Jsp parses user login and registration instances (with source code) based on XML, jspxml
Simple xml-based database login and Registration
Topic introduction:
1. xml reading and storage, mainly using dom4j Technology, (The network file storage PATH uses classLoader)
File Reading and storage, write a factory class
Public class DocumentFactory {private static Document dom = null; // you need to share a dom, so you need to set it to static private static String name = "user. xml "; private static String filename; // write a static block to read the dom tree. static {// dom4j technology SAXReader read = new SAXReader (); filename = DocumentFactory. class. getClassLoader (). getResource (name ). getPath (); // use the class loader to read files. try {dom = read. read (filename);} catch (incluentexception e) {<span style = "font-f Amily: Arial, Helvetica, sans-serif; "> e. printStackTrace () ;}</span> // mainly obtains and stores two functions (in single-sample mode) (One dom must be shared) public static Document getDocument () {// get the dom tree return dom in xml;} // after registration, Save public static void Save () {XMLWriter wr; try {wr = new XMLWriter (new FileOutputStream (filename);} catch (Exception e1) {throw new RuntimeException ("An error occurred while reading the file");} try {wr. write (dom);} catch (IOException e) {thro W new RuntimeException ("failed to write the file" + e. getMessage ();} finally {try {if (wr! = Null) {wr. close () ;}} catch (IOException e) {throw new RuntimeException ("failed to close the stream" + e. getMessage ());}}}}
2. Front-end technology: It is basically the construction of the interface and the data is uploaded to the background for processing. And some required options.
Code for two pages:
// Log on
<Body> <form action = 'login' method = "post"> Username: <input type = "text" name = "name"/> <br/> password: <input type = "text" name = "pwd"/> <br/> Verification Code: <input type = "text" name = "checkCode"> <a href = "javascript: flush () "> cannot see </a> // rewrite a js file to refresh it <br/> <input type =" submit "value =" Logon "/> <input type =" reset" value = "reset"/> <a href = 'jsps/Reg. jsp '> Registration </a> </form>
// Log on to the background
Public class Login extends HttpServlet {public void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost (request, response);} public void doPost (HttpServletRequest request, response) throws ServletException, IOException {request. setCharacterEncoding ("UTF-8"); // set the UTF-8 encoding format to receive response. setContentType ("text/html; charset = U TF-8 "); // <span style =" color: # ff0000; "> set the page display mode, which must be set before getting the output stream, or the setting is useless, garbled characters will still appear </span> PrintWriter out = response. getWriter (); out. println ("<! Doctype html public \ "-// W3C // dtd html 4.01 Transitional // EN \"> "); out. println ("<HTML>"); out. println ("<HEAD> <TITLE> A Servlet </TITLE>"); out. println ("<meta http-equiv = 'content-type' content = 'text/html; charset = UTF-8 '> </HEAD>"); out. println ("<BODY>"); String name = request. getParameter ("name"); String pwd = request. getParameter ("pwd"); String check = request. getParameter ("checkCode"); // obtain the value Im entered by the Verification code from the interface GDemo id = new ImgDemo (); String str = id. getStr (); if (! Check. equals (str) {out. println ("Logon Failed, incorrect verification code !! "); // If the verification code does not match, return directly to the logon interface out. print ("<a href = 'index. jsp '> return to logon </a> "); return;} // System. out. println ("11" + check); // System. out. println ("22" + str); // obtain all objects before logon. Document dom = DocumentFactory. getDocument (); boolean flag = false; Element root = dom. getRootElement (); Iterator <Element> it = root. elementIterator (); while (it. hasNext () {Element ele = it. next (); String nameC = ele. attributeValue ("name"); String pwdC = el E. attributeValue ("pwd"); if (name. trim (). equals (nameC) & pwdC. equals (pwdC) {flag = true; break ;}} if (flag) {out. print ("<font color = 'red' size = '8px '> congratulations! login successful! </Font> "); out. println ("<a href = 'index. jsp '> return to logon </a> ");} else {out. print ("the user name and password do not match. Login Failed... "); Out. println ("<a href = 'index. jsp '> return to logon </a> ");} out. println ("</BODY>"); out. println ("</HTML>"); out. flush (); out. close ();}}
// Register
<Body> <form action = 'reg 'method = "post"> User name: <input type = "text" name = "name" onblur = "check () "id =" name "/> <span id =" spanid "> </span> <br/> password: <input type = "text" name = "pwd" id = "pwd" onblur = "check1 () "/> <span id =" spanid1 "> </span> <br/> confirm the password: <input type = "text" name = "pwd2" id = "pwd2" onblur = "check2 () "/> <span id =" spanid2 "> </span> <br/> <input type =" submit "value =" register "/> <input type =" reset" value = "reset"/> </form> </body>
// Registration background processing
Public void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response. setContentType ("text/html; charset = UTF-8"); // <span style = "color: # ff0000;"> before obtaining Printwrite, the setting is invalid </span> PrintWriter out = response. getWriter (); out. println ("<! Doctype html public \ "-// W3C // dtd html 4.01 Transitional // EN \"> "); out. println ("<HTML>"); out. println ("<HEAD> <TITLE> A Servlet </TITLE> </HEAD>"); out. println ("<BODY>"); boolean flag = false; request. setCharacterEncoding ("UTF-8"); String name = request. getParameter ("name"); String pwd = request. getParameter ("pwd"); Document dom = DocumentFactory. getDocument (); Element root = dom. getRootElement (); Iterator <El Ement> it = root. elementIterator (); while (it. hasNext () {Element ele = it. next (); String nameR = ele. attributeValue ("name"); // The value passed here may be null. so we have to prevent it at the front-end. Of course, here we also need to consider String pwdR = ele. attributeValue ("pwd"); if (name. equals (nameR) & pwd. equals (pwdR) {flag = true; break ;}} if (flag) {out. print ("this user has been registered !! "); Out. print ("<a href = 'jsps/Reg. jsp '> return registration </a> ");} else {Element ele = root. addElement ("user"); ele. addAttribute ("name", name); ele. addAttribute ("pwd", pwd); DocumentFactory. save (); out. print ("registration successful !! "); Out. print ("<a href = 'index. jsp '> return to logon </a> ");} out. println ("</BODY>"); out. println ("</HTML> ");}
3. Verification code technology: the same image is obtained from the background and matched upon login
:
1. Verify the verification code first.
2. Password matching
3. User Registration
4. The password is correct.
5. view the user. xml file
Source code for the entire login and registration: jsp parses user login and registration instances Based on XML
The above is all the content of this article, hoping to help you learn.
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