通过大众点评平台开发来简单了解一下，oc的网络编程和数据解析（json）
首先我们需要到大大众点评开发者平台申请一个key。http://developer.dianping.com/app/tech/api这个网站有api文档。
本文没有使用第三方库，网络其请求使用NSURLConnection类，json数据解析使用NSJSONSerialization。这个例子是根据条件获取商户信息。
1.定义常量
#define kSearchResto @"v1/business/find_businesses"
#define kDPDomain @"http://api.dianping.com/"
#define kDPAppKey @"。。。"
#define kDPAppSecret @"。。。"
#define kWFRequestimeOutInterval 60.0
#define kHttpMethodGET @"GET"
#define kHttpMethodPOST @"POST"
2.创建数据类，包含商户信息
//
// WFBusiness.h
// WFSearch
//
// Created by ForrestWoo on 14-9-5.
// Copyright (c) 2014年 ForrestWoo. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "WFRootModel.h"
@interface WFBusiness : WFRootModel
@PRoperty (nonatomic, assign) int business_id;
@property (nonatomic, strong) NSString *name;
@property (nonatomic, strong) NSString *branch_name;
@property (nonatomic, strong) NSString *address;
@property (nonatomic, strong) NSString *telephone;
@property (nonatomic, strong) NSString *city;
//星级图片链接。
@property (nonatomic, strong) NSString *rating_img_url;
@property (nonatomic, strong) NSString *rating_s_img_url;
@property (nonatomic, strong) NSArray *regions;
@property (nonatomic, strong) NSArray *categories;
//经纬度信息
@property (nonatomic, assign) float latitude;
@property (nonatomic, assign) float longitude;
@property (nonatomic, assign) float avg_rating;
@property (nonatomic, assign) float product_score;
@property (nonatomic, assign) float decoration_score;
@property (nonatomic, assign) float service_score;
//评价 分五种。1:一般，2:尚可，3:好，4:很好，5:非常好
@property (nonatomic, assign) int product_grade;
@property (nonatomic, assign) int decoration_grade;
@property (nonatomic, assign) int service_grade;
//人均消费。
@property (nonatomic, assign) int avg_price;
//点评。
@property (nonatomic, assign) int review_count;
@property (nonatomic, strong) NSArray *review_list_url;
@property (nonatomic, assign) int distance;
@property (nonatomic, strong) NSString *business_url;
//图片
@property (nonatomic, strong) NSString *photo_url;
@property (nonatomic, strong) NSString *s_photo_url;
@property (nonatomic, assign) int photo_count;
@property (nonatomic, strong) NSArray *photo_list_url;
//优惠券。
@property (nonatomic, assign) int has_coupon;
@property (nonatomic, assign) int coupon_id;
@property (nonatomic, strong) NSString *coupon_description;
@property (nonatomic, strong) NSString *coupon_url;
//团购信息。
@property (nonatomic, assign) int has_deal;
@property (nonatomic, assign) int deal_count;
@property (nonatomic, strong) NSArray *deals;
@property (nonatomic, strong) NSString *deals_id;
@property (nonatomic, strong) NSString *deals_description;
@property (nonatomic, strong) NSString *deals_url;
@property (nonatomic, assign) int has_online_reservation;
@property (nonatomic, strong) NSString *online_reservation_url;
- (id)initWithJson:(NSDictionary *)jsonData;
@end
这里的属性名字并不是随便定义的，而是根据服务器端返回的字段名称定义的，它与返回的名称是一致的，目的是方便以后通过反射对类的属性赋值，这样我们不需要一一赋值，详情请继续
3.WFRootModel
#import <Foundation/Foundation.h>
//根类，定义一些通用的属性和消息
@interface WFRootModel : NSObject
//获取类的属性名称，以通过反射对对象的属性赋值。
- (NSArray *)PropertyKeys;
@end
#import "WFRootModel.h"
#import <objc/runtime.h>
@implementation WFRootModel
- (NSArray *)PropertyKeys
{
unsigned int outCount,i;
objc_property_t *pp = class_copyPropertyList([self class], &outCount);
NSMutableArray *keys = [[NSMutableArray alloc] initWithCapacity:0];
for (i = 0; i < outCount; i++)
{
objc_property_t property = pp[i];
NSString *propertyName = [[NSString alloc] initWithCString:property_getName(property) encoding:NSUTF8StringEncoding];
[keys addObject:propertyName];
}
return keys;
}
@end
此类赋予了它的子类一个重要行为，它只包含一个消息［- (NSArray *)PropertyKeys］，它的作用是子类能够获取自己包含的所有属性。反射中会使用这些属性。
4.创建请求url
大众点评请求使用SHA加密。
［1］SHA加密类SHA1,需要引入
CommonDigest.h
@interface SHA1 : NSObject
+ (NSString *)getSHAString:(NSData *)aStringbytes;
@end
#import <CommonCrypto/CommonDigest.h>
#import "SHA1.h"
@implementation SHA1
+ (NSString *)getSHAString:(NSData *)aStringbytes
{
