[课堂实践与项目]XML解析的两种方式：DOM和SAX

XML解析主要有两种方式：DOM第三方的解析和Sax官方的解析。

1.DOM解析

2）导入静态库

// libxml includes require that the target Header Search Paths contain
//
//   /usr/include/libxml2
//
// and Other Linker Flags contain
//
//   -lxml2

3）导入libxml2库

4）我们先看看我们写的 xml文件

<?xml version ="1.0" encoding = "utf-8" ?>

<student_list>
<student>
<stu_num>001</stu_num>
<stu_name>李蝉</stu_name>
<stu_class>一班</stu_class>
</student>

<student>
<stu_num>002</stu_num>
<stu_name>李2</stu_name>
<stu_class>二班</stu_class>
</student>

</student_list>

5）解析的代码如下：

- (IBAction)domParser:(id)sender {
    //首先获取 我们的xml文件的路径，并获得相应的 xml文件的字符串
    NSString *path = [[NSBundle mainBundle]pathForResource:@"student_list" ofType:@"xml"];
    
    NSString *xmlString = [[NSString alloc]initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    
    
    NSLog(@"%@",xmlString);
    //传送给解析器

//把string封装成  GdataxMLDocument ，准备解析
    GdataxMLDocument *document = [[GdataxMLDocument alloc]initWithXMLString:xmlString options:0 error:nil];
    //依据我们的XML文件 获得根节点
    GdataxMLElement *rootElement = [document rootElement];
    //获得  root节点下 的    student 节点的所有。
    NSArray *stuArr = [rootElement elementsForName:@"student"];
    
    //对 student节点进行输出
    for (GdataxMLNode *node in stuArr) {
        
        

        NSLog(@"-------------student-------");
        
        for (int i = 0; i < [node childCount]; i++) {
            
            NSArray * infoArr = [node children];
            
            GdataxMLNode *infoNode = [infoArr objectAtIndex:i];
            
            switch (i) {
                case 0:
                {
                [self.textString appendFormat:@"stu_num%@\n",[infoNode  stringValue] ];
                    NSLog(@"%@",[infoNode  stringValue]);
                    NSLog(@"%@",self.textString);
                break;
                }
                case 1:
                [self.textString appendFormat:@"stu_name%@ \n",[infoNode  stringValue] ];
                break;
                case 2:
                [self.textString appendFormat:@"stu_class%@ \n",[infoNode  stringValue]];
                
                break;
                default:
                break;
            }
        }
        
        
    }
    
    
    self.textView.text = self.textString;
    
    NSLog(@"view:%@",self.textString);
   
    
    
}

2.SAX解析

sax解析主要是依赖代理的方法进行的。NSXMLParserDelegate

1）sax解析的前期准备，配置xml文件以及设置delegate代理

- (IBAction)saxParser:(id)sender {
    
    NSString *path = [[NSBundle mainBundle]pathForResource:@"student_list" ofType:@"xml"];
    
 
    NSData *data = [NSData dataWithContentsOfFile:path];
    
    NSXMLParser *parser = [[NSXMLParser alloc]initWithData:data];
    
    parser.delegate = self;
    
    [parser parse];
   
}

2）NSXMLParserDelegate代理文件

- (void)parserDidStartDocument:(NSXMLParser *)parser
    {

//在  解析doument的开始调用。
        NSLog(@"文档解析开始");
    }
    
    - (void)parserDidEndDocument:(NSXMLParser *)parser
    {

//解析结束时调用
        NSLog(@"文档解析结束");
    }
    

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

//解析一个标签的时候调用，如果我们想得到的只是某个标签，只要设置对应的elementName ，并设置全局变量的真假 ，然后在parser中进行性的输出就行了。
        NSLog(@"标签开始");
        
        NSLog(@"didStartElement %@",elementName);
        
        if ([elementName  isEqualToString:@"stu_name"]) {
            print = YES;
        }
        
        
    }
    

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

//解析一个标签结束时候调用
        NSLog(@"标签结束");
         NSLog(@"didEndElement %@",elementName);
    
    
    }
     
    - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
    {
     //得到对应的标签的内部数据   
        if (print) {
            
            NSLog(@"Data：%@",string);
            
            print = YES;
        }
       

    
    }

//不进行限制时候的情况：

2014-01-01 17:53:04.597 XML解析[8050:a0b] 文档解析开始

2014-01-01 17:53:04.597 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.597 XML解析[8050:a0b] didStartElement student_list

2014-01-01 17:53:04.598 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.598 XML解析[8050:a0b] didStartElement student

2014-01-01 17:53:04.598 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.598 XML解析[8050:a0b] didStartElement stu_num

2014-01-01 17:53:04.598 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.599 XML解析[8050:a0b] didEndElement stu_num

