本文目录一览：
如何设置webapi返回json或jsonp
ing System.Net;
using System.Net.Http.Formatting;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using System.Web;
using System.Net.Http;
using Newtonsoft.Json.Converters;
using System.Web.Http;
namespace Westwind.Web.WebApi
{
/// summary
/// Handles JsonP requests when requests are fired with text/javascript
/// /summary
public class JsonpFormatter : JsonMediaTypeFormatter
{
public JsonpFormatter()
{
SupportedMediaTypes.Add(new MediaTypeHeaderValue("application/json"));
SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/javascript"));
JsonpParameterName = "callback";
}
/// summary
/// Name of the query string parameter to look for
/// the jsonp function name
/// /summary
public string JsonpParameterName {get; set; }
/// summary
/// Captured name of the Jsonp function that the JSON call
/// is wrapped in. Set in GetPerRequestFormatter Instance
/// /summary
private string JsonpCallbackFunction;
webapi 如何返回json字符串？
方法一：(改配置法)
找到Global.asax文件，在Application_Start()方法中添加一句：
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
// 使api返回为json
GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();
}
怎么让webapi返回json
返回的时候封装成json即可。
参考： Student st1 = new Student(1, "dg", 18, new Date());
Student st2 = new Student(2, "dg", 18, new Date());
Student st3 = new Student(3, "dg", 18, new Date());
Student st4 = new Student(4, "dg", 18, new Date());
Student st5 = new Student(5, "dg", 18, new Date());
List li = new ArrayList();
JSONObject JO1 = new JSONObject(st1);
JSONObject JO2 = new JSONObject(st2);
JSONObject JO3 = new JSONObject(st3);
JSONObject JO4 = new JSONObject(st4);
JSONObject JO5 = new JSONObject(st5);
li.add(JO1);
li.add(JO2);
li.add(JO3);
li.add(JO4);
li.add(JO5);
JSONArray Ja = new JSONArray(li);
Map ma = new HashMap();
ma.put("Result", "OK");
ma.put("Records", Ja);
JSONObject js = new JSONObject(ma);
out.print(js);
返回结果：
{"Result":"OK","Records":[{"recordDate":"Fri Dec 16 17:54:39 CST 2011","name":"dg","age":18,"personId":1},{"recordDate":"Fri Dec 16 17:54:39 CST 2011","name":"dg","age":18,"personId":2},{"recordDate":"Fri Dec 16 17:54:39 CST 2011","name":"dg","age":18,"personId":3},{"recordDate":"Fri Dec 16 17:54:39 CST 2011","name":"dg","age":18,"personId":4},{"recordDate":"Fri Dec 16 17:54:39 CST 2011","name":"dg","age":18,"personId":5}]}
可以将存放Java对象的 列表 直接转化为 json 数组 或对象，不必要过分麻烦的转换。
从数据库取出后换：
SourceDao sd = new SourceDao();
JSONArray ja = new JSONArray(sd.query(content));
