初探iOS网络开发，数据解析。

2022-11-29 09:47:20

　　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）

码农公寓

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