一、添加ASIHttpRequest

方法：http://www.jb51.cc/article/p-yvppbqaw-tm.html

二、添加SBJson

SBJson的开放源码在github上托管。

三、以上工作完成之后，下面就是敲代码了

（1）首先加入头文件

#import "ASIHTTPRequest.h"
#import "SBJson.h"

（2）Http请求

    NSURL *url = [NSURL URLWithString:@"http://......."];
    ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
    [request setDelegate:self];
    [request startAsynchronous];         //对应的同步请求[request startSynchronous];

（3）请求完成后，会调用requestFinished方法

-(void) requestFinished: (ASIHTTPRequest *) request {

	NSString *responseData = [request responseString];      //获得服务器response的数据
	//解析Json数据....
}

（4）Json数据处理

（a）处理一条记录

测试用的字符串是：responseData =@"{\"user\":{\"id\":21,\"name\":\"xxx\"}}";

SBJsonParser * parser = [[SBJsonParser alloc] init];  
    NSError * error = nil;  
    NSMutableDictionary *jsonDic = [parser objectWithString:responseString error:&error];
    
    NSLog(@"%@",[jsonDic objectForKey:@"user" ]);
    NSMutableDictionary * dicUserInfo = [jsonDic objectForKey:@"user"];
    NSLog(@"%@",[dicUserInfo objectForKey:@"id"]);
    NSLog(@"%@",[dicUserInfo objectForKey:@"name"]);

（b）处理多条记录

测试用的字符串是：

    SBJsonParser * parser = [[SBJsonParser alloc] init];  
    NSError * error = nil;  
    NSArray *memberList = [parser objectWithString:responseString error:&error];  
    
    for(NSDictionary *member in memberList)
    {
        NSLog(@"dibitsID = %d",[[member objectForKey:@"dibitsID"] integerValue]);
        NSLog(@"type = %d",[[member objectForKey:@"type"] integerValue]);
        NSLog(@"time = %@",[member objectForKey:@"updated"]);
        NSLog(@"\n");
    }