简介Objective-C解析XML与JSON数据格式的方法
时间：2021-09-04 09:48:51|栏目：iOS代码|点击： 次
解析XML
本文以解析本地XML为例，网络获取到的返回值只需转换成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>用户信息</message> <user> <name>芳仔小脚印</name> <age>10</age> <school>JiangSu University</school> </user> <user> <name>毒虫</name> <age>22</age> <school>NanJing University</school> </user> <user> <name>女神</name> <age>23</age> <school>HongKong University</school> </user> </AllUsers>
我们用一个数组来存放，最终数据结构为
(
{
message = "用户信息";
},
{
age = 10;
name = "芳仔小脚印";
school = "JiangSu University";
},
{
age = 22;
name = "毒虫";
school = "NanJing University";
},
{
age = 23;
name = "女神";
school = "HongKong University";
}
)
解析步骤
一、声明代理 NSXMLParserDelegate
二、解析
复制代码 代码如下:
// 遇到节点message和user时作为一个字典存放
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];
// 获取xml文件的路径
NSString *xmlPath = [[NSBundle mainBundle] pathForResource:@"users" ofType:@"xml"];
// 转化为Data
NSData *data = [[NSData alloc] initWithContentsOfFile:xmlPath];
// 初始化
NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithData:data];
// 代理
xmlParser.delegate = self;
// 开始解析
BOOL flag = [xmlParser parse];
if (flag) {
NSLog(@"解析成功");
}
else{
NSLog(@"解析出错");
}
中间变量，在.m的interface的中定义
复制代码 代码如下:
NSString *currentElement;
NSString *currentValue;
NSMutableDictionary *rootDic;
NSMutableArray *finalArray;
代理方法
复制代码 代码如下:
#pragma - mark 开始解析时
-(void)parserDidStartDocument:(NSXMLParser *)parser
{
// 用数组存储每一组信息
finalArray = [[NSMutableArray alloc] init];
}
#pragma - mark 发现节点时
-(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]) {
// 关键节点开始时，初始化一个字典来存放值
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 发现节点值时
-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
if (currentElement) {
currentValue = string;
[rootDic setObject:string forKey:currentElement];
}
}
#pragma - mark 结束节点时
-(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]) {
// 关键节点结束时，将字典存放在数组中
if (rootDic) {
[finalArray addObject:rootDic];
}
}
}
}
#pragma - mark 结束解析
-(void)parserDidEndDocument:(NSXMLParser *)parser
{
}
解析完成后，打印出finalArray为
(
{
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
使用开源json包，项目地址：
http://www.superloopy.io/json-framework/
复制代码 代码如下:
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解析对象
[parser release];
//发送者
NSString * sender = [dicMessageInfo objectForKey:@"sender"];
2.json嵌套对象解析：
复制代码 代码如下:
//要上传的字符串
NSString *dataStr=[[NSString alloc] initWithString:@"{\"cross\":{\"1\":\"true\",\"2\":\"false\",\"3\":\"true\"}}"];
//获取响应返回字符串
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解析对象
NSMutableDictionary * cross = [dicMessageInfo objectForKey:@"cross"];
NSString *cross1= [cross objectForKey:@"1"];
//解析json到各个字符串
//发送者
[parser release];
NSLog(@"cross1: %@",cross1);
3.拼接json字符串
通过使用SBJson中的SBJsonWriter类的方法- (NSString*)stringWithObject:(id)value可以将一个对象中的值格式化为json字符串，符合key/value格式的数据封装到NSDictionary后可以使用该方法进行格式化，其他数据通过拼接字符串的方式格式化。
在拼接过程中可以使用类NSMutableString的方法：
复制代码 代码如下:
- (void)appendString:(NSString *)aString;、
- (void)appendFormat:(NSString *)format, ... NS_FORMAT_FUNCTION(1,2);
动态添加字符串。
拼接的字符串可通过json在线验证的方式验证其格式是否正确，网址为：
http://jsonlint.com/
复制代码 代码如下:
-(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.利用多个NSDictionary，拼接多层嵌套的json字符串，减少因手工拼接忘记加引号导致的json格式错误
示例代码：
复制代码 代码如下:
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);
