将JSON转化为NSArray或者NSDictionary

1    获得JSON文件的路径（以project.json文件为例）

        NSString *path=[[NSBundle
mainBundle]pathForResource:@"project"
ofType:@"json"];

2  加载JSON文件        

        NSData *data=[NSData
dataWithContentsOfFile:path];

3  将JSON转化为NSArray或者NSDictionary

        NSDictionary *dict

[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];

        NSArray *Array=[NSJSONSerialization
JSONObjectWithData:data
options:NSJSONReadingMutableContainers
error:nil];

此处options 选项有三：     

    NSJSONReadingMutableContainers 

     
Specifies that arrays and dictionaries are created as mutable objects.    //  创建可变的数组或字典 接收

    NSJSONReadingMutableLeaves 

     
Specifies that leaf strings in the JSON object graph are created as instances of NSMutableString.   // 指定在JSON对象可变字符串被创建为  
     NSMutableString的实例

    NSJSONReadingAllowFragments 

     
Specifies that the parser should allow top-level objects that are not an instance of NSArray or NSDictionary   //  指定解析器应该允许不属于的NSArray或NSDictionary中的实例顶层对象