unsigned char digest[CC_SHA1_DIGEST_LENGTH];
if (CC_SHA1([aStringbytes bytes], [aStringbytes length], digest))
{
NSMutableString *digestString = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH];
for (int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++)
{
unsigned char aChar = digest[i];
[digestString appendFormat:@"%02x",aChar];
}
return digestString;
}
else
{
return nil;
}
}
@end
由于我对加密了解很少，所以就不做介绍了，只给出一个方法，供大家参考。
［2］返回根url，因为根url会常用到，我们就将它封装起来，以便后用
- (NSString *)getRootURL
{
return kDPDomain;
}
［3］返回合法的url
- (NSString *)serializeURL:(NSString *)aBaseURL params:(NSDictionary *)aParams
{
NSURL* parsedURL = [NSURL URLWithString:[aBaseURL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSMutableDictionary *paramsDic = [NSMutableDictionary dictionaryWithDictionary:[self parseQueryString:[parsedURL query]]];
if (aParams) {
[paramsDic setValuesForKeysWithDictionary:aParams];
}
NSMutableString *signString = [NSMutableString stringWithString:kDPAppKey];
NSMutableString *paramsString = [NSMutableString stringWithFormat:@"appkey=%@", kDPAppKey];
NSArray *sortedKeys = [[paramsDic allKeys] sortedArrayUsingSelector: @selector(compare:)];
for (NSString *key in sortedKeys) {
[signString appendFormat:@"%@%@", key, [paramsDic objectForKey:key]];
[paramsString appendFormat:@"&%@=%@", key, [paramsDic objectForKey:key]];
}
NSString *str = kDPAppSecret;
[signString appendString:str];
NSData *stringBytes = [signString dataUsingEncoding: NSUTF8StringEncoding];
NSString *digestString = [SHA1 getSHAString:stringBytes];
if (digestString)
{
[paramsString appendFormat:@"&sign=%@", [digestString uppercaseString]];
NSLog(@"...%@...", [NSString stringWithFormat:@"%@://%@%@?%@", [parsedURL scheme], [parsedURL host], [parsedURL path], [paramsString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]);
return [NSString stringWithFormat:@"%@://%@%@?%@", [parsedURL scheme], [parsedURL host], [parsedURL path], [paramsString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}
else
{
return nil;
}
}
5.创建网络连接，发送请求
使用NSURLConnection来完成网络连接
- (void)createConnectionWithUrl:(NSString *)urlString params:(NSDictionary *)aParams delegate:(id<WFRequestDelegate>)aDelegate
{
NSString *urlStr = [self serializeURL:[self generateFullURL:urlString] params:aParams];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:urlStr] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:kWFRequestimeOutInterval];
[request setHTTPMethod:kHttpMethodGET];
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
self.delegate = aDelegate;
// [[[self class] sharedInstance] setConnections:conn];
}
6.返回结果以及数据解析
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
_responseData = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[_responseData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSError *error = nil;
id result= [NSJSONSerialization JSONObjectWithData:_responseData options:NSJSONReadingAllowFragments error:&error];
if (!result)
{
NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:error,@"error", nil];
NSError *err = [NSError errorWithDomain:@"domain is error" code:-1 userInfo:userInfo];
if ([self.delegate respondsToSelector:@selector(request:didfailWithError:)])
{
[self.delegate request:self didfailWithError:err];
}
}
else
{
NSString *status = 0;
if ([result isKindOfClass:[NSDictionary class]])
{
status = [result objectForKey:@"status"];
}
if ([status isEqualToString:@"OK"])
{
if ([self.delegate respondsToSelector:@selector(request:didfinishloadingWithResult:)])
{
[self.delegate request:self didfinishloadingWithResult:result == nil ?
_responseData : result];
}
}
else
{
if ([status isEqualToString:@"ERROR"])
{
//TODO:错误处理代码。
}
}
}
// NSString *str = [[NSString alloc] initWithData:_responseData encoding:NSUTF8StringEncoding];
// NSLog(@"_responseData:%@", str);
// [self clearData];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"ERROR!%@", error.description);
}
返回的数据存储在一个WFFindBusinessesResult的实例中。
//super class for result.
