在 Swift 中将字典转换为 JSON
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/29625133/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Convert Dictionary to JSON in Swift
提问by Orkhan Alizade
I have create the next Dictionary:
我已经创建了下一个字典：
var postJSON = [ids[0]:answersArray[0], ids[1]:answersArray[1], ids[2]:answersArray[2]] as Dictionary
and I get:
我得到：
[2: B, 1: A, 3: C]
So, how can I convert it to JSON?
那么，如何将其转换为 JSON？
回答by Eric Aya
Swift 3.0
斯威夫特 3.0
With Swift 3, the name of NSJSONSerializationand its methods have changed, according to the Swift API Design Guidelines.
NSJSONSerialization根据Swift API 设计指南，在 Swift 3 中， 的名称及其方法已经更改。
let dic = ["2": "B", "1": "A", "3": "C"]
do {
let jsonData = try JSONSerialization.data(withJSONObject: dic, options: .prettyPrinted)
// here "jsonData" is the dictionary encoded in JSON data
let decoded = try JSONSerialization.jsonObject(with: jsonData, options: [])
// here "decoded" is of type `Any`, decoded from JSON data
// you can now cast it with the right type
if let dictFromJSON = decoded as? [String:String] {
// use dictFromJSON
}
} catch {
print(error.localizedDescription)
}
Swift 2.x
斯威夫特 2.x
do {
let jsonData = try NSJSONSerialization.dataWithJSONObject(dic, options: NSJSONWritingOptions.PrettyPrinted)
// here "jsonData" is the dictionary encoded in JSON data
let decoded = try NSJSONSerialization.JSONObjectWithData(jsonData, options: [])
// here "decoded" is of type `AnyObject`, decoded from JSON data
// you can now cast it with the right type
if let dictFromJSON = decoded as? [String:String] {
// use dictFromJSON
}
} catch let error as NSError {
print(error)
}
Swift 1
斯威夫特 1
var error: NSError?
if let jsonData = NSJSONSerialization.dataWithJSONObject(dic, options: NSJSONWritingOptions.PrettyPrinted, error: &error) {
if error != nil {
println(error)
} else {
// here "jsonData" is the dictionary encoded in JSON data
}
}
if let decoded = NSJSONSerialization.JSONObjectWithData(jsonData, options: nil, error: &error) as? [String:String] {
if error != nil {
println(error)
} else {
// here "decoded" is the dictionary decoded from JSON data
}
}
回答by Duncan C
You are making a wrong assumption. Just because the debugger/Playground shows your dictionary in square brackets (which is how Cocoa displays dictionaries) that does not mean that is the way the JSON output is formatted.
你在做一个错误的假设。仅仅因为调试器/Playground 在方括号中显示您的字典（这就是 Cocoa 显示字典的方式），并不意味着这是 JSON 输出的格式化方式。
Here is example code that will convert a dictionary of strings to JSON:
这是将字符串字典转换为 JSON 的示例代码：
Swift 3 version:
斯威夫特 3 版本：
import Foundation
let dictionary = ["aKey": "aValue", "anotherKey": "anotherValue"]
if let theJSONData = try? JSONSerialization.data(
withJSONObject: dictionary,
options: []) {
let theJSONText = String(data: theJSONData,
encoding: .ascii)
print("JSON string = \(theJSONText!)")
}
To display the above in "pretty printed" format you'd change the options line to:
要以“漂亮打印”格式显示上述内容，您需要将选项行更改为：
options: [.prettyPrinted]
Or in Swift 2 syntax:
或者在 Swift 2 语法中：
import Foundation
let dictionary = ["aKey": "aValue", "anotherKey": "anotherValue"]
let theJSONData = NSJSONSerialization.dataWithJSONObject(
dictionary ,
options: NSJSONWritingOptions(0),
error: nil)
let theJSONText = NSString(data: theJSONData!,
encoding: NSASCIIStringEncoding)
println("JSON string = \(theJSONText!)")
The output of that is
它的输出是
"JSON string = {"anotherKey":"anotherValue","aKey":"aValue"}"
Or in pretty format:
或者以漂亮的格式：
{
"anotherKey" : "anotherValue",
"aKey" : "aValue"
}
The dictionary is enclosed in curly braces in the JSON output, just as you'd expect.
