var error: NSError?
var dict: NSDictionary = [
    "1": 1,"2": "Two","3": false
]
 
let data = NSJSONSerialization.dataWithJSONObject(dict,options: NSJSONWritingOptions.PrettyPrinted,error: &error)
 
if let data = data {
    let json = NSString(data: data,encoding: NSUTF8StringEncoding)
    if let json = json {
        println(json)
    }
}

给定一个NSDictionary,它被序列化为NSData,然后转换为NSString.

执行转换的代码也可以更简洁地重写为：

斯威夫特3：

do {
        let jsonData = try JSONSerialization.data(withJSONObject: data)
        if let json = String(data: data,encoding: .utf8) {
            print(json)
        }
    } catch {
        print("something went wrong with parsing json")
    }

原始答案：

if let data = NSJSONSerialization.dataWithJSONObject(dict,error: &error) {
    if let json = NSString(data: data,encoding: NSUTF8StringEncoding) {
        println(json)
    }
}

请注意,为了使序列化起作用,字典必须包含有效的JSON键和值.