下面的例子通过外部实体引用,将文件order1.xml与文件order2.xml合并为一个文件directory.xml清单1. 要合并的xml文档order1.xml:<?xml version="1.0" encoding="GB2312"?><order>
<item>
<itemNumber>ksu-0384</itemNumber>
<description>LCD液晶显示器</description>
<quantity>1</quantity>
<price>358.00</price>
</item>
<item>
<itemNumber>ksu-0511</itemNumber>
<description>音箱</description>
<quantity>1</quantity>
<price>16.50</price>
</item>
<item>
<itemNumber>ksu-7710</itemNumber>
<description>鼠标</description>
<quantity>1</quantity>
<price>8.50</price>
</item>
</order>清单2. 要合并的xml文档order2.xml:<?xml version="1.0" encoding="GB2312"?><order>
<item>
<itemNumber>ksu-0652</itemNumber>
<description>双飞燕键盘</description>
<quantity>1</quantity>
<price>35.00</price>
</item>
<item>
<itemNumber>ksu-7720</itemNumber>
<description>intel CPU</description>
<quantity>1</quantity>
<price>1650.00</price>
</item>
<item>
<itemNumber>ksu-7010</itemNumber>
<description>迈拓硬盘</description>
<quantity>1</quantity>
<price>850.00</price>
</item>
</order>清单3. 输出文档directory.xml,黑体字部分为实体声明及其引用:<?xml version="1.0"?>
<!DOCTYPE directory [
<!ENTITY disclaimer1 SYSTEM "./order1.xml">
<!ENTITY disclaimer2 SYSTEM "./order2.xml">
]>
<directory>
&disclaimer1;
&disclaimer2;
</directory>当符合 XML 1.0 的处理器读取文档时,就会扩展实体,用它的内容代替引用,因此完整的文档如下所示。清单4. 带有扩展实体的文档显示(IE6中): <?xml version="1.0" ?>
<!DOCTYPE directory (View Source for full doctype...)>
- <directory>
- <order>
- <item>
<itemNumber>ksu-0384</itemNumber>
<description>LCD液晶显示器</description>
<quantity>1</quantity>
<price>358.00</price>
</item>
- <item>
<itemNumber>ksu-0511</itemNumber>
<description>音箱</description>
<quantity>1</quantity>
<price>16.50</price>
</item>
- <item>
<itemNumber>ksu-7710</itemNumber>
<description>鼠标</description>
<quantity>1</quantity>
<price>8.50</price>
</item>
</order>
- <order>
- <item>
<itemNumber>ksu-0652</itemNumber>
<description>双飞燕键盘</description>
<quantity>1</quantity>
<price>35.00</price>
</item>
- <item>
<itemNumber>ksu-7720</itemNumber>
<description>intel CPU</description>
<quantity>1</quantity>
<price>1650.00</price>
</item>
- <item>
<itemNumber>ksu-7010</itemNumber>
<description>迈拓硬盘</description>
<quantity>1</quantity>
<price>850.00</price>
</item>
</order>
</directory>
<item>
<itemNumber>ksu-0384</itemNumber>
<description>LCD液晶显示器</description>
<quantity>1</quantity>
<price>358.00</price>
</item>
<item>
<itemNumber>ksu-0511</itemNumber>
<description>音箱</description>
<quantity>1</quantity>
<price>16.50</price>
</item>
<item>
<itemNumber>ksu-7710</itemNumber>
<description>鼠标</description>
<quantity>1</quantity>
<price>8.50</price>
</item>
</order>清单2. 要合并的xml文档order2.xml:<?xml version="1.0" encoding="GB2312"?><order>
<item>
<itemNumber>ksu-0652</itemNumber>
<description>双飞燕键盘</description>
<quantity>1</quantity>
<price>35.00</price>
</item>
<item>
<itemNumber>ksu-7720</itemNumber>
<description>intel CPU</description>
<quantity>1</quantity>
<price>1650.00</price>
</item>
<item>
<itemNumber>ksu-7010</itemNumber>
<description>迈拓硬盘</description>
<quantity>1</quantity>
<price>850.00</price>
</item>
</order>清单3. 输出文档directory.xml,黑体字部分为实体声明及其引用:<?xml version="1.0"?>
<!DOCTYPE directory [
<!ENTITY disclaimer1 SYSTEM "./order1.xml">
<!ENTITY disclaimer2 SYSTEM "./order2.xml">
]>
<directory>
&disclaimer1;
&disclaimer2;
</directory>当符合 XML 1.0 的处理器读取文档时,就会扩展实体,用它的内容代替引用,因此完整的文档如下所示。清单4. 带有扩展实体的文档显示(IE6中): <?xml version="1.0" ?>
<!DOCTYPE directory (View Source for full doctype...)>
- <directory>
- <order>
- <item>
<itemNumber>ksu-0384</itemNumber>
<description>LCD液晶显示器</description>
<quantity>1</quantity>
<price>358.00</price>
</item>
- <item>
<itemNumber>ksu-0511</itemNumber>
<description>音箱</description>
<quantity>1</quantity>
<price>16.50</price>
</item>
- <item>
<itemNumber>ksu-7710</itemNumber>
<description>鼠标</description>
<quantity>1</quantity>
<price>8.50</price>