@interface WFUrlResult : NSObject
@property (nonatomic, strong) NSString *status;
@property (nonatomic, assign) NSInteger total_count;
@property (nonatomic, assign) NSInteger count;
- (id)initWithJson:(NSDictionary *)jsonData;
@end
@interface WFFindBusinessesResult : WFUrlResult
@property (nonatomic, strong) NSArray *businesses;
@end
对对象赋值非常简单
@implementation WFFindBusinessesResult
- (id)initWithJson:(NSDictionary *)jsonData
{
self.status = [jsonData objectForKey:@"status"];
self.count = [[jsonData objectForKey:@"count"] integerValue];
self.total_count = [[jsonData objectForKey:@"total_count"] integerValue];
NSArray *arr = nil;
NSMutableArray *businessArr = [[NSMutableArray alloc] initWithCapacity:0];
if ([jsonData isKindOfClass:[NSDictionary class]])
{
arr = [jsonData objectForKey:@"businesses"];
//赋值,通过反射赋值，根本不需要一一对字段赋值。
for (id obj in arr)
{
WFBusiness *bus = [[WFBusiness alloc] init];
NSArray *propertyList = [[[WFBusiness alloc] init] PropertyKeys];
for (NSString *key in propertyList)
{
[bus setValue:[obj objectForKey:key] forKey:key];
}
[businessArr addObject:bus];
NSLog(@"photo is %@", [bus categories]);
}
}
NSLog(@"businessArr count is %lu", [businessArr count]);
self.Businesses = businessArr;
return self;
}
@end
完整的封装类WFHTTPRequest。它用于创建一个连接，并发送请求，管理整个应用出现的网络连接，创建一个单例，全局唯一。
//
// WFRequest.h
// WFSearch
//
// Created by ForrestWoo on 14-8-30.
// Copyright (c) 2014年 ForrestWoo. All rights reserved.
//
#import <Foundation/Foundation.h>
@class WFHTTPRequest;
@protocol WFRequestDelegate <NSObject>
@optional
- (void)request:(WFHTTPRequest *)request didfinishloadingWithResult:(id)aResult;
- (void)request:(WFHTTPRequest *)request didfailWithError:(NSError *)aError;
@end
@interface WFHTTPRequest : NSObject
@property (nonatomic, unsafe_unretained) id<WFRequestDelegate> delegate;
@property (nonatomic, strong) NSString *aUrl;
@property (nonatomic, strong) NSDictionary *aParams;
@property (nonatomic, strong) NSArray *connections;
+ (WFHTTPRequest *)sharedInstance;
- (void)createConnectionWithUrl:(NSString *)urlString params:(NSDictionary *)aParams delegate:(id<WFRequestDelegate>)aDelegate;
- (void) cancel;
- (NSString *)getRootURL;
//api
- (void)findBusinessesWithParams:(NSDictionary *)aParams delegate:(id<WFRequestDelegate>)aDelegate;
- (void)findCityWithDelegate:(id<WFRequestDelegate>)aDelegate;
- (void)getCategoriesForBusinessesWithDelegate:(id<WFRequestDelegate>)aDelegate;
@end
//
// WFRequest.m
// WFSearch
//
// Created by ForrestWoo on 14-8-30.
// Copyright (c) 2014年 ForrestWoo. All rights reserved.
//
#import "WFHTTPRequest.h"
#import "WFConstants.h"
#import "SHA1.h"
@interface WFHTTPRequest () <NSURLConnectionDataDelegate>
//- (void)appendUTF8Body:(NSMutableData *)aBody dataString:(NSString *)aDataString;
//- (NSDictionary *)parseQueryString:(NSString *)query;
////- (void)handleResponseData:(NSData *)data;
//- (NSString *)generateFullURL:(NSString *)url;
////- (void)addConnection;
//- (NSString *)serializeURL:(NSString *)aBaseURL params:(NSDictionary *)aParams;
@end
static WFHTTPRequest *sharedObj = nil;
@implementation WFHTTPRequest
{
NSURLConnection *_connection;
NSMutableData *_responseData;
}
- (NSString *)getRootURL
{
return kDPDomain;
}
- (NSString *)generateFullURL:(NSString *)url
{
NSMutableString *str = [[NSMutableString alloc] initWithCapacity:0];
[str appendString:[self getRootURL]];
[str appendString:url];
return str;
}
+ (WFHTTPRequest *)sharedInstance
{
static dispatch_once_t pred = 0;
dispatch_once(&pred, ^{
sharedObj = [[super allocWithZone:NULL] init];
});
return sharedObj;
}
+ (id)allocWithZone:(struct _NSZone *)zone
{
return [self sharedInstance];
}
- (void)createConnectionWithUrl:(NSString *)urlString params:(NSDictionary *)aParams delegate:(id<WFRequestDelegate>)aDelegate
{
NSString *urlStr = [self serializeURL:[self generateFullURL:urlString] params:aParams];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:urlStr] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:kWFRequestimeOutInterval];
[request setHTTPMethod:kHttpMethodGET];
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
self.delegate = aDelegate;
// [[[self class] sharedInstance] setConnections:conn];
}
- (void)findBusinessesWithParams:(NSDictionary *)aParams delegate:(id<WFRequestDelegate>)aDelegate
