iOS的JSON解析返回null

我解析一個JSON看起來像這樣：iOS的JSON解析返回null

[ 
    { 
    "Country of Build":"Belgium", 
    "Shipbuilder":" Boelwerf", 
    "Hull #":" 1487", 
    "Ship Name":" Methania", 
    "Shipowner":" Distrigas", 
    "Operator":" Exmar", 
    "Delivery":"Oct-78", 
    "Flag":" Belgium", 
    "Class":" LR", 
    "Power Plant":" Steam", 
    "HP":" 45,000", 
    "Speed": 19.0, 
    "Cargo System":" GT NO 85", 
    "# of Tanks": 5, 
    "Capacity ":" 131,235", 
    "Price": 
    }, 
    { 
    "Country of Build":"China", 
    "Shipbuilder":" Cosco Dalian", 
    "Hull #":" ", 
    "Ship Name":" ", 
    "Shipowner":" CNOOC Energy", 
    "Operator":" ", 
    "Delivery":" 1Q15", 
    "Flag":" ", 
    "Class":" AB/CC", 
    "Power Plant":" DFDE", 
    "HP":" ", 
    "Speed": , 
    "Cargo System":" GT NO 96", 
    "# of Tanks": 4, 
    "Capacity ":" 28,000", 
    "Price":81 
    }, ---8000 more lines--- }]

我有，我想分析的對象到自定義對象，它看起來是這樣的： .H

@interface LNGVessel : NSObject 

@property NSString *countryOfBuild; 
@property NSString *shipBuilder; 
@property NSString *hull; 
@property NSString *shipName; 
@property NSString *shipOwner; 
@property NSString *shipOperator; 
@property NSString *delivery; 
@property NSString *flag; 
@property NSString *shipClass; 
@property NSString *powerPlant; 
@property NSString *hp; 
@property NSString *speed; 
@property NSString *cargoSystem; 
@property NSString *numOfTanks; 
@property NSString *capacity; 
@property NSString *price; 

-(id)initWithDict:(NSDictionary*)dictionary; 

@end

像這樣

-(id)initWithDict:(NSDictionary *)dictionary{ 
self = [super init]; 
if(self) 
{ 
    self.countryOfBuild = [dictionary objectForKey:@"Country of Build"]; 
    self.shipBuilder = [dictionary objectForKey:@"Shipbuilder"]; 
    self.hull = [dictionary objectForKey:@"Hull #"]; 
    self.shipName = [dictionary objectForKey:@"Ship Name"]; 
    self.shipOwner = [dictionary objectForKey:@"Shipowner"]; 
    self.shipOperator = [dictionary objectForKey:@"Operator"]; 
    self.delivery = [dictionary objectForKey:@"Delivery"]; 
    self.flag = [dictionary objectForKey:@"Flag"]; 
    self.shipClass = [dictionary objectForKey:@"Class"]; 
    self.powerPlant = [dictionary objectForKey:@"Power Plant"]; 
    self.hp = [dictionary objectForKey:@"HP"]; 
    self.speed = [dictionary objectForKey:@"Speed"]; 
    self.cargoSystem = [dictionary objectForKey:@"Cargo System"]; 
    self.numOfTanks = [dictionary objectForKey:@"# of Tanks"]; 
    self.capacity = [dictionary objectForKey:@"Capacity"]; 
    self.price = [dictionary objectForKey:@"Price"]; 

} 
return self; 
}

一個.M現在，我有一個本地上傳.json文件，約8000線，450是h物體。我分析他們在UIMutableArray類別的數組，它看起來像這樣：

//.h 
@interface NSMutableArray (LNGVessels) 
+(NSMutableArray*)allVessels; 

@end 

//.m 

    @implementation NSMutableArray (LNGVessels) 

+(NSMutableArray*)allVessels{ 
    NSMutableArray *array; 

    NSString* pathToFile = [[NSBundle mainBundle] pathForResource:@"Vessels" ofType: @"json"]; 

    NSData *data = [[NSData alloc]initWithContentsOfFile:pathToFile]; 

    id JSONArray = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]; 


    NSEnumerator *enumerator = [JSONArray objectEnumerator]; 
    NSDictionary* item; 
    while (item = (NSDictionary*)[enumerator nextObject]) { 

     LNGVessel *vessel = [[LNGVessel alloc]initWithDict:item]; 
     [array addObject:vessel]; 
    } 
    return array; 
} 
@end

的問題？這不起作用，它總是返回null。我已經登錄NSData的對象，它返回的所有內容的JSON（十六進制）

我認爲這可能是JSON的錯，所以我檢查http://jsonlint.com/並粘貼了整個事情。我得到了一個錯誤

Parse error on line 18: 
...  "Price":  }, {  "Co 
----------------------^ 
Expecting 'STRING', 'NUMBER', 'NULL', 'TRUE', 'FALSE', '{', '['

這表明我需要解決這個問題。但是，我仍然認爲我的代碼只會爲該參數插入nil。

哦，我意識到JSONSerilaziation得到了一個錯誤參數。它記錄

Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (Invalid value around character 376.) UserInfo=0x170463380 {NSDebugDescription=Invalid value around character 376.}

來源

2013-11-28 Oscar Apeland

你的JSON應該是

{ 
... 
"Price":null 
... 
}

根據蘋果文檔：

JSONObjectWithData:options:error:

error If an error occurs, upon return contains an NSError object that describes the problem.

Return Value A Foundation object from the JSON data in data, or nil if an error occurs.

設置error參數nil可能不會在這樣的時候有所幫助。

來源

2013-11-28 10:00:23

它的JSON文檔錯誤？是否有任何工具可以將空對象插入到空的參數中，這樣做可能會產生8000條線會是一種痛苦。 –

我想它會更好，你要確保這是問題所在，首先用更小和完全有效的JSON對象測試你的代碼，如果它確定，那麼銳化你的正則表達式技巧:)你可以查找無效模式並用正則表達式替換它們你懂。 –

我將源代碼粘貼到EXCEL中，將其作爲CSV導出，並將解析後的CSV導出爲JSON，在此過程中，null插入而不是未插入。現在代碼有效，JSON是罪人。 –

我會做這樣的：

NSArray *array = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]; 
for (NSDictionary *dict in array) { 
    LNGVessel *vessel = [[LNGVessel alloc]initWithDict:dict]; 
    .... 
}

來源

2013-11-28 09:55:21 thorb65

我做了，但其他一些問題，我來了，建議使用像這樣的快速枚舉，所以我認爲這是更好的。 –

正如你已經注意到了，你的JSON數據是無效的。

id JSONArray = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];

只是返回nil。（它不會省略或跳過無效條目。）

而且您還忘記了alloc + init的NSMutableArray *array。

來源

2013-11-28 09:56:40

iOS的JSON解析返回null

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