使用 Swift 3 解析 JSON
Posted
技术标签:
【中文标题】使用 Swift 3 解析 JSON【英文标题】：Parse JSON with Swift 3 【发布时间】：2016-09-20 13:38:43 【问题描述】：我已经尝试让这个工作两周了。它正在使用 Swift 2 在 ios 9 上运行，但现在这似乎无缘无故地不起作用。我添加了print("[DEBUG] I was here 1/2/3/4") 来调试代码，它打印出来的只是[DEBUG] I was here 1。有任何想法吗？它让我发疯。
func downloadData()
//clear the arrays
arrayPosts = [String]()
arrayLinks = [String]()
arrayConditions = [String]()
arrayIDs = [String]()
//debug
print("[DEBUG] I was here: 1")
//baseURL is a string with URL to JSON Endpoint
let url = URL(string: baseURL)
URLSession.shared.dataTask(with:url!, completionHandler: (data, response, error) in
if error != nil
print("[ERROR] [DEBUG] Error with connection: \(error)")
else
do
//debug
print("[DEBUG] I was here: 2")
if let json = try JSONSerialization.jsonObject(with: data!, options:[.mutableContainers, .allowFragments]) as? [[String: Any]]
for item in json
//debug
print("[DEBUG] I was here: 3")
if let startTime = item["current_time"] as? Int
if self.defaults.integer(forKey: "startTime") == 0
self.defaults.set(startTime, forKey: "startTime")
if let posts = item["posts"] as? [[String: AnyObject]]
//debug
print("[DEBUG] I was here: 4")
for post in posts
if let text = post["text"] as? String
if let condition = post["conditions"] as? String
if let url = post["url"] as? String
if let id = post["id"] as? String
self.arrayPosts.append(text)
self.arrayConditions.append(condition)
self.arrayLinks.append(url)
self.arrayIDs.append(id)
catch
print("[ERROR] [DEBUG] Something went wrong during data download from the server.")
).resume()
这是 JSON DATA 以防万一：
"status": "ok",
"num_results": "4",
"current_time": 1474386061,
"user_time": 0,
"posts": [
"text": "If your shirt isn't tucked into your pants, then your pants are tucked into your shirt.",
"conditions": "4",
"url": "0",
"time": "0",
"id": "108"
,
"text": "Veteran Kills Himself in Parking Lot of V.A. Hospital on Long Island",
"conditions": "6",
"url": "http://www.nytimes.com/2016/08/25/nyregion/veteran-kills-himself-in-parking-lot-of-va-hospital-on-long-island.html",
"time": 1472076000,
"id": "1472076000"
,
"text": "Leaked Script Shows What Advisers Want Donald Trump to Say at Black Church",
"conditions": "6",
"url": "http://www.nytimes.com/2016/09/02/us/politics/donald-trump-black-voters-wayne-jackson.html",
"time": 1472767200,
"id": "1472767200"
,
"text": "Creepy Clown Sightings in South Carolina Cause a Frenzy",
"conditions": "6",
"url": "http://www.nytimes.com/2016/08/31/us/creepy-clown-sightings-in-south-carolina-cause-a-frenzy.html",
"time": 1472594400,
"id": "1472594400"
]
【问题讨论】：
我刚刚使用虚假 URL 进行了测试，结果显示为“[DEBUG] I was here: 2”。let url = URL(string: baseURL) 为零吗？
@EricAya 理论上应该。我再次运行它以防万一它停在“[DEBUG] I was here: 1”。可能是其他问题吗？就像我使用 http 而不是 https 的事实一样？
不，@Larme 不是
@MohanSingh 抱歉回复晚了。在你回答之前我已经解决了这个问题。还是谢谢。
【参考方案1】：
试试下面的代码：
import UIKit
class ViewController: UIViewController
var arrayPosts = [String]()
var arrayLinks = [String]()
var arrayConditions = [String]()
var arrayIDs = [String]()
override func viewDidLoad()
super.viewDidLoad()
self.downloadData()
func downloadData()
let url = NSURL(string: "http://getmydetails.pe.hu/test/parsejsonswift3.php") //Provided JSON data on my server. i don't know how longer it is present there!.
