ajax做登录请求成功了 已经进入后台为什么就是不走success

Question

后台代码（Java）：

    @RequestMapping(value = "loginUserNameAndUserPassword",method = RequestMethod.POST)
    public Admin loginUserNameAndUserPassword(
            @RequestParam("userName") String userName,
            @RequestParam("userPassword") String userPassword){
        if(userName != null && userPassword != null){
            Admin admin = adminService.readUserNameAndUserPassword(userName,userPassword);
            System.out.println(admin);
            return admin;
        }
        return null;
    }

前端代码：

$(function(){
    $("#loginBtn").click(function(){
        var userName = $("#userName").val()
        var userPassword = $("#userPassword").val()
        $.ajax({
            type: "POST",
            url: "http://localhost:8083/AdminController/loginUserNameAndUserPassword?userName="+userName+"&userPassword="+userPassword,
            dataType:"json",
            success:function (msg) {
                alert("成功")
                window.console.log("成功");
            },
            error: function () {
                alert("错误")
            }
        });
    })
})

Answer 1

你的ajax datatype 是json  要在controller 的public Admin loginUserNameAndUserPassword  改成 public @ResponseBody Admin loginUserNameAndUserPassword