Code sharing of systematic methods for XML data parsing

XML is a self-describing data exchange format. It is a very important data exchange format that has been used in various computer languages ​​for many years. XML is similar to HTML, with pairs of tags, and the format is stricter than HTML, starting with a and ending with a >.

The parsed content is:

<users>
    <user id="001">
        <name>张三</name>
        <password>123456</password>
        <nickname>小张</nickname>
        <description>1111111111</description>
    </user>
     
    <user id="002">
        <name>张三</name>
        <password>2222222</password>
        <nickname>小四儿</nickname>
        <description>李四是个好学生</description>
    </user>
     
    <user id="003">
        <name>张三</name>
        <password>88888888</password>
        <nickname>小五</nickname>
        <description>1234567890</description>
    </user>
     
</users>

has been prepared in advance Read and store the data in data.
Create a class,Inheritfrom NSObject,name it userInfo

@property(nonatomic,copy)NSString *uID;
@property(nonatomic,copy)NSString *name;
@property(nonatomic,copy)NSString *password;
@property(nonatomic,copy)NSString *nickname;
@property(nonatomic,copy)NSString *description;

Create another class, also inherit from NSObject,name it userParser , implement reading of xml files.

userParser.h

#import <Foundation/Foundation.h>
#import "user.h"
@interface userParser : NSObject<NSXMLParserDelegate>
//存储信息的数组
@property(nonatomic,retain)NSMutableArray *array;
//实例
@property(nonatomic,retain)user *people;
//创建字符串保存信息
@property(nonatomic,copy)NSMutableString *buffer;
//读取xml文件
-(void)parserWithString:(NSString *)string;
@end

userparser.m

#import "userParser.h"
 
@implementation userParser
-(void)parserWithString:(NSString *)string
{
    //使用系统XML解析方法
    NSXMLParser *parser=[[NSXMLParser alloc]initWithData:[string dataUsingEncoding:NSUTF8StringEncoding]];
    //设置代理
    parser.delegate=self;
    //开始解析
    [parser parse];
}
#pragma mark ---NSXMLParserDelegate---
//开始解析
- (void)parserDidStartDocument:(NSXMLParser *)parser
{
    NSLog(@"it begin");
}
//解析结束
- (void)parserDidEndDocument:(NSXMLParser *)parser
{
    NSLog(@"it is over");
    for (int i=0; i<_array.count; i++) {
        user *user=_array[i];
        NSLog(@"%@,%@,%@,%@,%@",user.uID,user.name,user.password,user.nickname,user.description);
    }
}
//遇到开始标签
//attributeDict标签属性
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI 
qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"users"]) {
        _array=[[NSMutableArray alloc]init];
    }
    else if ([elementName isEqualToString:@"user"])
    {
        _people=[[user alloc]init];
        //<user id="3">
        _people.uID=[attributeDict objectForKey:@"id"];
    }
    else if ([elementName isEqualToString:@"name"])
    {
        _buffer=[[NSMutableString alloc]init];
    }
    else if ([elementName isEqualToString:@"password"])
    {
        _buffer=[[NSMutableString alloc]init];
    }
    else if ([elementName isEqualToString:@"nickname"])
    {
        _buffer=[[NSMutableString alloc]init];
    }
    else if ([elementName isEqualToString:@"description"])
    {
        _buffer=[[NSMutableString alloc]init];
    }
     
}
//结束标签
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    if ([elementName isEqualToString:@"name"]) {
        _people.name=_buffer;
    }
    else if ([elementName isEqualToString:@"password"])
    {
        _people.password=_buffer;
    }
    else if ([elementName isEqualToString:@"nickname"])
    {
        _people.nickname=_buffer;
    }else if ([elementName isEqualToString:@"description"])
    {
        _people.description=_buffer;
    }
    else if ([elementName isEqualToString:@"user"])
    {
        [_array addObject:_people];
    }
}
//读取内容
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    //NSCharacterSet字符串结合,取出字符串中的空格
    [_buffer appendString:[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]];
}

In the viewcontroller, create an instance of userparserObject, Data parsing is implemented through the parserWithString method

userParser *uparser=[[userParser alloc]init];
[uparser parserWithString:user];

Note: Writing data parsing and interface display separately helps reduce the coupling of the program, and it also conforms to theMVCprogramming pattern.

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