使用python自带的xml.dom创建和解析xml

    python中的xml.dom模块使用的就是传统的dom解析api和方法。所以也就不写什么了，主要就是练习敲敲代码，继续熟悉python。本文通过xml.dom.minidom创建一个xml文档，然后再解析出来，用以熟悉相关接口方法的使用。

创建一个xml文档：

'''
Created on 2012-1-10
Create a xml document
@author: xiaojay
'''

from xml.dom import minidom

doc = minidom.Document()
doc.appendChild(doc.createComment("This is a simple xml."))
booklist = doc.createElement("booklist")
doc.appendChild(booklist)

def addBook(newbook):
    book = doc.createElement("book")
    book.setAttribute("id", newbook["id"])
    
    title = doc.createElement("title")
    title.appendChild(doc.createTextNode(newbook["title"]))
    book.appendChild(title)
    
    author = doc.createElement("author")
    name = doc.createElement("name")
    firstname = doc.createElement("firstname")
    firstname.appendChild(doc.createTextNode(newbook["firstname"]))
    lastname = doc.createElement("lastname")
    lastname.appendChild(doc.createTextNode(newbook["lastname"]))
    name.appendChild(firstname)
    name.appendChild(lastname)
    author.appendChild(name)
    book.appendChild(author)
    
    pubdate = doc.createElement("pubdate")
    pubdate.appendChild(doc.createTextNode(newbook["pubdate"]))
    book.appendChild(pubdate)
    
    booklist.appendChild(book)

addBook({"id":"1001","title":"An apple","firstname":"Peter","lastname":"Zhang","pubdate":"2012-1-12"})
addBook({"id":"1002","title":"Love","firstname":"Mike","lastname":"Li","pubdate":"2012-1-10"})
addBook({"id":"1003","title":"Steve.Jobs","firstname":"Tom","lastname":"Wang","pubdate":"2012-1-19"})
addBook({"id":"1004","title":"Harry Potter","firstname":"Peter","lastname":"Chen","pubdate":"2012-11-11"})

f = file("book.xml","w")
doc.writexml(f)
f.close()

　　通过doc.toprettyxml(indent, newl, encoding)方法可以优雅显示xml文档，但是要避免直接写入文本，否则会给解析带来麻烦，尽量使用自带的writexml方法。

生成的文档内容：

<?xml version="1.0" ?>
<!--This is a simple xml.-->
<booklist>
　　<book id="1001">
　　　　<title>
　　　　An apple
　　　　</title>
　　<author>
　　　　<name>
　　　　　　<firstname>
　　　　　　Peter
　　　　　　</firstname>
　　　　　　<lastname>
　　　　　　Zhang
　　　　　　</lastname>
　　　　</name>
　　</author>
　　<pubdate>
　　2012-1-12
　　</pubdate>
　　</book>

 .................
</booklist>

 

解析该xml文档：

'''
Created on 2012-1-10
Scan a xml doc
@author: xiaojay
'''

from xml.dom import minidom , Node

class bookscanner:
    def __init__(self,doc):
        for child in doc.childNodes :
            if child.nodeType == Node.ELEMENT_NODE \
            and child.tagName == "book" :
                bookid = child.getAttribute("id")
                print "*"*20
                print "Book id : " , bookid
                self.handle_book(child)
                
    def handle_book(self,node):
        for child in node.childNodes :
            if child.nodeType == Node.ELEMENT_NODE :
                if child.tagName == "title":
                    print "Title : " , self.getText(child.firstChild)
                if child.tagName == "author":
                    self.handle_author(child)
                if child.tagName == "pubdate":
                    print "Pubdate : " , self.getText(child.firstChild)
            
    def getText(self,node):
        if node.nodeType == Node.TEXT_NODE :
            return node.nodeValue
        else: return ""
        
    def handle_author(self,node):
        author = node.firstChild
        for child in author.childNodes:
            if child.nodeType == Node.ELEMENT_NODE:
                if child.tagName == "firstname" :
                    print "Firstname : ", self.getText(child.firstChild)
                if child.tagName == "lastname" :
                    print "Lastname : " , self.getText(child.firstChild)
    
    
doc = minidom.parse("book.xml")
for child in doc.childNodes :
    if child.nodeType == Node.COMMENT_NODE:
        print "Conment : " , child.nodeValue
    if child.nodeType == Node.ELEMENT_NODE:
        bookscanner(child)

　　

输出结果：

Conment : This is a simple xml.
********************
Book id : 1001
Title : An apple
Firstname : Peter
Lastname : Zhang
Pubdate : 2012-1-12
********************
Book id : 1002
Title : Love
Firstname : Mike
Lastname : Li
Pubdate : 2012-1-10
********************
Book id : 1003
Title : Steve.Jobs
Firstname : Tom
Lastname : Wang
Pubdate : 2012-1-19
********************
Book id : 1004
Title : Harry Potter
Firstname : Peter
Lastname : Chen
Pubdate : 2012-11-11