2014-01-01 17:53:04.599 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.599 XML解析[8050:a0b] didStartElement stu_name

2014-01-01 17:53:04.599 XML解析[8050:a0b] Data：李蝉

2014-01-01 17:53:04.599 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.600 XML解析[8050:a0b] didEndElement stu_name

2014-01-01 17:53:04.600 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.600 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.600 XML解析[8050:a0b] didStartElement stu_class

2014-01-01 17:53:04.600 XML解析[8050:a0b] Data：一班

2014-01-01 17:53:04.600 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.600 XML解析[8050:a0b] didEndElement stu_class

2014-01-01 17:53:04.601 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.601 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.601 XML解析[8050:a0b] didEndElement student

2014-01-01 17:53:04.601 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.601 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.601 XML解析[8050:a0b] didStartElement student

2014-01-01 17:53:04.602 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.602 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.602 XML解析[8050:a0b] didStartElement stu_num

2014-01-01 17:53:04.602 XML解析[8050:a0b] Data：002

2014-01-01 17:53:04.602 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.602 XML解析[8050:a0b] didEndElement stu_num

2014-01-01 17:53:04.602 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.603 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.603 XML解析[8050:a0b] didStartElement stu_name

2014-01-01 17:53:04.603 XML解析[8050:a0b] Data：李2

2014-01-01 17:53:04.603 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.603 XML解析[8050:a0b] didEndElement stu_name

2014-01-01 17:53:04.603 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.604 XML解析[8050:a0b] 标签开始

2014-01-01 17:53:04.604 XML解析[8050:a0b] didStartElement stu_class

2014-01-01 17:53:04.604 XML解析[8050:a0b] Data：二班

2014-01-01 17:53:04.604 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.604 XML解析[8050:a0b] didEndElement stu_class

2014-01-01 17:53:04.604 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.604 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.605 XML解析[8050:a0b] didEndElement student

2014-01-01 17:53:04.605 XML解析[8050:a0b] Data：

2014-01-01 17:53:04.605 XML解析[8050:a0b] 标签结束

2014-01-01 17:53:04.605 XML解析[8050:a0b] didEndElement student_list

2014-01-01 17:53:04.605 XML解析[8050:a0b] 文档解析结束

2）进行限制之后

2014-01-01 17:54:06.230 XML解析[8074:a0b] 文档解析开始

2014-01-01 17:54:06.231 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.232 XML解析[8074:a0b] didStartElement student_list

2014-01-01 17:54:06.232 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.233 XML解析[8074:a0b] didStartElement student

2014-01-01 17:54:06.234 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.234 XML解析[8074:a0b] didStartElement stu_num

2014-01-01 17:54:06.235 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.235 XML解析[8074:a0b] didEndElement stu_num

2014-01-01 17:54:06.236 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.237 XML解析[8074:a0b] didStartElement stu_name

2014-01-01 17:54:06.237 XML解析[8074:a0b] Data：李蝉

2014-01-01 17:54:06.238 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.238 XML解析[8074:a0b] didEndElement stu_name

2014-01-01 17:54:06.239 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.239 XML解析[8074:a0b] didStartElement stu_class

2014-01-01 17:54:06.240 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.240 XML解析[8074:a0b] didEndElement stu_class

2014-01-01 17:54:06.241 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.241 XML解析[8074:a0b] didEndElement student

2014-01-01 17:54:06.241 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.242 XML解析[8074:a0b] didStartElement student

2014-01-01 17:54:06.242 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.243 XML解析[8074:a0b] didStartElement stu_num

2014-01-01 17:54:06.243 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.244 XML解析[8074:a0b] didEndElement stu_num

2014-01-01 17:54:06.244 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.245 XML解析[8074:a0b] didStartElement stu_name

2014-01-01 17:54:06.245 XML解析[8074:a0b] Data：李2

2014-01-01 17:54:06.246 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.246 XML解析[8074:a0b] didEndElement stu_name

2014-01-01 17:54:06.247 XML解析[8074:a0b] 标签开始

2014-01-01 17:54:06.247 XML解析[8074:a0b] didStartElement stu_class

2014-01-01 17:54:06.248 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.248 XML解析[8074:a0b] didEndElement stu_class

2014-01-01 17:54:06.249 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.249 XML解析[8074:a0b] didEndElement student

2014-01-01 17:54:06.250 XML解析[8074:a0b] 标签结束

2014-01-01 17:54:06.250 XML解析[8074:a0b] didEndElement student_list

2014-01-01 17:54:06.251 XML解析[8074:a0b] 文档解析结束

对比之后可以看出，虽然也调用了方法，但是因为 print为false，所以并没有打印输出。原文链接：https://www.f2er.com/xml/299334.html

[课堂实践与项目]XML解析的两种方式：DOM和SAX

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