上篇我們使用XmlSerializer創建的xml文件，發現了些問題，那樣的xml文件是不標準的，只能自己創建自己讀，而不能供給譬如opencv的FileStorage來讀取。而且，opencv能夠讀取的xml文件還有着其他嚴格的格式控制，下面簡單介紹一下。如下所示：
<?xml version="1.0"
encoding="utf-8"?>
<opencv_storage>
<person>
<_>
<x>90</x>
</_>
</person>
</opencv_storage>
其中：<opencv_storage>是必須要有的，貌似是一個標誌神馬，<_>也是必須要有的，也是一個神馬標誌。我通過以下c++程序來讀取一個這樣的xml文件：
FileStorage fs("b.xml", FileStorage::READ);
if (fs.isOpened())
{
FileNode dbName = fs["person"];
int age;
string strName;
FileNodeIterator it = dbName.begin(), it_end =
dbName.end();
for( size_t i = 0; it != it_end; ++it, i++ )
{
(*it)["name"]>>strName;
cout<<strName
<<endl;
(*it)["x"] >>age ;
cout<<age<<endl;
(*it)["y"] >>age ;
cout<<age<<endl;
}
fs.release();
}
是不是很簡單，opencv 讀取xml文件就是這麼簡單！
下面來看一下如何創建通用的xml文件：
private void
createXmlFile(List<coordinate>
Items,OutputStream out){
try {
DocumentBuilderFactory factory = DocumentBuilderFactory
.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document
doc = builder.newDocument();
Element
rootEle = doc.createElement_x_x_x_x_x("opencv_storage");
doc.a(rootEle);
Element
groupEle = doc.createElement_x_x_x_x_x("person");
for
(coordinate Item : Items)
{
Element
personEle1 = doc.createElement_x_x_x_x_x("_");
Element
chinese0 = doc.createElement_x_x_x_x_x("name");
chinese0.a(doc.createTextNode(String.valueOf(Item.getName())));
personEle1.a(chinese0);
Element
chinese1 = doc.createElement_x_x_x_x_x("x");
chinese1.a(doc.createTextNode(String.valueOf(Item.getX())));
personEle1.a(chinese1);
Element
chinese2 = doc.createElement_x_x_x_x_x("y");
chinese2.a(doc.createTextNode(String.valueOf(Item.getY())));
personEle1.a(chinese2);
groupEle.a(personEle1);
}
rootEle.a(groupEle);
TransformerFactory tf = TransformerFactory.newInstance();
Transformer transformer = tf.newTransformer();
DOMSource
source = new DOMSource(doc);
transformer.setOutputProperty(OutputKeys.ENCODING, "utf-8");
transformer.setOutputProperty(OutputKeys.INDENT, "no");
PrintWriter pw = new PrintWriter(out);
StreamResult result = new StreamResult(pw);
transformer.transform(source, result);
System.out.println("生成XML文件成功!");
} catch (ParserConfigurationException e) {
System.out.println(e.getMessage());
} catch (TransformerException e) {
System.out.println(e.getMessage());
}
}
這個就是創建上述xml文件的程序。使用的是dom來創建的。
其中的coordinate類如下：
public class coordinate {
private Integer id;
private String name;
private int x;
private int y;
public coordinate ()
{}
public coordinate
(String name ,int x,int y)
{
this.name = name;
this.x = x;
this.y = y;
}
public Integer getId() {
return id;
}
public void
setId(Integer id) {
this.id = id;
}
public String getName()
{
return name;
}
public void
setName(String name) {
this.name = name;
}
public int getX() {
return x;
}
public void setX(int x)
{
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y)
{
this.y = y;
}
@Override
public String toString()
{
// TODO Auto-generated method stub
return this.id+",name
"+this.name+" X
"+this.x+" Y
"+this.y+"\n";
}
}
我們只需要通過這樣一條語句就可以創建出需要的xml文件了。//list1中存放創建的內容
createXmlFile(list1,new FileOutputStream(new
File("/sdcard/data","c.xml")));
下面順便放上通過dom解析（讀取）xml文件的程序供大家參考：
public
List<coordinate>
XMLReader(InputStream inStream) throws Exception{
List<coordinate> persons=new
ArrayList<coordinate>();
DocumentBuilderFactory
factory=DocumentBuilderFactory.newInstance();
try{
DocumentBuilder
builder=factory.newDocumentBuilder();
Document document= builder.parse(inStream);
Element root=document.getDocumentElement();
NodeList
items=root.getElementsByTagName_r("_");
for(int
i=0;i<items.getLength();i++)
{
coordinate person=new coordinate();
Element personNode=(Element)items.item(i);
NodeList childsNodes =
personNode.getChildNodes();
for (int j = 0; j
< childsNodes.getLength();
j++)
{
Node node = (Node)
childsNodes.item(j);
if(node.getNodeType() ==
Node.ELEMENT_NODE)
{
Element childNode = (Element)
node;
if
("name".equals(childNode.getNodeName())) {
person.setName(childNode.getFirstChild().getNodeValue());
}
else if
("x".equals(childNode.getNodeName()))
{
person.setX(new
Short(childNode.getFirstChild().getNodeValue()));
}
else if
("y".equals(childNode.getNodeName()))
{
person.setY(new
Short(childNode.getFirstChild().getNodeValue()));
}
}
}
persons.add(person);
}
inStream.close();
}catch(Exception e){
e.printStackTrace();
}
return persons;
};