IOS中XML解析之NSXMLParser

NSXMLParser解析XML数据 用法如下：
一、首先，必须继承NSXMLParserDelegate协议 
@interface ViewController : UIViewController<NSXMLParserDelegate> 
二、设置XML数据，并初始化NSXMLParser： 
1、从本地XML文件中读取数据 
NSString *strPathXml = [[NSBundle mainBundle] pathForResource:@"group" ofType:@"xml"]; 
NSData *xmlData = [[NSData alloc] initWithContentsOfFile:strPathXml];
NSXMLParser *parserXML = [[NSXMLParser alloc] initWithData:xmlData]; 
[parser setShouldProcessNamespaces:NO]; 
[parser setShouldReportNamespacePrefixes:NO]; 
[parser setShouldResolveExternalEntities:NO]; 
[parser setDelegate:self]; 
[parser parse]; 
[parser release]; 
2、从接口Java Servlet中获取数据 
NSString *nstrYwKPIUrl = [[NSString alloc]initWithFormat:@"%@?citys=%@&startTime=%@&endTime=%@&indexNames=%@",YWKPIURL,city,startTime,endTime,zbz]; 
//Servlet访问地址与传递参数 
NSString *encodedURL = [nstrYwKPIUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; 
//对Servlet访问地址进行编码 
NSLog(@"encodedURL is %@",encodedURL); 
NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:[NSURL URLWithString:encodedURL ]]; 
[parser setShouldProcessNamespaces:NO]; 
[parser setShouldReportNamespacePrefixes:NO]; 
[parser setShouldResolveExternalEntities:NO]; 
parser.delegate = self; 
[parser parse]; 
[parser release];
三、解析XML数据 
1、遍例xml的节点，执行以下代理方法 
-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict { 
xmlelement = [[NSString alloc]initWithString:elementName];
 //xmlelement为XML元素节点(xmlelement为字符串变量，是在.h文件中定义的。) 
} 
2、当xml节点有值时，则执行以下代理方法 
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
 if ([xmlelement isEqualToString:@"START_TIME"]) { 
[ywKPI.times addObject:[string substringToIndex:10]];
 } 
//START_TIME XML文件内容节点，ywKPI.times 数组对象，string xml文件START_TIME 节点值。 以下类似。 
if ([xmlelement isEqualToString:@"REGION_USERLABEL"]) { 
[ywKPI.citys addObject:string]; 
} 
if ([xmlelement isEqualToString:@"BHTIME_CS"]) {
 [ywKPI.dlymss addObject:string]; 
} 
if ([xmlelement isEqualToString:@"BHTIME_PS"]) { 
 [ywKPI.fzymss addObject:string]; 
} 
if ([xmlelement isEqualToString:@"GSM_NET_RATE"]) { 
NSString *gsmwljtl =[[NSString alloc]initWithFormat: @"%@%@",[NSString stringWithFormat:@"%.2f",[string floatValue]],@"%"];
 [ywKPI.gsmwljtls addObject:gsmwljtl]; 
} 
} 
3、当遇到XML节点结束标记时，执行以下代理方法 
-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName { 
xmlelement = nil;
//xmlelement为字符串变量，是在.h文件中定义的。 
}