1 JSON基础
JSON全称是JavaScript Object Notation，它是一种轻量级的数据交换格式。JSON数据格式既适合人进行读写，也适合计算机本身解析和生成。早期，JSON是JavaScript语言的数据交换格式，后来发展成为一种与语言无关的数据交换格式。JSON在许多编程语言中使用，包括java、C、Objcetive-C、C++、C#、JavaScript、Perl、Python等。JSON提供了多种语言之间的交换数据的能力，因此，JSON是一种非常理想的数据结构。
服务器返回给客户端的数据，一般都是JSON格式或者XML格式（文件下载除外）
资料网站：http://www.w3cschool.cc/
JSON主要有两种数据结构。
- 由key－value对组成的数据结构，类似于Objective－C中的字典NSDictionary，如：{"name" :"jack", "age" :10}
- 有序集合，类似于Objective－C中的NSArray，如：
[ { "firstName":"John" , "lastName":"Doe" }, { "firstName":"Anna" , "lastName":"Smith" }, { "firstName":"Peter" , "lastName":"Jones" } ]
JSON—OC对照表
JSON－OC转换
2 JSON解析方案
JSON的常见解析方案有4种：
苹果原生（自带）：NSJSONSerialization（性能最好）
第三方框架：JSONKit、SBJson、TouchJSON（性能从左到右，越差）
提示：JSON本质上是一个特殊格式的字符串，注意不是NSString，JSON的解析是一个非常繁琐的工作！
解析
1 使用NSJSONSerialization解析
http://api.36wu.com/Weather/GetWeather这个网址获取天气信息需要申请key值，试用期小于1天。
-(void)JSONSerializationParse{
NSURL *url = [NSURL URLWithString:@"http://api.36wu.com/Weather/GetWeather"];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
request.HTTPMethod = @"POST";
//district表示区域id，authkey申请的试用值，只允许试用一天。所以过了2016/9/9就获取不到数据了，key自己去http://www.36wu.com申请试用。
request.HTTPBody = [@"district=101010100&format=json&authkey=b0aa5ef944514793812734e0b36e5740" dataUsingEncoding:NSUTF8StringEncoding];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * response, NSData * data, NSError * connectionError) {
NSLog(@"conncetionError:%@",connectionError);
NSLog(@"string:%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
NSLog(@"dictionary:%@",dictionary);
NSDictionary *dataDictionary = dictionary[@"data"];
NSLog(@"weather=%@,refreshTime=%@",dataDictionary[@"weather"],dataDictionary[@"refreshTime"]);
}];
}打印如下：
2016-09-09 15:59:01.500 JSON解析[942:983924] conncetionError:(null)
2016-09-09 15:59:01.502 JSON解析[942:983924] string:{"data":{"areaid":101010100,"prov":"北京","city":"北京","district":"北京","dateTime":"2016年9月9日","temp":"31℃","minTemp":"18℃","maxTemp":"31℃","weather":"晴","windDirection":"西风","windForce":"2级","humidity":"27%","img_1":"1","img_2":"4","refreshTime":"15:54"},"message":"OK","status":200}
2016-09-09 15:59:01.503 JSON解析[942:983924] dictionary:{
data = {
areaid = 101010100;
city = "\U5317\U4eac";
dateTime = "2016\U5e749\U67089\U65e5";
district = "\U5317\U4eac";
humidity = "27%";
"img_1" = 1;
"img_2" = 4;
maxTemp = "31\U2103";
minTemp = "18\U2103";
prov = "\U5317\U4eac";
refreshTime = "15:54";
temp = "31\U2103";
weather = "\U6674";
windDirection = "\U897f\U98ce";
windForce = "2\U7ea7";
};
message = OK;
status = 200;
}
2016-09-09 15:59:01.508 JSON解析[942:983924] weather=晴,refreshTime=15:542 使用JSONKit解析
需要向工程中导入JSONKit.h和JSONKit.m文件。使用处需要引头文件
#import "JSONKit.h"
由于我导入的这个版本不支持ARC，所以需要对JSONKit.m文件设置禁止ARC
-(void)JSONKitParse{
NSURL *url = [NSURL URLWithString:@"http://api.36wu.com/Train/GetTicketInquiry"];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
request.HTTPMethod = @"POST";
//查询火车票接口
request.HTTPBody = [@"startStation=北京&arriveStation=上海&date=2016-10-01&authkey=b0aa5ef944514793812734e0b36e5740" dataUsingEncoding:NSUTF8StringEncoding];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * response, NSData * data, NSError * connectionError) {
NSLog(@"conncetionError:%@",connectionError);
NSLog(@"string:%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
//使用JSONkit方法
NSDictionary *dictionary = [data objectFromJSONData];
NSLog(@"dictionary:%@",dictionary);
NSArray *dataAry = dictionary[@"data"];
NSLog(@"dataAry count=%lu",(unsigned long)dataAry.count);
}];
}
由于数据太多就不全贴出来了。
//只是打印的string中的一部分
{"train_no":"240000G1010C","train_code":"G101","start_station":"北京南","end_station":"上海虹桥","from_station":"北京南","to_station":"上海虹桥","start_time":"06:44","arrive_time":"12:38","day_difference":"0","lishi":"05:54","from_station_no":"01","to_station_no":"11","gg_num":"--","gr_num":"--","qt_num":"--","rw_num":"--","rz_num":"--","tz_num":"--","wz_num":"--","yb_num":"--","yw_num":"--","yz_num":"--","ze_num":"522","zy_num":"47","swz_num":"21"}
