簡介Objective-C解析XML與JSON數(shù)據(jù)格式的方法

更新時間：2016年01月27日 09:20:13 作者：芳草小腳丫

這篇文章主要介紹了Objective-C解析XML與JSON數(shù)據(jù)格式的方法,文中解析JSON包括拼接JSON字符串用到了SBJson這個解析器,需要的朋友可以參考下

解析XML
本文以解析本地XML為例，網(wǎng)絡(luò)獲取到的返回值只需轉(zhuǎn)換成NSData型，解析是同理

需要解析的xml文件如下，users.xml

<?xml version="1.0" encoding="UTF-8"?>
<AllUsers>
 <message>用戶信息</message>
 <user>
  <name>芳仔小腳印</name>
  <age>10</age>
  <school>JiangSu University</school>
 </user>
 <user>
  <name>毒蟲</name>
  <age>22</age>
  <school>NanJing University</school>
 </user>
 <user>
  <name>女神</name>
  <age>23</age>
  <school>HongKong University</school>
 </user>
</AllUsers>

我們用一個數(shù)組來存放，最終數(shù)據(jù)結(jié)構(gòu)為

(
    {
    message = "用戶信息";
  },
    {
    age = 10;
    name = "芳仔小腳印";
    school = "JiangSu University";
  },
    {
    age = 22;
    name = "毒蟲";
    school = "NanJing University";
  },
    {
    age = 23;
    name = "女神";
    school = "HongKong University";
  }
)

解析步驟

一、聲明代理 NSXMLParserDelegate

二、解析

復(fù)制代碼代碼如下:

// 遇到節(jié)點message和user時作為一個字典存放

    NSArray *keyElements = [[NSArray alloc] initWithObjects:@"message",@"user", nil];

    // 需要解析的字段

    NSArray *rootElements = [[NSArray alloc] initWithObjects:@"message",@"name",@"age",@"school", nil];

    // 獲取xml文件的路徑

    NSString *xmlPath = [[NSBundle mainBundle] pathForResource:@"users" ofType:@"xml"];

    // 轉(zhuǎn)化為Data

    NSData *data = [[NSData alloc] initWithContentsOfFile:xmlPath];

    // 初始化

    NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithData:data];

    // 代理

    xmlParser.delegate = self;

    // 開始解析

    BOOL flag = [xmlParser parse];

    if (flag) {

        NSLog(@"解析成功");

    }

    else{

        NSLog(@"解析出錯");

    }

中間變量，在.m的interface的中定義

復(fù)制代碼代碼如下:

NSString *currentElement;

    NSString *currentValue;

    NSMutableDictionary *rootDic;

    NSMutableArray *finalArray;

代理方法

復(fù)制代碼代碼如下:

#pragma - mark 開始解析時

-(void)parserDidStartDocument:(NSXMLParser *)parser

{

    // 用數(shù)組存儲每一組信息

    finalArray = [[NSMutableArray alloc] init];

}

#pragma - mark 發(fā)現(xiàn)節(jié)點時

-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict

{

    for(NSString *key in self.keyElements){

        if ([elementName isEqualToString:key]) {

            // 關(guān)鍵節(jié)點開始時，初始化一個字典來存放值

            rootDic = nil;

            rootDic = [[NSMutableDictionary alloc] initWithCapacity:0];

        }

        else {

            for(NSString *element in self.rootElements){

                if ([element isEqualToString:element]) {

                    currentElement = elementName;

                    currentValue = [NSString string];

                }

            }

        }

    }

}

#pragma - mark 發(fā)現(xiàn)節(jié)點值時

-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string

{

    if (currentElement) {

        currentValue = string;

        [rootDic setObject:string forKey:currentElement];

    }

}

#pragma - mark 結(jié)束節(jié)點時

-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName

{

    if (currentElement) {

        [rootDic setObject:currentValue forKey:currentElement];

        currentElement = nil;

        currentValue = nil;

    }

    for(NSString *key in self.keyElements){

        if ([elementName isEqualToString:key]) {

            // 關(guān)鍵節(jié)點結(jié)束時，將字典存放在數(shù)組中

            if (rootDic) {

                [finalArray addObject:rootDic];

            }

        }

    }

}

#pragma - mark 結(jié)束解析

-(void)parserDidEndDocument:(NSXMLParser *)parser

{

}

解析完成后，打印出finalArray為

(
 {
  message = "\U7528\U6237\U4fe1\U606f";
 },
 {
  age = 10;
  name = "\U82b3\U4ed4\U5c0f\U811a\U5370";
  school = "JiangSu University";
 },
 {
  age = 22;
  name = "\U6bd2\U866b";
  school = "NanJing University";
 },
 {
  age = 23;
  name = "\U5973\U795e";
  school = "HongKong University";
 }
)

