Ajax成功函数在java类响应之前触发(Ajax success function firing before java class responds)

我正在使用ajax创建一个登录函数，并且遇到成功函数（SuccessLogin）在获取ajax响应之前触发的问题。我从eclipse运行代码作为谷歌网络应用程序，我可以看到调试java类文件，javascript在调试器捕获类文件中的断点之前，从类失败的成功响应警告。我现在只编写了几个月的代码，所以我确信这是我的一个愚蠢的小错误。

$(document).ready(function() { sessionChecker() // sign in $('#signInForm').click(function () { $().button('loading') var email = $('#user_username').val(); sessionStorage.email = $('#user_username').val(); var password= $('#user_password').val(); var SignInRequest = { type: "UserLoginRequest", email: email, password: password } var data= JSON.stringify(SignInRequest); //disabled all the text fields $('.text').attr('disabled','true'); //start the ajax $.ajax({ url: "/resources/user/login", type: "POST", data: data, cache: false, success: successLogin(data) }); }); //if submit button is clicked $('#Register').click(function () { $().button('loading') var email = $('#email').val(); if ($('#InputPassword').val()== $('#ConfirmPassword').val()) { var password= $('input[id=InputPassword]').val(); } else {alert("Passwords do not match"); return ;} var UserRegistrationRequest = { type: "UserRegistrationRequest", email: email, password: password } var data= JSON.stringify(UserRegistrationRequest); //disabled all the text fields $('.text').attr('disabled','true'); //start the ajax $.ajax({ url: "/resources/user/register", type: "POST", data: data, cache: false, success: function (data) { if (data.success==true) { //hide the form $('form').fadeOut('slow'); //show the success message $('.done').fadeIn('slow'); } else alert('data.errorReason'); } }); return false; }); }); function successLogin (data){ if (data.success) { sessionStorage.userID= data.userID var userID = data.userID sessionChecker(userID); } else alert(data.errorReason); } //session check function sessionChecker(uid) { if (sessionStorage.userID!= null){ var userID = sessionStorage.userID }; if (userID != null){ $('#user').append(userID) $('#fat-menu_1').fadeOut('slow') $('#fat-menu_2').append(sessionStorage.email).fadeIn('slow') }; }

I am creating a login function with ajax and am having an issue where the success function (SuccessLogin) fires before getting an ajax response. I am running the code as google web app from eclipse and I can see when debugging the java class file, that the javascript is throwing an alert for the success response from the class being false before the debugger catches the break point in the class file. I have only been writing code for a couple months now so I am sure its a stupid little error on my part.

$(document).ready(function() { sessionChecker() // sign in $('#signInForm').click(function () { $().button('loading') var email = $('#user_username').val(); sessionStorage.email = $('#user_username').val(); var password= $('#user_password').val(); var SignInRequest = { type: "UserLoginRequest", email: email, password: password } var data= JSON.stringify(SignInRequest); //disabled all the text fields $('.text').attr('disabled','true'); //start the ajax $.ajax({ url: "/resources/user/login", type: "POST", data: data, cache: false, success: successLogin(data) }); }); //if submit button is clicked $('#Register').click(function () { $().button('loading') var email = $('#email').val(); if ($('#InputPassword').val()== $('#ConfirmPassword').val()) { var password= $('input[id=InputPassword]').val(); } else {alert("Passwords do not match"); return ;} var UserRegistrationRequest = { type: "UserRegistrationRequest", email: email, password: password } var data= JSON.stringify(UserRegistrationRequest); //disabled all the text fields $('.text').attr('disabled','true'); //start the ajax $.ajax({ url: "/resources/user/register", type: "POST", data: data, cache: false, success: function (data) { if (data.success==true) { //hide the form $('form').fadeOut('slow'); //show the success message $('.done').fadeIn('slow'); } else alert('data.errorReason'); } }); return false; }); }); function successLogin (data){ if (data.success) { sessionStorage.userID= data.userID var userID = data.userID sessionChecker(userID); } else alert(data.errorReason); } //session check function sessionChecker(uid) { if (sessionStorage.userID!= null){ var userID = sessionStorage.userID }; if (userID != null){ $('#user').append(userID) $('#fat-menu_1').fadeOut('slow') $('#fat-menu_2').append(sessionStorage.email).fadeIn('slow') }; }

最满意答案

success: successLogin(data)

函数调用和函数定义之间存在差异：

函数定义使用function关键字并包含函数体{...} 函数调用将括号（参数列表）附加到函数名称，并实际调用函数以返回值

如果为属性分配函数调用，它将返回一个值，该值将是存储的值。为了避免这种情况，如果你的函数没有采用任何参数你可以使用函数名，或者你的函数确实采用了一个参数，将你的函数调用嵌入到另一个函数的定义中：

无参数： success: successLogin 有参数： success: function() { successLogin(data); } success: function() { successLogin(data); }

success: successLogin(data)

There's a difference between a function call and a function definition:

A function definion uses the function keyword and contains a function body {...} A function call appends parentheses (argument list) to the function name and actually calls the function to return a value

If you assign a function call to the property, it will return a value and that will be what is stored. To avoid this, if your function does not take any parameters you can use the function name, or if your function does take a parameter, embed your function call in another function's definition:

No parameter: success: successLogin Has parameter: success: function() { successLogin(data); }

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