iOS开发json解析之天气预报

简单的demo：

NSError *error;
    //1.    加载一个NSURL对象
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.weather.com.cn/data/cityinfo/101100101.html"]];
    //2.    将请求的url数据放到NSData对象中
    NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    //3.   iOS5自带解析类NSJSONSerialization从response中解析出数据放到字典中
    NSDictionary *weatherDic = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingMutableLeaves error:&error];
    //4.    weatherDic字典中存放的数据也是字典型，从它里面通过键值取值
    NSDictionary *weatherInfo = [weatherDic objectForKey:@"weatherinfo"];
    
    NSLog(@"今天%@的天气是%@ 最高温度是:%@ 最低温度是:%@",[weatherInfo objectForKey:@"city"],[weatherInfo objectForKey:@"weather"],[weatherInfo objectForKey:@"temp1"],[weatherInfo objectForKey:@"temp2"]);

整个过程就是发送请求→接受请求 病存到字典中，然后就是从字典中取数据了。