正如您所期望的那样，字典包含在 JSON 输出中的花括号中。
EDIT:
编辑：
In Swift 3/4 syntax, the code above looks like this:
在 Swift 3/4 语法中，上面的代码如下所示：
let dictionary = ["aKey": "aValue", "anotherKey": "anotherValue"]
if let theJSONData = try? JSONSerialization.data(
withJSONObject: dictionary,
options: .prettyPrinted
),
let theJSONText = String(data: theJSONData,
encoding: String.Encoding.ascii) {
print("JSON string = \n\(theJSONText)")
}
}
回答by Ryan H
Swift 5:
斯威夫特 5：
let dic = ["2": "B", "1": "A", "3": "C"]
let encoder = JSONEncoder()
if let jsonData = try? encoder.encode(dic) {
if let jsonString = String(data: jsonData, encoding: .utf8) {
print(jsonString)
}
}
Note that keys and values must implement Codable. Strings, Ints, and Doubles (and more) are already Codable. See Encoding and Decoding Custom Types.
请注意，键和值必须实现Codable. 字符串、整数和双精度（以及更多）已经是Codable. 请参阅编码和解码自定义类型。
回答by user3182143
My answer for your question is below
我对你的问题的回答如下
let dict = ["0": "ArrayObjectOne", "1": "ArrayObjecttwo", "2": "ArrayObjectThree"]
var error : NSError?
let jsonData = try! NSJSONSerialization.dataWithJSONObject(dict, options: NSJSONWritingOptions.PrettyPrinted)
let jsonString = NSString(data: jsonData, encoding: NSUTF8StringEncoding)! as String
print(jsonString)
Answer is
答案是
{
"0" : "ArrayObjectOne",
"1" : "ArrayObjecttwo",
"2" : "ArrayObjectThree"
}
回答by Andrey Gordeev
Sometimes it's necessary to print out server's response for debugging purposes. Here's a function I use:
有时为了调试目的，有必要打印出服务器的响应。这是我使用的一个函数：
extension Dictionary {
var json: String {
let invalidJson = "Not a valid JSON"
do {
let jsonData = try JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
return String(bytes: jsonData, encoding: String.Encoding.utf8) ?? invalidJson
} catch {
return invalidJson
}
}
func printJson() {
print(json)
}
}
Example of use:
使用示例：
(lldb) po dictionary.printJson()
{
"InviteId" : 2,
"EventId" : 13591,
"Messages" : [
{
"SenderUserId" : 9514,
"MessageText" : "test",
"RecipientUserId" : 9470
},
{
"SenderUserId" : 9514,
"MessageText" : "test",
"RecipientUserId" : 9470
}
],
"TargetUserId" : 9470,
"InvitedUsers" : [
9470
],
"InvitingUserId" : 9514,
"WillGo" : true,
"DateCreated" : "2016-08-24 14:01:08 +00:00"
}
回答by thexande
Swift 4 Dictionaryextension.
斯威夫特 4Dictionary扩展。
extension Dictionary {
var jsonStringRepresentation: String? {
guard let theJSONData = try? JSONSerialization.data(withJSONObject: self,
options: [.prettyPrinted]) else {
return nil
}
return String(data: theJSONData, encoding: .ascii)
}
}
回答by Bilal
Swift 3:
斯威夫特3：
let jsonData = try? JSONSerialization.data(withJSONObject: dict, options: [])
let jsonString = String(data: jsonData!, encoding: .utf8)!
print(jsonString)
回答by Dheeraj D
Answer for your question is below:
您的问题的答案如下：
Swift 2.1
斯威夫特 2.1
do {
if let postData : NSData = try NSJSONSerialization.dataWithJSONObject(dictDataToBeConverted, options: NSJSONWritingOptions.PrettyPrinted){
let json = NSString(data: postData, encoding: NSUTF8StringEncoding)! as String
print(json)}
}
catch {
print(error)
}
回答by StevenOjo
Here's an easy extension to do this:
这是一个简单的扩展来做到这一点：
https://gist.github.com/stevenojo/0cb8afcba721838b8dcb115b846727c3
https://gist.github.com/stevenojo/0cb8afcba721838b8dcb115b846727c3
extension Dictionary {
func jsonString() -> NSString? {
let jsonData = try? JSONSerialization.data(withJSONObject: self, options: [])
guard jsonData != nil else {return nil}
let jsonString = String(data: jsonData!, encoding: .utf8)
guard jsonString != nil else {return nil}
return jsonString! as NSString
}
}
回答by Swati Desai
private func convertDictToJson(dict : NSDictionary) -> NSDictionary?
{
var jsonDict : NSDictionary!
do {
let jsonData = try JSONSerialization.data(withJSONObject:dict, options:[])
let jsonDataString = String(data: jsonData, encoding: String.Encoding.utf8)!
print("Post Request Params : \(jsonDataString)")
jsonDict = [ParameterKey : jsonDataString]
return jsonDict
} catch {
print("JSON serialization failed: \(error)")
jsonDict = nil
}
return jsonDict
}
