XML-related technology learning Summary

1. Basic Knowledge (Extensible Markup Language)

 
<? XML version = "1.0"?> <Note> <to> Tove </to> <from> Jani </from>  

 
 
 
  
 
   
Good format (guaranteed by its own syntax)
 
   
Validity (guaranteed by DTD or schema)
 
  
 

 
 
2. DTD (document type definition)
 

 
1) Internal DTD
 

 <?  XML version = "1.0"  ?> 
 <!  Doctype note [
<! Element note (to, from, heading, body) > 
 <!  Element to (# pcdata)  > 
 <!  Element from (# pcdata)  > 
 <!  Element heading (# pcdata)  > 
 <!  Element body (# pcdata)  > 
]>
 < Note  > 
 <  To  > Tove </  To  > 
 <  From  > Jani </  From  > 
 <  Heading > Reminder </  Heading  > 
 <  Body  > Don't forget me this weekend </  Body  > 
 </  Note  > 
 
2) External DTD
 

 
Note. xml
 

 <? XML version = "1.0"  ?> 
 <!  Doctype note system "note. DTD"  > 
 <  Note  > 
 <  To  > Tove </  To  > 
 < From  > Jani </  From  > 
 <  Heading  > Reminder </  Heading  > 
 <  Body  > Don't forget me this weekend! </ Body  > 
 </  Note  > 
 
Note. DTD
 

<!Element note (to, from, heading, body)>
<!Element to (# pcdata)>
<!Element from (# pcdata)>
<!Element heading (# pcdata)>
<!Element body (# pcdata)>
 
 
Why use DTD?
 


 
 
 
  
 
   
Self-description
 
   
It can be used for information exchange.
 
  
 

 
 
3) XML Schema
 

Note. xml
 

 <?  XML version = "1.0"  ?> 

 <  Note
  Xmlns  = "Http://www.w3schools.com"  
Xmlns: xsi  = "Http://www.w3.org/2001/XMLSchema-instance"  
Xsi: nonamespaceschemalocation  = "Note. XSD"  > 
 <  -- Xsi: schemalocation = "Http://www.w3schools.com note. XSD"  --  > 
 <  To  > Tove </  To  > 
 <  From  > Jani </  From  > 
<  Heading  > Reminder </  Heading  > 
 <  Body  > Don't forget me this weekend! </  Body  > 
 </  Note  > 
 
Note. XSD
 

<?  XML version = "1.0"  ?> 
 <  Xs: Schema  Xmlns: XS  = "Http://www.w3.org/2001/XMLSchema"  
Targetnamespace  = "Http://www.w3schools.com"  
Xmlns  = "Http://www.w3schools.com"  
Elementformdefault  = "Qualified"  > 

<  Xs: Element  Name  = "NOTE"  > 
 <  Xs: complextype  > 
 <  Xs: Sequence  > 
 <  Xs: Element  Name  = ""  Type = "XS: string"  /> 
 <  Xs: Element  Name  = "From"  Type  = "XS: string"  /> 
 <  Xs: Element  Name  = "Heading"  Type  = "XS: string"  /> 
<  Xs: Element  Name  = "Body"  Type  = "XS: string"  /> 
 </  Xs: Sequence  > 
 </  Xs: complextype  > 
 </  Xs: Element  > 

 </  Xs: Schema  > 
 
Why use schema?
 


 
 
 
  
 
   
Supports more Data Type Definitions
 
   
You can use XML syntax
 
   
Ensure correct data exchange
 
   
Scalable
 
   
Good form does not meet requirements
 
  
 

 
 
The above is the overall content of http://www.w3schools.com.
 

 
4) document addressing language xpath
 

 
Document addressing language XPath is a member of the XSL (Extensible Stylesheet Language) family. It is also the common basis for XML-related technologies such as XSLT, xpointer, and XQuery.
 

 
From the perspective of XPath, the entire XML document tree consists of a series of nodes.
 

 
5) XML Parsing Method
 


 

 
  
 
   
 SAX (Event-based parsing method, partial loading) 
 
   
 dom (loading all, too much memory consumption, improvement method: loading subtree, delayed reading) 
 
   
 XML beans architecture (using XML schema to generate helper classes) 
 
   
 the Java architecture for Java binding (jaxb)