ASP.NET Web API构建一个简单的应用

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使用ASP.NET Web API构建一个简单的应用。

示例：使用ASP.NET Web API提供获取用户列表和用户信息接口。

1、在Models目录下创建用户信息类（UserModel.cs）

/// <summary>
/// 用户信息类
/// </summary>
public class UserModel
{
    /// <summary>
    /// 用户ID
    /// </summary>
    public int ID { get; set; }

    /// <summary>
    /// 用户名称
    /// </summary>
    public string Name { get; set; }

    /// <summary>
    /// 性别
    /// </summary>
    public string Sex { get; set; }
}

2、在Models目录下创建用户参数类（UserParam.cs）

/// <summary>
/// 用户参数类
/// </summary>
public class UserParam
{
    /// <summary>
    /// 用户ID
    /// </summary>
    public int ID { get; set; }

    /// <summary>
    /// 用户名称
    /// </summary>
    public string Name { get; set; }

    /// <summary>
    /// 性别
    /// </summary>
    public string Sex { get; set; }
}

3、创建API执行状态编码枚举（ApiStatusCode.cs）

/// <summary>
/// API执行状态编码枚举
/// </summary>
public enum ApiStatusCode
{
    /// <summary>
    /// 参数缺失或无效
    /// </summary>
    ParamInvalid = 1000,

    /// <summary>
    /// 操作成功
    /// </summary>
    Success = 2000,

    /// <summary>
    /// 系统异常
    /// </summary>
    SystemException = 5000,

    /// <summary>
    /// 操作失败
    /// </summary>
    Failed = 5500
}

4、在Models目录下创建Api返回结果类（ApiResultModel.cs）

/// <summary>
/// Api返回结果类
/// </summary>
public class ApiResultModel
{
    /// <summary>
    /// 状态码
    /// </summary>
    public ApiStatusCode StatusCode { get; set; }

    /// <summary>
    /// 返回消息描述
    /// </summary>
    public string Message { get; set; }

    /// <summary>
    /// 返回数据
    /// </summary>
    public object Data { get; set; }
}

5、在Controllers目录下创建WebApi控制器基类（BaseApiController.cs），并编写相关WebApi的公共处理方法。

/// <summary>
/// WebApi控制器基类
/// </summary>
public class BaseApiController : ApiController
{
    /// <summary>
    /// 获取当前请求的Token值
    /// </summary>
    public static string GetRequestToken()
    {
        string token = HttpContext.Current.Request.Headers["Access-Token"];
        return token;
    }

    /// <summary>
    /// 生成新Token
    /// </summary>
    /// <returns></returns>
    public static string CreateNewToken()
    {
        //TODO:生成新Token方法待完成
        string token = "12345";
        return token;
    }

    /// <summary>
    /// 获取POST请求Request中的参数
    /// </summary>
    public static string GetRequestParam()
    {
        using (StreamReader sr = new StreamReader(HttpContext.Current.Request.InputStream))
        {
            string reqParam = sr.ReadToEnd();
            return reqParam;
        }
    }

    /// <summary>
    /// 获取POST请求Request中的参数并反序列化为T对象
    /// </summary>
    public static T GetRequestParam<T>() where T : class,new()
    {
        using (StreamReader sr = new StreamReader(HttpContext.Current.Request.InputStream))
        {
            string reqParam = sr.ReadToEnd();

            if (string.IsNullOrWhiteSpace(reqParam))
            {
                return default(T);
            }
            return JsonConvert.DeserializeObject<T>(reqParam);
        }
    }

    /// <summary>
    /// 将对象转换为Json格式的HttpResponseMessage对象
    /// </summary>
    public static HttpResponseMessage ToResponseJson(ApiResultModel model)
    {
        string str = JsonConvert.SerializeObject(model);
        var result = new HttpResponseMessage
        {
            Content = new StringContent(str, Encoding.GetEncoding("UTF-8"), "application/json")
        };

        //生成新Token
        string token = CreateNewToken();

        //添加响应头信息
        result.Headers.Add("Access-Control-Expose-Headers", "Access-Token");
        result.Headers.Add("Access-Token", token);

        return result;
    }
}

6、在Controllers目录下创建用户控制器（UserController.cs），该控制器继承BaseApiController基类，并编写相关接口方法。

/// <summary>
/// 用户控制器
/// </summary>
public class UserController : BaseApiController
{
    /// <summary>
    /// 查询用户列表
    /// </summary>
    [HttpPost]
    public HttpResponseMessage QueryUserList()
    {
        ApiResultModel result = new ApiResultModel();

        //获取查询参数
        UserParam param = GetRequestParam<UserParam>();
        if (param == null)
        {
            result.StatusCode = ApiStatusCode.ParamInvalid;
            result.Message = "参数缺失或无效";
            result.Data = null;
            return ToResponseJson(result);
        }

        //获取用户数据列表
        List<UserModel> userList = GetUserData();

        //根据查询参数，筛选数据
        if (!String.IsNullOrEmpty(param.Name))
        {
            userList = userList.Where(a => a.Name == param.Name).ToList();
        }
        if (!String.IsNullOrEmpty(param.Sex))
        {
            userList = userList.Where(a => a.Sex == param.Sex).ToList();
        }

        //返回最终结果
        result.StatusCode = ApiStatusCode.Success;
        result.Message = "操作成功";
        result.Data = userList;
        return ToResponseJson(result);
    }

    /// <summary>
    /// 查询单个用户
    /// </summary>
    [HttpPost]
    public HttpResponseMessage QueryUserInfo()
    {
        ApiResultModel result = new ApiResultModel();

        //获取查询参数
        UserParam param = GetRequestParam<UserParam>();
        if (param == null)
        {
            result.StatusCode = ApiStatusCode.ParamInvalid;
            result.Message = "参数缺失或无效";
            result.Data = null;
            return ToResponseJson(result);
        }

        if (param.ID <= 0)
        {
            result.StatusCode = ApiStatusCode.ParamInvalid;
            result.Message = "无效的ID值参数";
            result.Data = null;
            return ToResponseJson(result);
        }

        //获取用户数据列表
        List<UserModel> userList = GetUserData();

        //根据查询参数，筛选数据
        UserModel user = userList.FirstOrDefault(a => a.ID == param.ID);

        //返回最终结果
        result.StatusCode = ApiStatusCode.Success;
        result.Message = "操作成功";
        result.Data = user;
        return ToResponseJson(result);
    }

    /// <summary>
    /// 获取用户数据列表
    /// </summary>
    private List<UserModel> GetUserData()
    {
        List<UserModel> result = new List<UserModel>();
        result.Add(new UserModel() { ID = 1, Name = "张三", Sex = "男" });
        result.Add(new UserModel() { ID = 2, Name = "李四", Sex = "女" });
        result.Add(new UserModel() { ID = 3, Name = "王五", Sex = "男" });
        result.Add(new UserModel() { ID = 4, Name = "孙六", Sex = "女" });
        return result;
    }
}

7、运行测试

这里测试第一个接口方法（查询用户列表），使用测试工具：Postman，如下图。

请求参数：

{
	"Name": "",
	"Sex": "男"
}

响应结果：

{
	"StatusCode": 2000,
	"Message": "操作成功",
	"Data": [{
			"ID": 1,
			"Name": "张三",
			"Sex": "男"
		},
		{
			"ID": 3,
			"Name": "王五",
			"Sex": "男"
		}
	]
}