An easy way to merge multiple XML files-External entity references

The following example merges the file Order1.xml with the file order2.xml into a single file through an external entity reference Directory.xml

Listing 1. XML document Order1.xml to be merged:

<?xml version= "1.0" encoding= "GB2312"?>

<order>
  <item>
    <itemnumber>ksu-0384</itemnumber>
    <DESCRIPTION>LCD LCD monitor </description>
    <quantity>1</ Quantity>
    <price>358.00</price>
  </item>
     <item>
    <itemnumber>ksu-0511</itemnumber>
    <description> speaker </description>
    <quantity>1</quantity>
     <price>16.50</price>
  </item>
    <item>
    <itemnumber>ksu-7710</itemnumber>
    <description> Mouse < /description>
    <quantity>1</quantity>
    <price> 8.50</price>
  </item>
</order>

Listing 2. XML document to be merged order2.xml:

<?xml version= "1.0" encoding= "GB2312"?>

<order>
  <item>
    <itemnumber>ksu-0652</itemnumber>
    <description> threesome keyboard </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> Maxtor HDD </description>
    <quantity>1</quantity>
    < Price>850.00</price>
  </item>
</order>

Listing 3. Output document Directory.xml, the boldface section is the entity declaration and its reference:

<?xml version= "1.0"?>
<! DOCTYPE Directory [
<! ENTITY disclaimer1 SYSTEM "./order1.xml" >
<! ENTITY disclaimer2 SYSTEM "./order2.xml" >
]>
<directory>
&disclaimer1;
&disclaimer2;
</directory>

When an XML 1.0-compliant processor reads a document, it expands the entity to replace the reference with its contents, so the complete document looks like the following.

Listing 4. Document display with extended entities (in IE6):

<?xml version= "1.0"?>
<! DOCTYPE directory (View Source for full DOCTYPE ...) >
-<directory>
-<order>
-<item>
<itemNumber>ksu-0384</itemNumber>
&LT;DESCRIPTION&GT;LCD LCD Monitor </description>
<quantity>1</quantity>
<price>358.00</price>
</item>
-<item>
<itemNumber>ksu-0511</itemNumber>
<description> Speaker </description>
<quantity>1</quantity>
<price>16.50</price>
</item>
-<item>
<itemNumber>ksu-7710</itemNumber>
<description> Mouse </description>
<quantity>1</quantity>
<price>8.50</price>
</item>
</order>
-<order>
-<item>
<itemNumber>ksu-0652</itemNumber>
<description> Threesome Keyboard </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> Maxtor HDD </description>
<quantity>1</quantity>
<price>850.00</price>
</item>
</order>
</directory>