JSON即JavaScript Object Natation，它是一種輕量級(jí)的數(shù)據(jù)交換格式，非常適合于服務(wù)器與客戶端的交互。
關(guān)于iOS平臺(tái)上進(jìn)行JSON解析，因?yàn)锳pple退出了自帶的SDK：NSJSONSerialization，這是一個(gè)非常好用的JSON生成和解析工具。

NSJSONSerialization提供了JSON數(shù)據(jù)封包、JSON數(shù)據(jù)解析，NSJSONSerialization將JSON數(shù)據(jù)轉(zhuǎn)換為NSDictionary或NSArray解包方法，將NSDictionary、NSArray對(duì)象轉(zhuǎn)換為JSON數(shù)據(jù)（可以通過(guò)調(diào)用isValidJSONObject來(lái)判斷NSDictionary、NSArray對(duì)象是否可以轉(zhuǎn)換為JSON數(shù)據(jù)）封包。

NSJSONSerialization Class Reference

• JSON數(shù)據(jù)封包

NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"value1",@"key1",@"value2",@"key2",@"value3",@"key3", nil];  
   // isValidJSONObject判斷對(duì)象是否可以構(gòu)建成json對(duì)象  
   if ([NSJSONSerialization isValidJSONObject:dic]){  
       NSError *error;  
       // 創(chuàng)造一個(gè)json從Data, NSJSONWritingPrettyPrinted指定的JSON數(shù)據(jù)產(chǎn)的空白，使輸出更具可讀性。  
       NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&error];  
       NSString *json =[[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];  
       NSLog(@"json data:%@",json);  
   } 

• JSON數(shù)據(jù)解析

NSError *error;  
    //加載一個(gè)NSURL對(duì)象  
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://m.weather.com.cn/data/101120101.html"]];  
    //將請(qǐng)求的url數(shù)據(jù)放到NSData對(duì)象中  
    NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];  
    //IOS5自帶解析類NSJSONSerialization從response中解析出數(shù)據(jù)放到字典中  
    NSDictionary *weatherDic = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingMutableLeaves error:&error];  
    NSDictionary *weatherInfo = [weatherDic objectForKey:@"weatherinfo"];  
    NSString *text = [NSString stringWithFormat:@"今天是 %@  %@  %@  的天氣狀況是：%@  %@ ",[weatherInfo objectForKey:@"date_y"],[weatherInfo objectForKey:@"week"],[weatherInfo objectForKey:@"city"], [weatherInfo objectForKey:@"weather1"], [weatherInfo objectForKey:@"temp1"]];  
    NSLog(@"weatherInfo：%@", text );

NSJSONReadingOptions