let request = NSMutableURLRequest(url: url! as URL)
let task = URLSession.shared.dataTask(with: request as URLRequest) data,response,error in
guard error == nil && data != nil else
print("Error:",error)
return
let httpStatus = response as? HTTPURLResponse
if httpStatus!.statusCode == 200
if data?.count != 0
let responseString = try! JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary //because JSON data started with dictionary. Not an array
let status = responseString["status"] as! String
if status == "ok"
print("Status is :", status)
let timevar = responseString["current_time"] //not specified as String or Int
print(String(describing: timevar)) // print by converting anyobject to string
if let posts = responseString["posts"] as? [AnyObject] // posts started with array
for post in posts
let text = post["text"] as! String //specify as String
print(text)
let condition = post["conditions"] as! String
let url = post["url"] as! String
let id = post["id"] as! String
DispatchQueue.main.sync
self.arrayPosts.append(text)
self.arrayConditions.append(condition)
self.arrayLinks.append(url)
self.arrayIDs.append(id)
//optional to check
self.afterJSON()
else
print("I could not find post array")
else
print("Status is not Okay!")
else
print("No data got from url!")
else
print("error httpstatus code is :",httpStatus!.statusCode)
task.resume()
func afterJSON()
print("Posts are:\n\t\t",arrayPosts)
print("Conditions are:\n\t\t",arrayConditions)
print("Links are:\n\t\t",arrayLinks)
print("ID's are:\n\t\t",arrayIDs)
override func didReceiveMemoryWarning()
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
输出如下图所示，
如果您感到困惑，请查看我的 video 适合您。
如有任何疑问，请在下方评论：D
【讨论】：
【参考方案2】：func downloadData()
//clear the arrays
arrayPosts = [String]()
arrayLinks = [String]()
arrayConditions = [String]()
arrayIDs = [String]()
//debug
print("[DEBUG] I was here: 1")
//baseURL is a string with URL to JSON Endpoint
let url = URL(string: baseURL)
let session = URLSession.shared
let task = session.dataTask(with: url!) (data:Data?, response:URLResponse?, error:Error?) in
if error != nil
print("[ERROR] [DEBUG] Error with connection: \(error)")
else
do
//debug
print("[DEBUG] I was here: 2")
if let json = try JSONSerialization.jsonObject(with: data!, options:[.mutableContainers, .allowFragments]) as? [[String: Any]]
for item in json
//debug
print("[DEBUG] I was here: 3")
if let startTime = item["current_time"] as? Int
if self.defaults.integer(forKey: "startTime") == 0
self.defaults.set(startTime, forKey: "startTime")
if let posts = item["posts"] as? [[String: AnyObject]]
//debug
print("[DEBUG] I was here: 4")
for post in posts
if let text = post["text"] as? String
if let condition = post["conditions"] as? String
if let url = post["url"] as? String
if let id = post["id"] as? String
self.arrayPosts.append(text)
self.arrayConditions.append(condition)
self.arrayLinks.append(url)
self.arrayIDs.append(id)
catch
print("[ERROR] [DEBUG] Something went wrong during data download from the server.")
task.resume()
【讨论】：
这似乎不起作用。它再次停在“[DEBUG] I was here 1”处。【参考方案3】：谢谢，我按照你的代码获取数据））
func getJSON()
let wUrl = "http://api.fixer.io/latest"
let Url = NSURL(string: wUrl)
let request = NSMutableURLRequest(url: Url! as URL)
let task = URLSession.shared.dataTask(with: request as URLRequest) data, response, error in
guard error == nil && data != nil else
print("Error:", error ?? "some error")
return
let httpStatus = response as? HTTPURLResponse
if httpStatus!.statusCode == 200
if data?.count != 0
let resposeString = try! JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary
let base = resposeString["base"] as? String
print(base ?? "")
let date = resposeString["date"] as? String
print(date ?? "")
let rates = resposeString["rates"] as! Dictionary<String, AnyObject>
for (key, value) in rates
print("\(key)->\(value)")
else
print("Data is emty")
else
print("error httpStatus code: ", httpStatus?.statusCode ?? "")
;task.resume()
【讨论】：
以上是关于使用 Swift 3 解析 JSON的主要内容，如果未能解决你的问题，请参考以下文章
如何使用 Alamofire 在 Swift 3 中解析 JSON？
使用 Alamofire 在 swift 3 中解析 Json