ios学习笔记（三）-----json数据的解析

说一下 ios中关于 json 数据解析的 总体思想：   由于ios中不像java中 可以将json 和 实体类相互转换（其实 可以的，网上有人实现，但是比较麻烦，而且不能适用所有的业务逻辑），暂且不管它，ios中解析json的总体思想是：将json看做 字典 处理，当然对于复杂的json，可以看做，外部是个字典，内部也是一个字典，嵌套使用，解析的时候，可以由外到内，一层层的剥开。比如外层的 一个key 对应的一个字典，那么 objectforkey：（key） 得到便是一个字典的对象，那么 可以对该对象继续 objectforkey：（key） 这样就又剥开了一层，以此内推。

按照的上文的做法，如图：

代码如下：

ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@property (retain, nonatomic) IBOutlet UITextView *txtView;

- (IBAction)btnPressTouchJson:(id)sender;
- (IBAction)btnPressSBJson:(id)sender;
- (IBAction)btnPressIOS5Json:(id)sender;
- (IBAction)btnPressJsonKit:(id)sender;



@end

ViewController.m

#import "ViewController.h"
#import "CJSONDeserializer.h"
#import "SBJson.h"
#import "JSONKit.h"
@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
//使用TouchJson来解析北京的天气
- (IBAction)btnPressTouchJson:(id)sender {
    //获取API接口
    NSURL *url = [NSURL URLWithString:@"http://m.weather.com.cn/data/101010100.html"];
    //定义一个NSError对象，用于捕获错误信息
    NSError *error;
    NSString *jsonString = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];
    NSLog(@"jsonString--->%@",jsonString);
    //将解析得到的内容存放字典中，编码格式为UTF8，防止取值的时候发生乱码
    NSDictionary *rootDic = [[CJSONDeserializer deserializer] deserialize:[jsonString dataUsingEncoding:NSUTF8StringEncoding] error:&error];
    //因为返回的Json文件有两层，去第二层内容放到字典中去
    NSDictionary *weatherInfo = [rootDic objectForKey:@"weatherinfo"];
    NSLog(@"weatherInfo--->%@",weatherInfo);
    //取值打印
    _txtView.text = [NSString stringWithFormat:@"TouchJson解析--------》今天是 %@  %@  %@  的天气状况是：%@  %@ ",[weatherInfo objectForKey:@"date_y"],[weatherInfo objectForKey:@"week"],[weatherInfo objectForKey:@"city"], [weatherInfo objectForKey:@"weather1"], [weatherInfo objectForKey:@"temp1"]];
    
}

//使用SBJson解析南阳的天气
- (IBAction)btnPressSBJson:(id)sender {
    NSURL *url = [NSURL URLWithString:@"http://m.weather.com.cn/data/101180701.html"];
    NSError *error = nil;
    NSString *jsonString = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];
    SBJsonParser *parser = [[SBJsonParser alloc] init];
    
    NSDictionary *rootDic = [parser objectWithString:jsonString error:&error];
    NSDictionary *weatherInfo = [rootDic objectForKey:@"weatherinfo"];
    _txtView.text = [NSString stringWithFormat:@"SBJson解析--------》今天是 %@  %@  %@  的天气状况是：%@  %@ ",[weatherInfo objectForKey:@"date_y"],[weatherInfo objectForKey:@"week"],[weatherInfo objectForKey:@"city"], [weatherInfo objectForKey:@"weather1"], [weatherInfo objectForKey:@"temp1"]];
}

//使用ios5中自带的方法解析
- (IBAction)btnPressIOS5Json:(id)sender {
    
    NSError *error;
    //加载一个NSURL对象
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://m.weather.com.cn/data/101180601.html"]];
    //将请求的url数据放到NSData对象中
    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 *weatherDic = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingMutableLeaves error:&error];
    NSDictionary *weatherInfo = [weatherDic objectForKey:@"weatherinfo"];
    _txtView.text = [NSString stringWithFormat:@"IOS5自带解析--------》今天是 %@  %@  %@  的天气状况是：%@  %@ ",[weatherInfo objectForKey:@"date_y"],[weatherInfo objectForKey:@"week"],[weatherInfo objectForKey:@"city"], [weatherInfo objectForKey:@"weather1"], [weatherInfo objectForKey:@"temp1"]];
    NSLog(@"weatherInfo字典里面的内容为--》%@", weatherDic );
}

//使用JsonKit解析
- (IBAction)btnPressJsonKit:(id)sender {
    
    NSURL *url = [NSURL URLWithString:@"http://m.weather.com.cn/data/101180701.html"];
    NSError *error = nil;
    NSString *jsonString = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];
    NSDictionary *weatherDic=[jsonString objectFromJSONStringWithParseOptions:JKParseOptionLooseUnicode];
    NSDictionary *weatherInfo=[weatherDic objectForKey:@"weatherinfo"];
    _txtView.text = [NSString stringWithFormat:@"JsonKit解析--------》今天是 %@  %@  %@  的天气状况是：%@  %@ ",[weatherInfo objectForKey:@"date_y"],[weatherInfo objectForKey:@"week"],[weatherInfo objectForKey:@"city"], [weatherInfo objectForKey:@"weather1"], [weatherInfo objectForKey:@"temp1"]];
    NSLog(@"weatherInfo字典里面的内容为--》%@", weatherDic );

}

@end

完整的项目代码下载地址：http://download.csdn.net/detail/abc13939746593/5226247

SBJson   库的  下载地址：http://download.csdn.net/detail/abc13939746593/5226267

JsonKit  库的  下载地址：http://download.csdn.net/detail/abc13939746593/5226265

TouchJson 库的  下载地址：http://download.csdn.net/detail/abc13939746593/5226258

参考下面的文章做的：

http://blog.csdn.net/enuola/article/details/7903632

不过这位大神的文章写的有点乱了，给的链接都是同一个文件