Use Ajax in struts2 to verify whether a mailbox (user name) is registered

Action class:

Package COM. grace. myblog. view. action; import Java. io. printwriter; import javax. servlet. HTTP. httpservletrequest; import javax. servlet. HTTP. httpservletresponse; import Org. apache. struts2.servletactioncontext; import Org. springframework. stereotype. controller; import COM. grace. myblog. domain. user; @ controllerpublic class emailcheckaction {/*****/Private Static final long serialversionuid = 1l; Public String execute () throws exception {try {string responsetext = ""; httpservletrequest request = servletactioncontext. getrequest (); string email = request. getparameter ("email"); system. out. println ("---" + email); User user = registerservice. findbyemail (email); // query the database by email to determine whether the mailbox has been registered if (user = NULL) {responsetext = "2 ";} else {responsetext = "1";} httpservletresponse response = servletactioncontext. getresponse (); response. setcontenttype ("text/html; charset = UTF-8"); printwriter out = response. getwriter (); out. print (responsetext); out. flush (); out. close ();} catch (exception e) {e. printstacktrace ();} return NULL ;}}

Code in JS

 
Function checkusermail () {/* Email check Ajax */var email = document. getelementbyid ("email "). value; var xhr = ajaxfunction (); xhr. onreadystatechange = function () {If (xhr. readystate = 4) {If (xhr. status = 200) {var DATA = xhr. responsetext; // obtain the text if (Data = "1") {document. getelementbyid ("emailcheck "). innerhtml = "<font color = 'red'> this email address has been registered </font>"; return false;} else {document. getelementbyid ("emailcheck "). innerhtml =" Hi, this email has not been registered "; return true ;}}} xhr. Open (" get "," emailcheck. Action? Email = "+ email, true); xhr. setRequestHeader (" Content-Type "," application/X-WWW-form-urlencoded "); xhr. Send ();}
 

Function ajaxfunction () {var XMLHTTP; try {// Firefox, opera 8.0 +, Safari XMLHTTP = new XMLHttpRequest ();} catch (E) {try {// Internet Explorer XMLHTTP = new activexobject ("msxml2.xmlhttp");} catch (e) {try {XMLHTTP = new activexobject ("Microsoft. XMLHTTP ");} catch (e) {}} return XMLHTTP ;}
 

Sturts. xml configuration

 
<! -- Email check Ajax --> <action name = "emailcheck" class = "emailcheckaction">/* use the annotation method. Therefore, the class name is lowercase by default */</Action>
 

You only need to add the following line of code to the JSP page where you want to display the prompt.

 
<Div id = "emailcheck"> </div>