When users register to use ajax, user name test
package cn.hopetesting.com.servlet;2901583663
import com.fasterxml.jackson.databind.ObjectMapper;
import javax.print.attribute.standard.JobOriginatingUserName;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
/**
* @author newcityman
* @date 2019/9/18 - 21:49
*/
@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
void the doPost protected (the HttpServletRequest Request, the HttpServletResponse Response) throws ServletException, IOException {
the response.setContentType ( "file application / JSON; charset = UTF-. 8");
// the response.setContentType ( "text / HTML; charset = UTF-. 8") ;
// 1, acquiring parameters username
String = request.getParameter username ( "username");
// 2, the user calls the service layer determines whether there is a name
// expected server response data back to the format: {
// ( "userExist: to true , "msg", "this username is too popular, replace a"),
// ( "userExist: false," msg "," this username is available ")}
the Map <String, Object> = the Map new new HashMap < String, Object> ();
IF ( "tom."equals(username)){
//存在
map.put("userExist",true);
map.put ( "msg", "user name is too popular, replace a");
} the else {
// does not exist
map.put ( "userExist", to false);
map.put ( "msg", "this username available ");
}
// convert the map json, and passed to the client
// will map into JSON
ObjectMapper new new ObjectMapper Mapper = ();
// and delivered to the client
mapper.writeValue (response.getWriter ( ), Map);
}
protected void the doGet (the HttpServletRequest Request, the HttpServletResponse Response) throws ServletException, IOException {
this.doPost (Request, Response);
}
}
<! DOCTYPE HTML>
<HTML lang = "EN">
<head>
<Meta charset = "UTF-. 8">
<title> Register </ title>
<Script the src = "JS / jQuery-3.3.1.min.js "> </ Script>
<Script>
// page finishes loading
$ (function () {
// username bind to blur time
$ (" # username "). blur (function () {
// get username text entry box the value of
var username = $ (the this) .val ();
// send ajax request
// expected server response data back to the format: {
// ( "userExist: to true," MSG "," user name is too popular, replace a "),
// (" userExist: false, "msg", "this username is available")}
$.get("findUserServlet",{username:username},function (data) {
//判断userExist键的值是否存在
var span = $("#s_username");
if(data.userExist){
//存在
span.css("color","red");
span.html(data.msg);
}else{
//不存在
span.css("color","green");
span.html(data.msg);
}
}/*,"json"*/);
});
});
</script>
</head>
<body>
<input type="text" id="username" name="username"placeholder = "Please enter a username">
<span ID = "s_username"> </ span> a
<input type="password" id="password" name="passowrd" placeholder="请输入密码"><br/>
<input type="submit" value="提交">
</body>
</html>
package cn.hopetesting.com.servlet;2901583663
import com.fasterxml.jackson.databind.ObjectMapper;
import javax.print.attribute.standard.JobOriginatingUserName;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
/**
* @author newcityman
* @date 2019/9/18 - 21:49
*/
@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
void the doPost protected (the HttpServletRequest Request, the HttpServletResponse Response) throws ServletException, IOException {
the response.setContentType ( "file application / JSON; charset = UTF-. 8");
// the response.setContentType ( "text / HTML; charset = UTF-. 8") ;
// 1, acquiring parameters username
String = request.getParameter username ( "username");
// 2, the user calls the service layer determines whether there is a name
// expected server response data back to the format: {
// ( "userExist: to true , "msg", "this username is too popular, replace a"),
// ( "userExist: false," msg "," this username is available ")}
the Map <String, Object> = the Map new new HashMap < String, Object> ();
IF ( "tom."equals(username)){
//存在
map.put("userExist",true);
map.put ( "msg", "user name is too popular, replace a");
} the else {
// does not exist
map.put ( "userExist", to false);
map.put ( "msg", "this username available ");
}
// convert the map json, and passed to the client
// will map into JSON
ObjectMapper new new ObjectMapper Mapper = ();
// and delivered to the client
mapper.writeValue (response.getWriter ( ), Map);
}
protected void the doGet (the HttpServletRequest Request, the HttpServletResponse Response) throws ServletException, IOException {
this.doPost (Request, Response);
}
}
<! DOCTYPE HTML>
<HTML lang = "EN">
<head>
<Meta charset = "UTF-. 8">
<title> Register </ title>
<Script the src = "JS / jQuery-3.3.1.min.js "> </ Script>
<Script>
// page finishes loading
$ (function () {
// username bind to blur time
$ (" # username "). blur (function () {
// get username text entry box the value of
var username = $ (the this) .val ();
// send ajax request
// expected server response data back to the format: {
// ( "userExist: to true," MSG "," user name is too popular, replace a "),
// (" userExist: false, "msg", "this username is available")}
$.get("findUserServlet",{username:username},function (data) {
//判断userExist键的值是否存在
var span = $("#s_username");
if(data.userExist){
//存在
span.css("color","red");
span.html(data.msg);
}else{
//不存在
span.css("color","green");
span.html(data.msg);
}
}/*,"json"*/);
});
});
</script>
</head>
<body>
<input type="text" id="username" name="username"placeholder = "Please enter a username">
<span ID = "s_username"> </ span> a
<input type="password" id="password" name="passowrd" placeholder="请输入密码"><br/>
<input type="submit" value="提交">
</body>
</html>