content-type

      Ajax传值：

$.ajax({
           url:'dyn/hello',
           type:'POST',
           data:JSON.stringify(persons),
           dataType:'html',
           contentType:'application/json',
           success:function(data){
                alert(data);
           }
});

     服务连接：

    

URL url = new URL("http://localhost:8080/services/dsyw");
 HttpURLConnection connection = (HttpURLConnection) url.openConnection();
// 连接参数设置
connection.setRequestMethod("POST");//发送方式
connection.setRequestProperty("content-type", "text/xml;charset=utf-8");//数据格式
connection.setDoInput(true);
connection.setDoOutput(true);

// 发送请求
String soapXML = getXML("1111111");  
OutputStream os = connection.getOutputStream();  
os.write(soapXML.getBytes());
// 接收服务端响应
int responseCode = connection.getResponseCode();

由此可看出 contentType 决定了请求时的数据格式。

其他参考:http://blog.youkuaiyun.com/eyebrother/article/details/36007145