Android创建与解析XML（二）——详解Dom方式

1. dom概述

dom方式创建xml，应用了标准xml构造器 javax.xml.parsers.documentbuilder 来创建 xml 文档，需要导入以下内容

javax.xml.parsers

javax.xml.parsers.documentbuilder 

javax.xml.parsers.documentbuilderfactory 

javax.xml.parsers.parserconfigurationexception;
javax.xml.transform

javax.xml.transform.transformerfactory 

javax.xml.transform.transformer 

javax.xml.transform.dom.domsource 

javax.xml.transform.stream.streamresult 

javax.xml.transform.outputkeys;

javax.xml.transform.transformerfactoryconfigurationerror;

javax.xml.transform.transformerconfigurationexception;

javax.xml.transform.transformerexception;

org.w3c.dom 

org.w3c.dom.document;

org.w3c.dom.element;

org.w3c.dom.node;

org.w3c.dom.domexception;

org.w3c.dom.nodelist;

org.xml.sax.saxexception;

创建和解析xml的效果图：

2、dom 创建 xml

dom，借助 javax.xml.parsers.documentbuilder，可以创建 org.w3c.dom.document 对象。

使用来自 documentbuilderfactory 的 documentbuilder 对象在 android 设备上创建与解析 xml 文档。您将使用 xml pull 解析器的扩展来解析 xml 文档。

/** dom方式，创建 xml */ 
public string domcreatexml() { 
  string xmlwriter = null; 
   
  person []persons = new person[3];    // 创建节点person对象 
  persons[0] = new person(1, "sunboy_2050", "//www.jb51.net/"); 
  persons[1] = new person(2, "baidu", "http://wwwbaiducom"); 
  persons[2] = new person(3, "google", "http://wwwgooglecom"); 
   
  try { 
    documentbuilderfactory factory = documentbuilderfactorynewinstance(); 
    documentbuilder builder = factorynewdocumentbuilder(); 
    document doc = buildernewdocument(); 
     
    element eleroot = doccreateelement("root"); 
    elerootsetattribute("author", "homer"); 
    elerootsetattribute("date", "2012-04-26"); 
    docappendchild(eleroot); 
     
    int personslen = personslength; 
    for(int i=0; i<personslen; i++) { 
      element eleperson = doccreateelement("person"); 
      elerootappendchild(eleperson); 
       
      element eleid = doccreateelement("id"); 
      node nodeid = doccreatetextnode(persons[i]getid() + ""); 
      eleidappendchild(nodeid); 
      elepersonappendchild(eleid); 
 
      element elename = doccreateelement("name"); 
      node nodename = doccreatetextnode(persons[i]getname()); 
      elenameappendchild(nodename); 
      elepersonappendchild(elename); 
 
      element eleblog = doccreateelement("blog"); 
      node nodeblog = doccreatetextnode(persons[i]getblog()); 
      eleblogappendchild(nodeblog); 
      elepersonappendchild(eleblog); 
    } 
     
     
    properties properties = new properties(); 
    propertiessetproperty(outputkeysindent, "yes"); 
    propertiessetproperty(outputkeysmedia_type, "xml"); 
    propertiessetproperty(outputkeysversion, "0"); 
    propertiessetproperty(outputkeysencoding, "utf-8"); 
    propertiessetproperty(outputkeysmethod, "xml"); 
    propertiessetproperty(outputkeysomit_xml_declaration, "yes"); 
     
    transformerfactory transformerfactory = transformerfactorynewinstance(); 
    transformer transformer = transformerfactorynewtransformer(); 
    transformersetoutputproperties(properties); 
     
    domsource domsource = new domsource(docgetdocumentelement()); 
    outputstream output = new bytearrayoutputstream(); 
    streamresult result = new streamresult(output); 
    transformertransform(domsource, result); 
     
    xmlwriter = outputtostring(); 
     
