有需要的朋友可以参考一下

NSJSONSerialization（JSON序列化）

You use the NSJSONSerialization class to convert JSON to Foundation objects and convert Foundation objects to JSON.

你可以使用NSJSONSerialization 类把json和foundation对象相互转化。

An object that may be converted to JSON must have the following properties:

• The top level object is an NSArray or NSDictionary.

• All objects are instances of NSString, NSNumber, NSArray, NSDictionary, or NSNull.

• All dictionary keys are instances of NSString.

• Numbers are not NaN or infinity.

Other rules may apply. Calling isValidJSONObject: or attempting a conversion are the definitive ways to tell if a given object can be converted to JSON data.

其他的条件可能被应用，调用 isValidJSONOBject:或者尝试转换是最后的方法来分辨所给对象是否可以转换成JSON类型的数据。

简单的解析代码

//
//  ViewController.m
//  Jason
//
//  Created by Bc_Ltf on 15/3/26.
//  Copyright (c) 2015年 Bc_ltf. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setup];

}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

-(void)setup
{
    NSError *error;
    //加载一个NSURL对象
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://gc.ditu.aliyun.com/geocoding?a=%E8%8B%8F%E5%B7%9E%E5%B8%82"]];
    //将请求的url数据放到NSData对象中  <span style="font-size:14px;">本文原创，转载请注明出处：</span><span style="font-size:14px;">http://blog.csdn.net/zhenggaoxing/article/details/44649827</span>
    NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    //IOS5自带解析类NSJSONSerialization从response中解析出数据放到字典中
    NSDictionary *ali = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingMutableLeaves error:&error];
    //    NSDictionary *weatherInfo = [weatherDic objectForKey:@"weatherinfo"];

    NSLog(@"现在你可以看到Jason内容了：%@", ali );
}

@end