fix

Application/Exceptions/ApplicationException.cs

@@ -0,0 +1,16 @@
+namespace Application.Exceptions;
+
+/// <summary>
+/// 应用层异常基类
+/// </summary>
+public class ApplicationException : Exception
+{
+    public ApplicationException(string message) : base(message)
+    {
+    }
+
+    public ApplicationException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+}

Application/Exceptions/BusinessException.cs

@@ -0,0 +1,19 @@
+namespace Application.Exceptions;
+
+/// <summary>
+/// 业务逻辑异常（对应HTTP 500 Internal Server Error）
+/// </summary>
+/// <remarks>
+/// 用于业务操作失败、数据状态不一致等场景
+/// </remarks>
+public class BusinessException : ApplicationException
+{
+    public BusinessException(string message) : base(message)
+    {
+    }
+
+    public BusinessException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+}

Application/Exceptions/NotFoundException.cs

@@ -0,0 +1,11 @@
+namespace Application.Exceptions;
+
+/// <summary>
+/// 资源未找到异常（对应HTTP 404 Not Found）
+/// </summary>
+/// <remarks>
+/// 用于查询的资源不存在等场景
+/// </remarks>
+public class NotFoundException(string message) : ApplicationException(message)
+{
+}

Application/Exceptions/ValidationException.cs

@@ -0,0 +1,11 @@
+namespace Application.Exceptions;
+
+/// <summary>
+/// 业务验证异常（对应HTTP 400 Bad Request）
+/// </summary>
+/// <remarks>
+/// 用于参数验证失败、业务规则不满足等场景
+/// </remarks>
+public class ValidationException(string message) : ApplicationException(message)
+{
+}