请看下面的格式
{
"layer_id":"1Wn",
"name":"Example Place",
"latitude":"45.5037078163837",
"longitude":"-122.622699737549",
"span_longitude":"0.62",
"extra":{
"description":"Portland",
"url":"http://en.wikipedia.org/wiki/Portland"
}
}
如何使 JSON 请求形成这种格式