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说到AOP编程，可能大部分人是即熟悉又显得陌生。
AOP的作用就是横切关注点，然后将分离后的关注点以面的形式来呈现，这是概念性的说法，举个列子来说明吧。
比如说有个API接口处理场景是提交订单，在我们提交订单的时候，首先客户端要对用户提交的数据进行合法性验证，验证通过后，数据发送到服务端，因客户端一切操作都是不可信的，必然服务端在录入订单信息之前也需要对数据合法性进行验证。
针对上述问题我们可以这样子来编码
首先定义订单表单参数实体对象：
1 /// <summary> 2 /// Post表单参数 3 /// </summary> 4 public class FromOrderInfo 5 { 6 /// <summary> 7 /// 商品名称 8 /// </summary> 9 public string ShopName { get; set; } 10 /// <summary> 11 /// 手机号 12 /// </summary> 13 [ValidateMobile(ErrorMessage = "请输入正确格式的手机号")]//自定义验证规则 14 public string Mobile { get; set; } 15 /// <summary> 16 /// Address 17 /// </summary> 18 [ValidateMaxLength(20,ErrorMessage = "Address字符超过指定长度")] 19 public string Address { get; set; } 20 }
自定义验证如下：
1 /// <summary> 2 /// 验证字符长度是否超过指定长度 3 /// </summary> 4 public class ValidateMaxLengthAttribute : ValidationAttribute 5 { 6 private readonly int MaxLength; 7 8 public ValidateMaxLengthAttribute(int maxLength) 9 : base("{0}的字符太多了!") 10 { 11 MaxLength = maxLength; 12 } 13 14 protected override ValidationResult IsValid(object value, ValidationContext validationContext) 15 { 16 if (value != null) 17 { 18 string content = value.ToString(); 19 int leng = StringTool.GetStringLength(content); 20 if (leng > MaxLength) 21 { 22 string errorMessage = FormatErrorMessage(validationContext.DisplayName); 23 return new ValidationResult(errorMessage); 24 } 25 } 26 return ValidationResult.Success; 27 } 28 } 29 30 /// <summary> 31 /// 验证手机号 32 /// </summary> 33 public class ValidateMobileAttribute : ValidationAttribute 34 { 35 public ValidateMobileAttribute() 36 : base("{0}应输入11位手机号!") 37 { 38 } 39 protected override ValidationResult IsValid(object value, ValidationContext validationContext) 40 { 41 if (value != null) 42 { 43 string content = value.ToString(); 44 if (!RegexTool.IsMobile(content)) 45 { 46 string errorMessage = FormatErrorMessage(validationContext.DisplayName); 47 return new ValidationResult(errorMessage); 48 } 49 } 50 return ValidationResult.Success; 51 } 52 }
订单API接口：
1 [CHKFormInput(typeof(FromOrderInfo))] 2 public HttpResponseMessage TestOrder([FromBody] FromInfo info) 3 { 4 var challengeMessage = new System.Net.Http.HttpResponseMessage(System.Net.HttpStatusCode.OK); 5 6 challengeMessage = new ResponseMessage<string>("json").Response("下单成功"); 7 return challengeMessage; 8 9 } 10 11 /// <summary> 12 /// Post表单参数 13 /// </summary> 14 public class FromInfo 15 { 16 /// <summary> 17 /// Json数据对象 18 /// </summary> 19 public string JsonFormat { get; set; } 20 }
定义过滤器：
1 /// <summary> 2 /// 验证表单参数 3 /// </summary> 4 public class CHKFormInput : ActionFilterAttribute 5 { 6 private Type _type; 7 /// <summary> 8 /// 构造函数 9 /// </summary> 10 /// <param name="type">表单参数验证对象</param> 11 public CHKFormInput(Type type = null) 12 { 13 if (type != null) 14 { 15 this._type = type; 16 } 17 } 18 public override void OnActionExecuting(HttpActionContext actionContext)//执行action动作所需执行的操作 19 { 20 #region 检查表单参数是否合法 21 var challengeMessage = new System.Net.Http.HttpResponseMessage(System.Net.HttpStatusCode.OK); 22 ErrorResponse errorMsgConvertjson = new ErrorResponse();//返回错误信息string errorMsg = string.Empty; 23 try 24 { 25 if (actionContext == null) 26 { 27 throw new System.Web.Http.HttpResponseException(challengeMessage); 28 } 29 if (ProjectRequest.IsPost())//验证是否POST请求 30 { 31 var task = actionContext.Request.Content.ReadAsStreamAsync(); 32 var content = string.Empty; 33 using (System.IO.Stream sm = task.Result) 34 { 35 if (sm != null) 36 { 37 sm.Seek(0, SeekOrigin.Begin); 38 int len = (int)sm.Length; 39 byte[] inputByts = new byte[len]; 40 sm.Read(inputByts, 0, len); 41 sm.Close(); 42 content = Encoding.UTF8.GetString(inputByts); 43 } 44 } 45 var m = JsonTool.JsonToEntity<FromInfo>(content); 46 var Json = Serializer.Deserialize(m.JsonFormat, _type); 47 new TryValidateModelTool().TryValidateModel(Json, ref errorMsg); 48 if(!string.IsNullOrEmpty(errorMsg)) 49 { 50 errorMsgConvertjson.Message = errorMsg; 51 errorMsgConvertjson.State = CallBackServer.InputError; 52 challengeMessage = new ResponseMessage<ErrorResponse>("json").Response(errorMsgConvertjson); 53 actionContext.Response = challengeMessage; 54 } 55 56 } 57 58 } 59 catch (Exception ex) 60 { 61 } 62 finally 63 { 64 } 65 base.OnActionExecuting(actionContext); 66 #endregion 67 } 68 }
实体对像属性验证类：
1 /// <summary> 2 /// 利用特性验证实体对象参数合法性 3 /// </summary> 4 public class TryValidateModelTool : ApiController 5 { 6 /// <summary> 7 /// 利用特性验证实体对象参数合法性 8 /// </summary> 9 /// <param name="model">对象</param> 10 /// <param name="errorMsg">错误信息</param> 11 /// <returns></returns> 12 public bool TryValidateModel(object model, ref string errorMsg) 13 { 14 return TryValidateModel(model, null /* prefix */, ref errorMsg); 15 } 16 17 18 19 20 /// <summary> 21 /// 利用特性验证实体对象参数合法性 22 /// </summary> 23 /// <param name="model">对象</param> 24 /// <param name="errorMsg">错误信息</param> 25 /// <returns></returns> 26 public bool TryValidateModel(object model, string prefix, ref string errorMsg) 27 { 28 if (model == null) 29 { 30 throw new ArgumentNullException("model"); 31 } 32 33 ModelMetadata metadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, model.GetType()); 34 var t = new ModelBindingExecutionContext(new HttpContextWrapper(HttpContext.Current), new System.Web.ModelBinding.ModelStateDictionary()); 35 List<string> errorMsgList = new List<string>(); 36 foreach (ModelValidationResult validationResult in ModelValidator.GetModelValidator(metadata, t).Validate(null)) 37 { 38 ModelState.AddModelError(validationResult.MemberName, validationResult.Message); 39 errorMsgList.Add(validationResult.Message); 40 } 41 errorMsg = string.Join(",", errorMsgList); 42 return ModelState.IsValid; 43 } 44 }
至此整个AOP过滤器编码全部完成，在用户提交表单之前，API接口会首先进入CHKFormInput 过滤器验证参数合法性，如验证失败，将不进入提交订单的API接口
感谢您的阅读！
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原文地址：http://www.cnblogs.com/dzycwy/p/5335778.html
