iOS應用開發中資料互動格式是重要知識點。目前比較流行的資料互動格式有JSON (JavaScript Object Notation), XML(Extensible Markup Language)和HTML(Hypertext Markup Language) 。JSON具有佔頻寬小、易用性、跨平臺語言等特點，它在網路資料互動領域佔有重要一席。ios5已經支援原生態的JSON庫了。

UT確保資料解析方式和結果正確。以下內容介紹了JSON和XML的使用方式。

#import "DataParseTest.h"

@interface DataParseTest ()  <NSXMLParserDelegate>{
    int testSize;
    NSMutableString *currentXmlParserString;
}
@end


@implementation DataParseTest


/**
*  ios5 use native json tool. before ios5 we need to use third library JSONKit.
*  Json is better than xml data transfer format in mobile devie.
*/
-(void)testJsonParser{
    
    NSError *error = nil;
    
    NSString *dataStr = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"json"];
    NSData *data = [NSData dataWithContentsOfFile:dataStr];
    
    NSDictionary *weatherDic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:&error];
    
    NSAssert(weatherDic != nil, @"Json value is not nil");
    NSDictionary *weatherInfo = [weatherDic objectForKey:@"weatherinfo"];
    NSEnumerator *emumerator = [weatherInfo keyEnumerator];
    id object;
    while (object = [emumerator nextObject]) {
        NSLog(@"key is %@",object);
        id objectValue = [weatherInfo objectForKey:object];
        if(objectValue)
            NSLog(@"value is %@",objectValue);
    }
}


/**
 *  test XML parser.
 */
-(void)testXMLParser{
    testSize= 0;
    currentXmlParserString = [[NSMutableString alloc] init];
    NSString *dataStr = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"xml"];
    NSData *data = [NSData dataWithContentsOfFile:dataStr];
    NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithData:data];
    [xmlParser setDelegate:self];
    NSAssert([xmlParser parse],@"parse error!");
    NSAssert(testSize == 3, @"can not parse totally.");
}


// Reduce potential parsing errors by using string constants declared in a single place.
static NSString * const kCommonElementName = @"COMMON";
static NSString * const kBotanicalElementName = @"BOTANICAL";
static NSString * const kZoneElementName = @"ZONE";
static NSString * const kLightElementName= @"LIGHT";
static NSString * const kPriceElementName= @"PRICE";
static NSString * const kAvaliabilityElementName= @"AVAILABILITY";


#pragma mark - NSXMLParser delegate methods
/** you can save you data while do parsing **/

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict {
    if ([elementName isEqualToString:kCommonElementName]) {
        
    } else if ([elementName isEqualToString:kBotanicalElementName]) {
        
    }
    [currentXmlParserString setString:@""];

}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
    if ([elementName isEqualToString:kCommonElementName]) {
        NSLog(@"%@",currentXmlParserString);
        testSize++;
    } else if ([elementName isEqualToString:kBotanicalElementName]) {
        
    }
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
    [currentXmlParserString appendString:string];
}


@end
 

<CATALOG>
<PLANT>
<COMMON>======huahua_xiaomi_new</COMMON>
<BOTANICAL>======new_anzhi</BOTANICAL>
<ZONE>======huahua_360</ZONE>
<LIGHT>======new_xiaomi</LIGHT>
<PRICE>======new_baidu</PRICE>
<AVAILABILITY>======new_360</AVAILABILITY>
</PLANT>
<PLANT>
<COMMON>======huahua_jifen</COMMON>
<BOTANICAL>======az_piano_new</BOTANICAL>
<ZONE>======car_anzhi_new</ZONE>
<LIGHT>======qq</LIGHT>
<PRICE>======360</PRICE>
<AVAILABILITY>======wandoujia</AVAILABILITY>
</PLANT>
<PLANT>
<COMMON>======xiaomi</COMMON>
<BOTANICAL>======baidu</BOTANICAL>
<ZONE>======anzhi</ZONE>
<LIGHT>sssssshttp://dd.myapp.com/16891/672D499A2FD2B819B0601DD9E9C07CBF.apk---.jpg---com.heibanxuexi---兒童彈木琴(破解版)---辣媽必備快樂助手彈木琴,學音樂。---11---0===;</LIGHT></span></span>
<PRICE>======jf_huahua</PRICE></span>
<AVAILABILITY>======xm_huahua</AVAILABILITY>
</PLANT>
</CATALOG>
 

{"weatherinfo":{"city":"北京","city_en":"beijing","date_y":"2014年3月4日","date":"","week":"星期二","fchh":"11","cityid":"101010100","temp1":"8℃~-3℃","temp2":"8℃~-3℃","temp3":"7℃~-3℃","temp4":"8℃~-1℃","temp5":"10℃~1℃","temp6":"10℃~2℃","tempF1":"46.4℉~26.6℉","tempF2":"46.4℉~26.6℉","tempF3":"44.6℉~26.6℉","tempF4":"46.4℉~30.2℉","tempF5":"50℉~33.8℉","tempF6":"50℉~35.6℉","weather1":"晴","weather2":"晴","weather3":"晴","weather4":"晴轉多雲","weather5":"多雲","weather6":"多雲","img1":"0","img2":"99","img3":"0","img4":"99","img5":"0","img6":"99","img7":"0","img8":"1","img9":"1","img10":"99","img11":"1","img12":"99","img_single":"0","img_title1":"晴","img_title2":"晴","img_title3":"晴","img_title4":"晴","img_title5":"晴","img_title6":"晴","img_title7":"晴","img_title8":"多雲","img_title9":"多雲","img_title10":"多雲","img_title11":"多雲","img_title12":"多雲","img_title_single":"晴","wind1":"北風4-5級轉微風","wind2":"微風","wind3":"微風","wind4":"微風","wind5":"微風","wind6":"微風","fx1":"北風","fx2":"微風","fl1":"4-5級轉小於3級","fl2":"小於3級","fl3":"小於3級","fl4":"小於3級","fl5":"小於3級","fl6":"小於3級","index":"寒冷","index_d":"天氣寒冷，建議著厚羽絨服、毛皮大衣加厚毛衣等隆冬服裝。年老體弱者尤其要注意保暖防凍。","index48":"冷","index48_d":"天氣冷，建議著棉服、羽絨服、皮夾克加羊毛衫等冬季服裝。年老體弱者宜著厚棉衣、冬大衣或厚羽絨服。","index_uv":"中等","index48_uv":"中等","index_xc":"較適宜","index_tr":"一般","index_co":"較舒適","st1":"7","st2":"-3","st3":"8","st4":"0","st5":"7","st6":"-1","index_cl":"較不宜","index_ls":"基本適宜","index_ag":"易發"}}