Session. setattribute ("user", user); response. sendredirect ("welcome. JSP ");} else {request. setattribute ("login_err", "incorrect user name or password"); Request. getrequestdispatcher ("login. JSP "). forward (request, response) ;}} catch (exception e) {e. printstacktrace (); throw new servletexception (e );}}}
By the way, the source code of the four JSP files is attached:
Register. jsp:
<% @ Page contenttype = "text/html; charset = UTF-8 "pageencoding =" UTF-8 "%> <HTML>Login. jsp:
<% @ Page contenttype = "text/html; charset = UTF-8 "pageencoding =" UTF-8 "%> <HTML>Welcome. jsp:
<%@ page contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%><%@ include file="sessionValidate.jsp" %>Sessionvalidate. jsp:
<%Object obj=session.getAttribute("user");if(obj==null){ response.sendRedirect("login.jsp");}%>The package file of the entire module has been uploaded to my resources and can be downloaded for free. The SQL script is too simple and is not provided. IDE is myeclipse. Although simple, cainiao can learn.
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