let jsonObject = try NSJSONSerialization.JSONObjectWithData(data,options: NSJSONReadingOptions.MutableContainers)
print(jsonObject)

let array = jsonObject as! NSArray

//读取数组中某个key所对应的所有值
print(array.valueForKey("text"))

//读取第一个元素
print(array[0])

//读取第一个元素的key对应的值
let text = array[0].valueForKey("text")
print(text)

//在使用if let语句的时候，swift会自动进行拆包
if let state = array[0].objectForKey("state") {
    print(state)
}

(
        {
        id = 1;
        state = closed;
        text = "Node 1";
    },{
        id = 2;
        state = open;
        text = "Node 2";
    },{
        id = 3;
        state = open;
        text = "Node 3";
    },{
        id = 4;
        state = open;
        text = "Node 4";
    }
)
(
    "Node 1","Node 2","Node 3","Node 4"
)
{
    id = 1;
    state = closed;
    text = "Node 1";
}
Optional(Node 1)
closed