使用 Swift 读取 JSON 文件
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Reading in a JSON File Using Swift
提问by Krivvenz
I'm really struggling with trying to read a JSON file into Swift so I can play around with it. I've spent the best part of 2 days re-searching and trying different methods but no luck as of yet so I have signed up to StackOverFlow to see if anyone can point me in the right direction.....
我真的很难尝试将 JSON 文件读入 Swift 以便我可以使用它。我花了 2 天的大部分时间重新搜索并尝试不同的方法，但到目前为止还没有运气，所以我注册了 StackOverFlow，看看是否有人可以为我指明正确的方向.....
My JSON file is called test.json and contains the following:
我的 JSON 文件名为 test.json，包含以下内容：
{
"person":[
{
"name": "Bob",
"age": "16",
"employed": "No"
},
{
"name": "Vinny",
"age": "56",
"employed": "Yes"
}
]
}
The file is stored in the documents directly and I access it using the following code:
该文件直接存储在文档中，我使用以下代码访问它：
let file = "test.json"
let dirs : String[] = NSSearchPathForDirectoriesInDomains(
NSSearchpathDirectory.DocumentDirectory,
NSSearchPathDomainMask.AllDomainMask,
true) as String[]
if (dirs != nil) {
let directories: String[] = dirs
let dir = directories[0]
let path = dir.stringByAppendingPathComponent(file)
}
var jsonData = NSData(contentsOfFile:path, options: nil, error: nil)
println("jsonData \(jsonData)" // This prints what looks to be JSON encoded data.
var jsonDict = NSJSONSerialization.JSONObjectWithData(jsonData, options: nil, error: nil) as? NSDictionary
println("jsonDict \(jsonDict)") - This prints nil.....
If anyone can just give me a push in the right direction on how I can de-serialize the JSON file and put it in an accessible Swift object I will be eternally grateful!
如果有人能在正确的方向上推动我如何反序列化 JSON 文件并将其放入可访问的 Swift 对象中，我将永远感激！
Kind Regards,
亲切的问候，
Krivvenz.
克里夫文茨。
回答by Abhishek
Follow the below code :
按照下面的代码：
if let path = NSBundle.mainBundle().pathForResource("test", ofType: "json")
{
if let jsonData = NSData(contentsOfFile: path, options: .DataReadingMappedIfSafe, error: nil)
{
if let jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers, error: nil) as? NSDictionary
{
if let persons : NSArray = jsonResult["person"] as? NSArray
{
// Do stuff
}
}
}
}
The array "persons" will contain all data for key person. Iterate throughs to fetch it.
数组“persons”将包含关键人物的所有数据。遍历以获取它。
Swift 4.0:
斯威夫特 4.0：
if let path = Bundle.main.path(forResource: "test", ofType: "json") {
do {
let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .mappedIfSafe)
let jsonResult = try JSONSerialization.jsonObject(with: data, options: .mutableLeaves)
if let jsonResult = jsonResult as? Dictionary<String, AnyObject>, let person = jsonResult["person"] as? [Any] {
// do stuff
}
} catch {
// handle error
}
}
回答by Aks
If anyone is looking for SwiftyJSONAnswer:
Update:
For Swift 3/4:
如果有人正在寻找SwiftyJSON答案：
更新：
对于Swift 3/4：
if let path = Bundle.main.path(forResource: "assets/test", ofType: "json") {
do {
let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .alwaysMapped)
let jsonObj = try JSON(data: data)
print("jsonData:\(jsonObj)")
} catch let error {
print("parse error: \(error.localizedDescription)")
}
} else {
print("Invalid filename/path.")
