.Net基于MVC4 Web Api输出Json格式实例

本文实例讲述了.Net基于MVC4 Web Api输出Json格式的方法，。具体实现方法如下：

1、Global 中增加json输出

GlobalConfiguration.Configuration.Formatters.JsonFormatter.MediaTypeMappings.Add(new QueryStringMapping("json", "true", "application/json"));

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();
    //添加json 解析  使用方法 http://xxx/api/action?json=true
    GlobalConfiguration.Configuration.Formatters.JsonFormatter.MediaTypeMappings.Add(new QueryStringMapping("json", "true", "application/json"));
    WebApiConfig.Register(GlobalConfiguration.Configuration);
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);
}

2、Global 中删除xml解析

GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();
    WebApiConfig.Register(GlobalConfiguration.Configuration);
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);
    //删除xml的解析 当返回值是string 时 直接返回string不是json对象
    GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();
}

3、指定返回格式

新建方法 需要程序集：
System.Web.Extensions
public static HttpResponseMessage ToJson(Object obj)
{
    String str;
    if (obj is String || obj is Char)
    {
        str = obj.ToString();
    }
    else
    {
        var serializer = new JavaScriptSerializer();
        str = serializer.Serialize(obj);
    }
    var result = new HttpResponseMessage { Content = new StringContent(str, Encoding.GetEncoding("UTF-8"), "application/json") };
    return result;
}

 调用户方法转换为json对象输出

public HttpResponseMessage GetString(string name)
{
     return ToJson(name);
}

4、重写默认实现类 所有输出将被重新解析成 json

新建JsonContentNegotiator 类
public class JsonContentNegotiator : IContentNegotiator