  } catch (parserconfigurationexception e) {   // factorynewdocumentbuilder 
    eprintstacktrace(); 
  } catch (domexception e) {           // doccreateelement 
    eprintstacktrace(); 
  } catch (transformerfactoryconfigurationerror e) {   // transformerfactorynewinstance 
    eprintstacktrace(); 
  } catch (transformerconfigurationexception e) {   // transformerfactorynewtransformer 
    eprintstacktrace(); 
  } catch (transformerexception e) {       // transformertransform 
    eprintstacktrace(); 
  } catch (exception e) { 
    eprintstacktrace(); 
  } 
   
  savedxml(filename, xmlwritertostring()); 
   
  return xmlwritertostring(); 
} 

运行结果：

3、dom 解析 xml

dom方式，解析xml是创建xml的逆过程，主要用到了builder.parse(is)进行解析，然后通过tag、nodelist、element、childnotes等得到element和node属性或值。

/** dom方式，解析 xml */ 
public string domresolvexml() { 
  stringwriter xmlwriter = new stringwriter(); 
   
  inputstream is= readxml(filename); 
  try { 
    documentbuilderfactory factory = documentbuilderfactorynewinstance(); 
    documentbuilder builder = factorynewdocumentbuilder(); 
    document doc = builderparse(is); 
 
    docgetdocumentelement()normalize(); 
    nodelist nlroot = docgetelementsbytagname("root"); 
    element eleroot = (element)nlrootitem(0); 
    string attrauthor = elerootgetattribute("author"); 
    string attrdate = elerootgetattribute("date"); 
    xmlwriterappend("root")append("\t\t"); 
    xmlwriterappend(attrauthor)append("\t"); 
    xmlwriterappend(attrdate)append("\n"); 
     
    nodelist nlperson = elerootgetelementsbytagname("person"); 
    int personslen = nlpersongetlength(); 
    person []persons = new person[personslen]; 
    for(int i=0; i<personslen; i++) { 
      element eleperson = (element) nlpersonitem(i);   // person节点 
      person person = new person();            // 创建person对象 
       
      nodelist nlid = elepersongetelementsbytagname("id"); 
      element eleid = (element)nliditem(0); 
      string id = eleidgetchildnodes()item(0)getnodevalue(); 
      personsetid(integerparseint(id)); 
       
      nodelist nlname = elepersongetelementsbytagname("name"); 
      element elename = (element)nlnameitem(0); 
      string name = elenamegetchildnodes()item(0)getnodevalue(); 
      personsetname(name); 
       
      nodelist nlblog = elepersongetelementsbytagname("blog"); 
      element eleblog = (element)nlblogitem(0); 
      string blog = elebloggetchildnodes()item(0)getnodevalue(); 
      personsetblog(blog); 
       
      xmlwriterappend(persontostring())append("\n"); 
      persons[i] = person; 
    } 
     
  } catch (parserconfigurationexception e) {   // factorynewdocumentbuilder 
    eprintstacktrace(); 
  } catch (saxexception e) {   // builderparse 
    eprintstacktrace(); 
  } catch (ioexception e) {    // builderparse 
    eprintstacktrace(); 
  } catch (exception e) { 
    eprintstacktrace(); 
  } 
   
  return xmlwritertostring(); 
} 

运行结果：

4、person类

person类，是创建xml的单位实例，基于java面向对象定义的一个类

public class person { 
  private int id; 
  private string name; 
  private string blog; 
   
  public person() { 
    thisid = -1; 
    thisname = ""; 
    thisblog = ""; 
  } 
 
  public person(int id, string name, string blog) { 
    thisid = id; 
    thisname = name; 
    thisblog = blog; 
  } 
   
  public person(person person) { 
    thisid = personid; 
    thisname = personname; 
    thisblog = personblog; 
  } 
 
  public person getperson(){ 
    return this; 
  } 
   
  public void setid(int id) { 
    thisid = id; 
  } 
   
  public int getid(){ 
    return thisid; 
  } 
   
  public void setname(string name) { 
    thisname = name; 
  } 
 
  public string getname() { 
    return thisname; 
  } 
 
  public void setblog(string blog) { 
    thisblog = blog; 
  } 
 
  public string getblog() { 
    return thisblog; 
  } 
 
  public string tostring() { 
    return "person \nid = " + id + "\nname = " + name + "\nblog = " + blog + "\n"; 
  } 
} 

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。