}
回答by yarlg
Swift 4 using Decodable
Swift 4 使用可解码
struct ResponseData: Decodable {
var person: [Person]
}
struct Person : Decodable {
var name: String
var age: String
var employed: String
}
func loadJson(filename fileName: String) -> [Person]? {
if let url = Bundle.main.url(forResource: fileName, withExtension: "json") {
do {
let data = try Data(contentsOf: url)
let decoder = JSONDecoder()
let jsonData = try decoder.decode(ResponseData.self, from: data)
return jsonData.person
} catch {
print("error:\(error)")
}
}
return nil
}
Swift 3
斯威夫特 3
func loadJson(filename fileName: String) -> [String: AnyObject]? {
if let url = Bundle.main.url(forResource: fileName, withExtension: "json") {
do {
let data = try Data(contentsOf: url)
let object = try JSONSerialization.jsonObject(with: data, options: .allowFragments)
if let dictionary = object as? [String: AnyObject] {
return dictionary
}
} catch {
print("Error!! Unable to parse \(fileName).json")
}
}
return nil
}
回答by ben
Xcode 8 Swift 3read json from file update:
Xcode 8 Swift 3从文件更新中读取 json：
if let path = Bundle.main.path(forResource: "userDatabseFakeData", ofType: "json") {
do {
let jsonData = try NSData(contentsOfFile: path, options: NSData.ReadingOptions.mappedIfSafe)
do {
let jsonResult: NSDictionary = try JSONSerialization.jsonObject(with: jsonData as Data, options: JSONSerialization.ReadingOptions.mutableContainers) as! NSDictionary
if let people : [NSDictionary] = jsonResult["person"] as? [NSDictionary] {
for person: NSDictionary in people {
for (name,value) in person {
print("\(name) , \(value)")
}
}
}
} catch {}
} catch {}
}
回答by Nick Graham
Updated names for Swift 3.0
Swift 3.0 的更新名称
Based on Abhishek's answerand Druva's answer
func loadJson(forFilename fileName: String) -> NSDictionary? {
if let url = Bundle.main.url(forResource: fileName, withExtension: "json") {
if let data = NSData(contentsOf: url) {
do {
let dictionary = try JSONSerialization.jsonObject(with: data as Data, options: .allowFragments) as? NSDictionary
return dictionary
} catch {
print("Error!! Unable to parse \(fileName).json")
}
}
print("Error!! Unable to load \(fileName).json")
}
return nil
}
回答by NeverwinterMoon
Simplifying the example provided by Peter Kreinz. Works with Swift 4.2.
简化 Peter Kreinz 提供的示例。适用于 Swift 4.2。
The extension function:
扩展功能：
extension Decodable {
static func parse(jsonFile: String) -> Self? {
guard let url = Bundle.main.url(forResource: jsonFile, withExtension: "json"),
let data = try? Data(contentsOf: url),
let output = try? JSONDecoder().decode(self, from: data)
else {
return nil
}
return output
}
}
The example model:
示例模型：
struct Service: Decodable {
let name: String
}
The example usage:
示例用法：
/// service.json
/// { "name": "Home & Garden" }
guard let output = Service.parse(jsonFile: "service") else {
// do something if parsing failed
return
}
// use output if all good
The example will work with arrays, too:
该示例也适用于数组：
/// services.json
/// [ { "name": "Home & Garden" } ]
guard let output = [Service].parse(jsonFile: "services") else {
// do something if parsing failed
return
}
// use output if all good
Notice how we don't provide any unnecessary generics, thus we don't need to cast the result of parse.
请注意我们如何不提供任何不必要的泛型，因此我们不需要转换解析的结果。
回答by Ashok R
Swift 3.0, Xcode 8, iOS 10
斯威夫特 3.0、Xcode 8、iOS 10
if let path = Bundle.main.url(forResource: "person", withExtension: "json") {
do {
let jsonData = try Data(contentsOf: path, options: .mappedIfSafe)
do {
if let jsonResult = try JSONSerialization.jsonObject(with: jsonData, options: JSONSerialization.ReadingOptions(rawValue: 0)) as? NSDictionary {
if let personArray = jsonResult.value(forKey: "person") as? NSArray {
for (_, element) in personArray.enumerated() {
if let element = element as? NSDictionary {
let name = element.value(forKey: "name") as! String
let age = element.value(forKey: "age") as! String
let employed = element.value(forKey: "employed") as! String
print("Name: \(name), age: \(age), employed: \(employed)")
}
}
}
}
} catch let error as NSError {
print("Error: \(error)")
}
} catch let error as NSError {
print("Error: \(error)")
}
}
Output:
输出：
Name: Bob, age: 16, employed: No
Name: Vinny, age: 56, employed: Yes
回答by kjm
Swift 2.1 answer (based on Abhishek's) :
Swift 2.1 答案（基于 Abhishek 的）：
if let path = NSBundle.mainBundle().pathForResource("test", ofType: "json") {
do {
let jsonData = try NSData(contentsOfFile: path, options: NSDataReadingOptions.DataReadingMappedIfSafe)
do {
let jsonResult: NSDictionary = try NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers) as! NSDictionary
if let people : [NSDictionary] = jsonResult["person"] as? [NSDictionary] {
for person: NSDictionary in people {
for (name,value) in person {
print("\(name) , \(value)")
}
}
}
} catch {}
} catch {}
}
回答by will.fiset
Here is my solution using SwiftyJSON
这是我使用SwiftyJSON 的解决方案
if let path : String = NSBundle.mainBundle().pathForResource("filename", ofType: "json") {
if let data = NSData(contentsOfFile: path) {
let json = JSON(data: data)
}
}
回答by Abdulaziz Noor
This worked great with me
这对我很有用
func readjson(fileName: String) -> NSData{
let path = NSBundle.mainBundle().pathForResource(fileName, ofType: "json")
let jsonData = NSData(contentsOfMappedFile: path!)
return jsonData!
}