使用SBJson拼接和解析json
1.ios解析json
使用開源json包，項目地址：
http://www.superloopy.io/json-framework/

復(fù)制代碼代碼如下:

NSData * responseData = [respones responseData]; 

     NSString * strResponser = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding]; 

SBJsonParser * parser = [[SBJsonParser alloc]init]; 

     NSMutableDictionary *dicMessageInfo = [parser objectWithString:strResponser]; // 解析成json解析對象 

[parser release]; 

     //發(fā)送者 

     NSString * sender = [dicMessageInfo objectForKey:@"sender"];

2.json嵌套對象解析：

復(fù)制代碼代碼如下:

//要上傳的字符串 

    NSString *dataStr=[[NSString alloc] initWithString:@"{\"cross\":{\"1\":\"true\",\"2\":\"false\",\"3\":\"true\"}}"]; 

//獲取響應(yīng)返回字符串 

NSData * responseData = [respones responseData]; 

        NSString * strResponser = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding]; 

//嵌套解析 

SBJsonParser * parser = [[SBJsonParser alloc]init]; 

            NSMutableDictionary *dicMessageInfo = [parser objectWithString:strResponser]; // 解析成json解析對象 

            NSMutableDictionary * cross = [dicMessageInfo objectForKey:@"cross"]; 

            NSString *cross1= [cross objectForKey:@"1"]; 

            //解析json到各個字符串 

            //發(fā)送者 

            [parser release]; 

            NSLog(@"cross1: %@",cross1);

3.拼接json字符串

通過使用SBJson中的SBJsonWriter類的方法- (NSString*)stringWithObject:(id)value可以將一個對象中的值格式化為json字符串，符合key/value格式的數(shù)據(jù)封裝到NSDictionary后可以使用該方法進行格式化，其他數(shù)據(jù)通過拼接字符串的方式格式化。
在拼接過程中可以使用類NSMutableString的方法：

復(fù)制代碼代碼如下:

 
- (void)appendString:(NSString *)aString;、 

- (void)appendFormat:(NSString *)format, ... NS_FORMAT_FUNCTION(1,2);

動態(tài)添加字符串。
拼接的字符串可通過json在線驗證的方式驗證其格式是否正確，網(wǎng)址為：
http://jsonlint.com/

復(fù)制代碼代碼如下:

-(NSString *) getJsonString 

{ 

    NSMutableString *json = [NSMutableString stringWithCapacity:128]; 

    NSString *jsonString=nil; 

    SBJsonWriter *writer = [[SBJsonWriter alloc] init]; 

    [json appendString:@"{\"data\":{"]; 

    [json appendFormat:@"\"%@\":\"%d\",",@"reset",reset]; 

    if(missionStatus!=NULL) 

    { 

        jsonString=[writer stringWithObject:status]; 

        if(jsonString!=NULL) 

        { 

            [json appendString:@"\"status\":"]; 

            [json appendString:jsonString]; 

        } 

    } 

    [json appendString:@"}}"]; 

    return json; 

}

4.利用多個NSDictionary，拼接多層嵌套的json字符串，減少因手工拼接忘記加引號導(dǎo)致的json格式錯誤
示例代碼：

復(fù)制代碼代碼如下:

NSDictionary *dataDictionary= [NSDictionary dictionaryWithObjectsAndKeys:mac,@"mac", 

                                   game,@"game", 

                                   devicetoken,@"devicetoken", 

                                   device,@"device", 

                                   gv,@"gv", 

                                   lang,@"lang", 

                                   os,@"os", 

                                   hardware,@"hardware", 

                                   down,@"down",nil]; 

    NSDictionary *parmDictionary= [NSDictionary dictionaryWithObjectsAndKeys:@"getSession",@"act", 

                                   dataDictionary,@"data",nil]; 

    NSDictionary *jsonDictionary=[NSDictionary dictionaryWithObjectsAndKeys:pv,@"pv", 

                                  parmDictionary,@"param",nil]; 

    SBJsonWriter *writer = [[SBJsonWriter alloc] init]; 

    NSString *jsonString=nil; 

    jsonString=[writer stringWithObject:jsonDictionary]; 

    NSLog(@"%@",jsonString);