Question

我有dictionary我需要使用JSON string生成dictionary。有可能转换它吗？你能帮忙吗？

Answer 1

Apple在iOS 5.0和Mac OS X 10.7中添加了JSON解析器和序列化程序。请参阅NSJSONSerialization。

要从NSDictionary或NSArray生成JSON字符串，您不再需要导入任何第三方框架。

以下是如何操作：

NSError *error; 
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictionaryOrArrayToOutput 
                                                   options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
                                                     error:&error];

if (! jsonData) {
    NSLog(@"Got an error: %@", error);
} else {
    NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

Answer 2

以下是NSArray和NSDictionary的类别，使这非常容易。我添加了一个漂亮的打印选项（新行和标签，以便于阅读）。

@interface NSDictionary (BVJSONString)
-(NSString*) bv_jsonStringWithPrettyPrint:(BOOL) prettyPrint;
@end

@implementation NSDictionary (BVJSONString)

  -(NSString*) bv_jsonStringWithPrettyPrint:(BOOL) prettyPrint {
     NSError *error;
     NSData *jsonData = [NSJSONSerialization dataWithJSONObject:self
                                                   options:(NSJSONWritingOptions)    (prettyPrint ? NSJSONWritingPrettyPrinted : 0)
                                                     error:&error];

     if (! jsonData) {
        NSLog(@"%s: error: %@", __func__, error.localizedDescription);
        return @"{}";
     } else {
        return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
     } 
 }
@end

@interface NSArray (BVJSONString)
- (NSString *)bv_jsonStringWithPrettyPrint:(BOOL)prettyPrint;
@end

@implementation NSArray (BVJSONString)
-(NSString*) bv_jsonStringWithPrettyPrint:(BOOL) prettyPrint {
    NSError *error;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:self
                                                       options:(NSJSONWritingOptions) (prettyPrint ? NSJSONWritingPrettyPrinted : 0)
                                                         error:&error];

    if (! jsonData) {
        NSLog(@"%s: error: %@", __func__, error.localizedDescription);
        return @"[]";
    } else {
        return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
    }
}
@end

Answer 3

将NSDictionary转换为NSString：

NSError * err;
NSData * jsonData = [NSJSONSerialization dataWithJSONObject:myDictionary options:0 error:&err]; 
NSString * myString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

Answer 4

注意：此答案是在iOS 5发布之前给出的。

获取json-framework并执行此操作：

#import "SBJsonWriter.h"

...

SBJsonWriter *jsonWriter = [[SBJsonWriter alloc] init];

NSString *jsonString = [jsonWriter stringWithObject:myDictionary];  

[jsonWriter release];

myDictionary将是您的字典。

Answer 5

您也可以通过在调试器中输入以下内容来实时执行此操作

po [[NSString alloc] initWithData:[NSJSONSerialization dataWithJSONObject:yourDictionary options:1 error:nil] encoding:4];

Answer 6

您可以传递数组或字典。在这里，我正在使用NSMutableDictionary。

NSMutableDictionary *contentDictionary = [[NSMutableDictionary alloc]init];
[contentDictionary setValue:@"a" forKey:@"b"];
[contentDictionary setValue:@"c" forKey:@"d"];

要从NSDictionary或NSArray生成JSON字符串，您无需导入任何第三方框架。只需使用以下代码： -

NSError *error; 
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:contentDictionary // Here you can pass array or dictionary
                    options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
                    error:&error];
NSString *jsonString;
if (jsonData) {
    jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
    //This is your JSON String
    //NSUTF8StringEncoding encodes special characters using an escaping scheme
} else {
    NSLog(@"Got an error: %@", error);
    jsonString = @"";
}
NSLog(@"Your JSON String is %@", jsonString);

Answer 7

NSMutableDictionary *contentDictionary = [[NSMutableDictionary alloc]init];
        [contentDictionary setValue:@"a" forKey:@"b"];
        [contentDictionary setValue:@"c" forKey:@"d"];
        NSData *data = [NSJSONSerialization dataWithJSONObject:contentDictionary options:NSJSONWritingPrettyPrinted error:nil];
        NSString *jsonStr = [[NSString alloc] initWithData:data
                                                  encoding:NSUTF8StringEncoding];

Answer 8

在 Swift（版本2.0）：

class func jsonStringWithJSONObject(jsonObject: AnyObject) throws -> String? {
    let data: NSData? = try? NSJSONSerialization.dataWithJSONObject(jsonObject, options: NSJSONWritingOptions.PrettyPrinted)

    var jsonStr: String?
    if data != nil {
        jsonStr = String(data: data!, encoding: NSUTF8StringEncoding)
    }

    return jsonStr
}

Answer 9

现在不需要第三方课程ios 5引入了Nsjsonserialization

NSString *urlString=@"Your url";
NSString *urlUTF8 = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url=[[NSURL alloc]initWithString:urlUTF8];
NSURLRequest *request=[NSURLRequest requestWithURL:url];

NSURLResponse *response;

NSData *GETReply = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];

NSError *myError = nil;

NSDictionary *res = [NSJSONSerialization JSONObjectWithData:GETReply options:NSJSONReadingMutableLeaves|| NSJSONReadingMutableContainers error:&myError];

Nslog(@"%@",res);

此代码可用于获取jsondata。

Answer 10

至于ISO7，至少可以使用NSJSONSerialization轻松完成此操作。

Answer 11

在Swift中，我创建了以下辅助函数：

|-------------|
| header      |
|-------------|
|             |
| main        |
|             |
|             |
|-------------|
| footer      |
|-------------|

Answer 12

这是 Swift 4 版本

extension NSDictionary{

func toString() throws -> String? {
    do {
        let data = try JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
        return String(data: data, encoding: .utf8)
    }
    catch (let error){
        throw error
    }
}

}

用法示例

do{
    let jsonString = try dic.toString()
    }
    catch( let error){
        print(error.localizedDescription)
    }

或者，如果您确定它是有效的字典，那么您可以使用

let jsonString = try? dic.toString()

Answer 13

这将在swift4和swift5中工作。

let dataDict = "the dictionary you want to convert in jsonString" 

let jsonData = try! JSONSerialization.data(withJSONObject: dataDict, options: JSONSerialization.WritingOptions.prettyPrinted)

let jsonString = NSString(data: jsonData, encoding: String.Encoding.utf8.rawValue)! as String

print(jsonString)

Answer 14

<div ng-repeat="fruit in fruits">
    <input type="checkbox" name="{{fruit.name}} ng-model="fruit.value" 
         ng-click="isChecked(fruit)" required>{{fruit.name}}
</div>
<input type="hidden" ng-model="selectedFruits">

这个非常接近原始的Objective-C打印样式

在iOS中从NSDictionary生成JSON字符串

14 个答案: