fix: return structured JSON on auth failure for login error message

src/main/java/com/freedom/admin/config/MyAuthenticationFailureHandler.java

@@ -1,6 +1,10 @@
 package com.freedom.admin.config;
 
+import com.alibaba.fastjson.JSON;
+import com.freedom.admin.common.Result;
 import org.springframework.security.authentication.BadCredentialsException;
+import org.springframework.security.authentication.DisabledException;
+import org.springframework.security.authentication.LockedException;
 import org.springframework.security.core.AuthenticationException;
 import org.springframework.security.web.authentication.AuthenticationFailureHandler;
 import org.springframework.stereotype.Component;
@@ -21,15 +25,23 @@ public class MyAuthenticationFailureHandler implements AuthenticationFailureHand
     public void onAuthenticationFailure(HttpServletRequest request,
                                         HttpServletResponse response,
                                         AuthenticationException e) throws IOException {
-        //修改编码格式
-        request.setCharacterEncoding("utf-8");
-        response.setContentType("application/json");
+        // 修改编码格式
+        response.setCharacterEncoding("utf-8");
+        response.setContentType("application/json;charset=utf-8");
 
-        if (e instanceof BadCredentialsException){
-            response.getWriter().write("用户名或密码错误");
-        }else {
-            response.getWriter().write("登录失败！");
+        String message;
+        if (e instanceof BadCredentialsException) {
+            message = "用户名或密码错误";
+        } else if (e instanceof LockedException) {
+            message = "账号已被锁定，请联系管理员";
+        } else if (e instanceof DisabledException) {
+            message = "账号已被禁用，请联系管理员";
+        } else {
+            message = "登录失败，请稍后重试";
         }
-
+        // 返回结构化 JSON（HTTP 200 + 业务码），前端依据 message 提示用户；
+        // code 415 为前端模板预留的凭据类错误码
+        Result result = Result.error().code(415).message(message);
+        response.getWriter().write(JSON.toJSONString(result));
     }
 }