</item>
</order>
- <order>
- <item>
<itemNumber>ksu-0652</itemNumber>
<description>双飞燕键盘</description>
<quantity>1</quantity>
<price>35.00</price>
</item>
- <item>
<itemNumber>ksu-7720</itemNumber>
<description>intel CPU</description>
<quantity>1</quantity>
<price>1650.00</price>
</item>
- <item>
<itemNumber>ksu-7010</itemNumber>
<description>迈拓硬盘</description>
<quantity>1</quantity>
<price>850.00</price>
</item>
</order>
</directory>
Private Boolean is Merging (String mainFileName, String sub Filename) throws Exception {
Boolean isOver = false;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
Document Builder db = null;
Try {
Db = dbf.newDocumentBuilder ();
} Catch (ParserConfigurationException pce) {
System.err.println(pce); //出现异常时,输出异常信息
}
Document doc_main = null,doc_vice = null;
//获取两个XML文件的Document。
Try {
Doc_main = db.parse (mainFileName);
Doc_vice = db.parse (sub Filename);
} Catch (DOM Exception dom) {
System.err.println (dom.getMessage ());
} Catch (Exception ioe) {
System.err.println (ioe);
}
//获取两个文件的根元素。
Element root_main = doc_main.getDocumentElement ();
Element root_vice = doc_vice.getDocumentElement ();
//下面添加被合并文件根节点下的每个元素
Novelist message Items = root_vice.getChildNodes ();
Int item_number = messageItems.getLength ();
//如果去掉根节点下的第一个元素,比如<所属管理系统> ,那么i从3开始。否则i从1开始。
For (int i=1; i < item_number; i=i+2 ) {
//调用dupliate(),依次复制被合并XML文档中根节点下的元素。
Element messageItem = (Element) messageItems.item (i);
IsOver = dupliate (doc_main, root_main, messageItem);
}
//调用 write To(),将合并得到的Document写入目标XML文档。
Boolean isWritten = write To (doc_main, mainFileName);
Return isOver && isWritten;
}//主函数
Public static void main (String [] args) throws Exception {
Boolean is done = is Merging ("D:/a.xml","D:/b.xml");
If (is Done) System.out.println ("XML files have been merged.");
Else System.out.println ("XML files have NOT been merged.");
}
}
Boolean is done = false;
String son_name = son.getNodeName ();
Element sub ITEM = doc_dup.createElement (son_name);
//复制节点的属性
If (son.hasAttributes ()){
NamedNodeMap attributes = son.getAttributes ();
For (int i=0; i < attributes.getLength () ; i ++){
String attribute_name = attributes. Item (i). GetNodeName ();
String attribute_value = attributes. Item (i). GetNodeValue ();
SubITEM.setAttribute (attribute_name, attribute_value);
}
}
Father.appendChild (sub ITEM);
//复制节点的值
Text value son = (Text) son.getFirstChild ();
String nodevalue_root = "";
If (value_son! = null && value_son.getLength () > 0) nodevalue_root = (String) value_son.getNodeValue ();
Text valuenode_root = null;
If ((nodevalue_root! = null)&&(nodevalue_root.length () > 0)) valuenode_root = doc_dup.createTextNode (nodevalue_root);
If (valuenode_root! = null && valuenode_root.getLength () > 0) subITEM.appendChild (valuenode_root);
//复制子结点
Novelist sub_messageItems = son.getChildNodes ();
int sub_item_number = sub_messageItems.getLength();
if (sub_item_number < 2){
//如果没有子节点,则返回
Is done = true;
}
Else {
For (int j = 1; j < sub_item_number; j=j+2) {
//如果有子节点,则递归调用本方法
Element sub_messageItem = (Element) sub_messageItems.item (j);
Is done = dupliate (doc_dup, subITEM, sub_messageItem);
}
}
Return is done;
}Private Boolean write To (Document doc, String fileName) throws Exception {
Boolean isOver = false;
DOM Source doms = new DOM Source (doc);
File f = new File (fileName);
Stream Result sr = new Stream Result (f);
Try
{
Transformer Factory tf=TransformerFactory.newInstance ();
Transformer t=tf.newTransformer ();
Properties properties = t.getOutputProperties ();
Properties.setProperty (OutputKeys.ENCODING,"GB2312");
T.setOutputProperties (properties);
T.transform (doms, sr);
IsOver = true;
}
Catch (TransformerConfigurationException tce)
{
Tce.printStackTrace ();
}
Catch (Transformer Exception te)
{
Te.printStackTrace ();
}
Return isOver;
}