JSon解析

1.使用JSONKit的解析方法：（需导入包：#import "JSONKit/JSONKit.h"）   

- (IBAction)btnPressJsonKit:(id)sender {
    
    //如果json是“单层”的，即value都是字符串、数字，可以使用objectFromJSONString
    NSString *json1 = @"{"a":123, "b":"abc"}";
    NSLog(@"json1:%@",json1);
    NSDictionary *data1 = [json1 objectFromJSONString];
    NSLog(@"json1.a:%@",[data1 objectForKey:@"a"]);
    NSLog(@"json1.b:%@",[data1 objectForKey:@"b"]);
    [json1 release];
    
    //如果json有嵌套，即value里有array、object，如果再使用objectFromJSONString，程序可能会报错（测试结果表明：使用由网络或得到的php/json_encode生成的json时会报错，但使用NSString定义的json字符串时，解析成功），最好使用objectFromJSONStringWithParseOptions：
    NSString *json2 = @"{"a":123, "b":"abc", "c":[456, "hello"], "d":{"name":"张三", "age":"32"}}";
    NSLog(@"json2:%@", json2);
    NSDictionary *data2 = [json2 objectFromJSONStringWithParseOptions:JKParseOptionLooseUnicode];
    NSLog(@"json2.c:%@", [data2 objectForKey:@"c"]);
    NSLog(@"json2.d:%@", [data2 objectForKey:@"d"]);
    [json2 release];
}




2.//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:@"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"]];
    
}

3.//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:@"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"]];
}

参照：http://www.cnblogs.com/jiangyuxuan/archive/2013/03/09/2950984.html