{
[self createConnectionWithUrl:kSearchResto params:aParams delegate:aDelegate];
}
- (void)findCityWithDelegate:(id<WFRequestDelegate>)aDelegate
{
[self createConnectionWithUrl:kSearchCity params:nil delegate:aDelegate];
}
- (void)getCategoriesForBusinessesWithDelegate:(id<WFRequestDelegate>)aDelegate
{
[self createConnectionWithUrl:kCategoriesWithBusinesses params:nil delegate:aDelegate];
}
//- (void)appendUTF8Body:(NSMutableData *)aBody dataString:(NSString *)aDataString
//{
// [aBody appendData:[aDataString dataUsingEncoding:NSUTF8StringEncoding]];
//}
- (NSDictionary *)parseQueryString:(NSString *)query
{
NSMutableDictionary *paramDict = [[NSMutableDictionary alloc] initWithDictionary:0];
NSArray *paramArr = [query componentsSeparatedByString:@"&"];
for (NSString *param in paramArr)
{
NSArray * elements = [param componentsSeparatedByString:@"="];
if ([elements count] <= 1)
{
return nil;
}
NSString *key = [[elements objectAtIndex:0] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *value = [[elements objectAtIndex:1] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
[paramDict setObject:value forKey:key];
}
return paramDict;
}
- (NSString *)serializeURL:(NSString *)aBaseURL params:(NSDictionary *)aParams
{
NSURL* parsedURL = [NSURL URLWithString:[aBaseURL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSMutableDictionary *paramsDic = [NSMutableDictionary dictionaryWithDictionary:[self parseQueryString:[parsedURL query]]];
if (aParams) {
[paramsDic setValuesForKeysWithDictionary:aParams];
}
NSMutableString *signString = [NSMutableString stringWithString:kDPAppKey];
NSMutableString *paramsString = [NSMutableString stringWithFormat:@"appkey=%@", kDPAppKey];
NSArray *sortedKeys = [[paramsDic allKeys] sortedArrayUsingSelector: @selector(compare:)];
for (NSString *key in sortedKeys) {
[signString appendFormat:@"%@%@", key, [paramsDic objectForKey:key]];
[paramsString appendFormat:@"&%@=%@", key, [paramsDic objectForKey:key]];
}
NSString *str = kDPAppSecret;
[signString appendString:str];
NSData *stringBytes = [signString dataUsingEncoding: NSUTF8StringEncoding];
NSString *digestString = [SHA1 getSHAString:stringBytes];
if (digestString)
{
[paramsString appendFormat:@"&sign=%@", [digestString uppercaseString]];
NSLog(@"...%@...", [NSString stringWithFormat:@"%@://%@%@?%@", [parsedURL scheme], [parsedURL host], [parsedURL path], [paramsString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]);
return [NSString stringWithFormat:@"%@://%@%@?%@", [parsedURL scheme], [parsedURL host], [parsedURL path], [paramsString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}
else
{
return nil;
}
}
- (void) cancel
{
[_connection cancel];
}
+ (NSString *)getParamValueFromURL:(NSString *)aURl paramName:(NSString *)aParamName
{
return nil;
}
#pragma mark - NSURLConnection Delegate Methods
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
_responseData = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[_responseData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSError *error = nil;
id result= [NSJSONSerialization JSONObjectWithData:_responseData options:NSJSONReadingAllowFragments error:&error];
if (!result)
{
NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:error,@"error", nil];
NSError *err = [NSError errorWithDomain:@"domain is error" code:-1 userInfo:userInfo];
if ([self.delegate respondsToSelector:@selector(request:didfailWithError:)])
{
[self.delegate request:self didfailWithError:err];
}
}
else
{
NSString *status = 0;
if ([result isKindOfClass:[NSDictionary class]])
{
status = [result objectForKey:@"status"];
}
if ([status isEqualToString:@"OK"])
{
if ([self.delegate respondsToSelector:@selector(request:didfinishloadingWithResult:)])
{
[self.delegate request:self didfinishloadingWithResult:result == nil ?
_responseData : result];
}
}
else
{
if ([status isEqualToString:@"ERROR"])
{
//TODO:错误处理代码。
}
}
}
// NSString *str = [[NSString alloc] initWithData:_responseData encoding:NSUTF8StringEncoding];
// NSLog(@"_responseData:%@", str);
// [self clearData];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"ERROR!%@", error.description);
}
- (void)clearData
{
_responseData = nil;
[_connection cancel];
_connection = nil;
}
@end
代码下载。下节详细介绍数据解析和网络编程，反射（运行时）