サーバの JSON テキストから Objective-C のインスタンスを生成するライブラリ、SimpleRemoteObject を公開しました。 ref: http://qiita.com/items/049b9c4584769fe37896

file4.txt

[User fetchAsync:^(NSArray *allRemote, NSError *error) {
 if (error){
     //Do error handling
 }else{
     for (User* user in allRemote){
         NSLog(@"my name is:%@",user.name);
     }
 }
}];

User.h

#import <SimpleRemoteObject/SRSimpleRemoteObject.h>
@interface User : SRSimpleRemoteObject
@property(nonatomic,retain) NSString *name;
@property(nonatomic,retain) NSString *email;
@property(nonatomic) int age;
@end

User.m

#import "User.h"

@implementation Tag
+(NSString *)representUrl{
 return @"users.json"; // server path
}
+(NSString *)resultKey{
 return @"objects"; // key of target JSON object
}
@end

users.json

{
meta: {
 limit: 20,
 next: null,
 offset: 0,
 previous: null,
 total_count: 3
},
objects: [
 {
   id: 2,
   name: "Daniel",
   email: "daniel@example.com",
   age: 25
 },
 {
   id: 2,
   name: "Mario",
   email: "mario@example.com",
   age: 30
 },
 {
   id: 3,
   name: "Hal",
   email: "hal@example.com",
   age: 32
 }
]
}

YourAppDelegate.h

#import <SimpleRemoteObject/SRSimpleRemoteObject.h>

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
 [SRRemoteConfig defaultConfig].baseurl = SERVER_URL;

 // Override point for customization after application launch.
 return YES;
}