//这是dictionary中的一部分
{
"arrive_time" = "12:38";
"day_difference" = 0;
"end_station" = "\U4e0a\U6d77\U8679\U6865";
"from_station" = "\U5317\U4eac\U5357";
"from_station_no" = 01;
"gg_num" = "--";
"gr_num" = "--";
lishi = "05:54";
"qt_num" = "--";
"rw_num" = "--";
"rz_num" = "--";
"start_station" = "\U5317\U4eac\U5357";
"start_time" = "06:44";
"swz_num" = 21;
"to_station" = "\U4e0a\U6d77\U8679\U6865";
"to_station_no" = 11;
"train_code" = G101;
"train_no" = 240000G1010C;
"tz_num" = "--";
"wz_num" = "--";
"yb_num" = "--";
"yw_num" = "--";
"yz_num" = "--";
"ze_num" = 522;
"zy_num" = 47;
}3 使用SBJson解析方法
需要导入SBJson.h文件
#import "SBJson.h"
-(void)SBJsonParse{
NSURL *url = [NSURL URLWithString:@"http://api.36wu.com/Translate/GetTranslate"];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
request.HTTPMethod = @"POST";
//翻译，不过服务下限了，翻译不出来。不过可以看一下SBJson解析。
request.HTTPBody = [@"q=今天天气很好&output=zh_en&format=json&authkey=b0aa5ef944514793812734e0b36e5740" dataUsingEncoding:NSUTF8StringEncoding];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * response, NSData * data, NSError * connectionError) {
NSLog(@"conncetionError:%@",connectionError);
NSLog(@"string:%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
//使用SBJson方法解析
SBJsonParser *sbJsonParse = [[SBJsonParser alloc] init];
NSDictionary *dictionary = [sbJsonParse objectWithData:data];
NSLog(@"dictionary:%@",dictionary);
}];
}过期了，没能正确翻译。
2016-09-09 17:12:52.218 JSON解析[985:995210] conncetionError:(null)
2016-09-09 17:12:52.220 JSON解析[985:995210] string:{"status":200,"message":"OK","data":[{"dst":"旧服务已下线，请迁移至 http://api.fanyi.baidu.com","src":"The previous service has been closed, please visit http://api.fanyi.baidu.com to apply for new service."}]}
2016-09-09 17:12:52.223 JSON解析[985:995210] dictionary:{
data = (
{
dst = "\U65e7\U670d\U52a1\U5df2\U4e0b\U7ebf\Uff0c\U8bf7\U8fc1\U79fb\U81f3 http://api.fanyi.baidu.com";
src = "The previous service has been closed, please visit http://api.fanyi.baidu.com to apply for new service.";
}
);
message = OK;
status = 200;
}4 使用TouchJson解析
解析需要引入头文件
#import "CJSONDeserializer.h"
转换某对象到JSON数据——即生成，序列化操作需要引入文件：
#import "CJSONDataserializer.h"
-(void)TouchJsonParse{
NSURL *url = [NSURL URLWithString:@"http://api.36wu.com/Bus/GetLineInfo"];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
request.HTTPMethod = @"POST";
//公交查询 一天就过期了这个key值
request.HTTPBody = [@"city=北京&line=21&format=json&authkey=b0aa5ef944514793812734e0b36e5740" dataUsingEncoding:NSUTF8StringEncoding];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * response, NSData * data, NSError * connectionError) {
NSLog(@"conncetionError:%@",connectionError);
NSLog(@"string:%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
//使用TouchJson解析
NSDictionary *dictionary = [[CJSONDeserializer deserializer] deserialize:data error:nil];
NSLog(@"dictionary:%@",dictionary);
}];
}该查询数据很长，就不全贴出来了。
{"name":"21路(北京西站-安华桥北)","info":"北京西站北广场5:00-23:00|安华桥北5:00-23:00 ;10公里以内票价2元，每增加5公里以内加价1元，最高票价4元。持卡乘车普通卡5折、学生卡2.5折优惠。","stats":"北京西站;北京世纪坛医院;皇亭子;军事博物馆;木樨地西;木樨地北;西城桥北5:00-23:00 ;10公里以内票价2元，每增加5公里以内加价1元，最高票价4元。持卡乘车普通卡5折、学生卡2.5折优惠。","stats":"北京西站;北京世纪坛医院;皇亭子;军事博物馆;木樨地西;木樨地北;西城\344\270三里河;三里河东口;二七剧场路北口;儿童医院路口西;月坛体育场;阜成门南;阜成门北;西直门南;索家坟;文慧桥北;明光桥北;蓟门桥;蓟门桥北;塔院小区南门;牡丹园西;牡丹园东;健德门桥西;健德门桥桥北5:00-23:00 ;10公里以内票价2元，每增加5公里以内加价1元，最高票价4元。持卡乘车普通卡5折、学生卡2.5折优惠。","stats":"北京西站;北京世纪坛医院;皇亭子;军事博物馆;木樨地西;木樨地北;西城\344\270三里河;三里河东口;二七剧场路北口;儿童医院路口西;月坛体育场;阜成门南;阜成门北;西直门南;索家坟;文慧桥北;明光桥北;蓟门桥;蓟门桥北;塔院小区南门;牡丹园西;牡丹园东;健德门桥西;健德门桥\344东;地铁北土城站;安贞西里;安华桥北"}
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作者：VNanyesheshou 发表于2016/9/9 21:10:11 原文链接
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