Here we will implement a login Effect Using ajax asynchronous implementation in the future. Let's just look at the Code:
Logon page:
<! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <HTML xmlns = "http://www.w3.org/1999/xhtml">Jquery code for Ajax implementation:
Function verify () {// alert (""); // method 1 to solve the Chinese Garbled text problem. encodeuri is performed on the data sent from the page, the server uses new string (old. getbytes ("iso8859-1"), "UTF-8") // var url = "ajaxserver? Name = "+ encodeuri ($ (" # username "). val (); // encodeuri handles Chinese Garbled text; // method 2 to solve Chinese Garbled text. the data sent by the page is processed by encodeuri twice, and the server uses urldecoder. decode (old, "UTF-8"); var input = $ ("input [name = 'type']"); // The value selected by the single button cannot be obtained, so we can only get all the values first, and judge for (I = 0; I <input. length; I ++) {If (input [I]. checked) {// alert (input [I]. value); var url = "users? Name = "+ encodeuri ($ (" # username "). val () + "& Password =" + encodeuri ($ ("# userpassword "). val () + "& type =" + encodeuri (input [I]. value); // encodeuri for handling Chinese garbled characters} url = converturl (URL); // obtain the function return value 'login? Uname = '+ uname +' & psw = '+ psw $. get (URL, null, function (data) {$ ("# result1" ).html (data); // simplified version}); // alert (URL );} // Add a timestamp to the URL and cheat the browser. The function converturl (URL) {// obtain the timestamp var timstamp = (new date ()). valueof (); // splice the timestamp information to the URL if (URL. indexof ("? ")> = 0) {// use indexof to determine whether the URL address has a question mark (url = URL +" & t = "+ timstamp;} else {url = URL + "? T = "+ timstamp;} return URL ;}The processing code of the backend servlet:
Package COM. xidian. BBS. servlet; import Java. io. ioexception; import Java. io. printwriter; import java.net. urldecoder; import Java. SQL. connection; import Java. SQL. resultset; import Java. SQL. statement; import javax. servlet. servletexception; import javax. servlet. HTTP. httpservlet; import javax. servlet. HTTP. httpservletrequest; import javax. servlet. HTTP. httpservletresponse; import javax. servlet. HTTP. httpsession; impor T COM. xidian. BBS. util. dbaccess; @ suppresswarnings ("serial") public class users extends httpservlet {public void doget (httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {response. setcontenttype ("text/html; charset = UTF-8"); Request. setcharacterencoding ("UTF-8"); response. setcharacterencoding ("UTF-8"); printwriter out = response. getwriter (); // 1. take the parameter S passed in JS Tring name1 = request. getparameter ("name"); string password1 = request. getparameter ("password"); string type1 = request. getparameter ("type"); // string name = new string (old. getbytes ("iso8859-1"), "UTF-8"); // process Chinese garbled 1, need to match the encodeuri in the front-end JS file with string name2 = urldecoder. decode (name1, "UTF-8"); // process Chinese Garbled text 2 string password2 = urldecoder. decode (password1, "UTF-8"); string type2 = urldecoder. decode (type1, "UTF-8"); If (Na Me2 = NULL | name2.length () = 0) {out. println ("the user name cannot be blank !! "); Return; // do not execute the following code} else if (password2 = NULL | password2.length () = 0) {out. println ("the password cannot be blank !! "); Return;} // 3. check statement SQL = NULL; resultset rs = NULL; try {connection con = dbaccess. getconnection (); SQL = con. createstatement (resultset. type_scroll_sensitive, resultset. concur_updatable); If (type2.equals ("consortium member") {httpsession session = request. getsession (); Session. setattribute ("bs_type", "consortium member"); RS = SQL .exe cutequery ("select * From yh_yhxx"); While (RS. next () {string yhxx_id = Rs. gets Tring ("yhxx_id"); string yhxx_pwd = Rs. getstring ("yhxx_psw"); system. out. println (yhxx_id + "" + yhxx_pwd); // 2. check whether the parameter is correct. // 3. verify if (name2.equals (yhxx_id) & password2.equals (yhxx_pwd) {// 4. unlike traditional applications, this step returns data of interest to the page end. Instead of returning a new page to the page, the writing method has not changed, and the session has changed in essence. setattribute ("username", name2); out. println ("<script language = 'javascript '> window. location. href = 'index. JSP '; </SCRIPT> "); out. flush (); out. close () ;}} else {httpsession session = request. getsession (); Session. setattribute ("bs_type", "Forum member"); RS = SQL .exe cutequery ("select * from users"); While (RS. next () {If (name2.equals (RS. getstring ("userid") & password2.equa Ls (RS. getstring ("upwd") & RS. getint ("if_forbid") = 0) {session. setattribute ("username", name2); out. println ("<script language = 'javascript '> window. location. href = 'index. JSP '; </SCRIPT> "); out. flush (); out. close ();} else if (name2.equals (RS. getstring ("userid") & password2.equals (RS. getstring ("upwd") & RS. getint ("if_forbid") = 1) {out. println ("this user has been banned !! "); Out. Flush (); Out. Close () ;}} out. println (" incorrect user name or password !! ");} Catch (exception e) {e. printstacktrace () ;}} public void dopost (httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {doget (request, response );}}
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