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我有以下XML：切割與JAXB一個XML
<Package>
<PackageHeader>
<name>External Vendor File</name>
<description>External vendor file for some purpose</description>
<version>3.141694baR3</version>
</PackageHeader>
<PackageBody>
<Characteristic id="1">
<Size>
<value>1.68</value>
<scale>Meters</scale>
<comment>Size can vary, depending on temperature</comment>
</Size>
<Weight>
<value>9</value>
<scale>M*Tons</scale>
<comment>His mama is so fat, we had to use another scale</comment>
</Weight>
<rating>
<ratingCompany>ISO</ratingCompany>
<rating:details xmlns:rating="http://www.w3schools.com/ratingDetails">
<rating:value companyDepartment="Finance">A</rating:value>
<rating:expirationDate update="1/12/2010">1/1/2014</rating:expirationDate>
<rating:comment userID="z94234">You're not Silvia.</rating:comment>
<rating:comment userID="r24942">You're one of the Kung-Fu Creatures On The Rampage</rating:comment>
<rating:comment userID="i77880">TWO!</rating:comment>
<rating:priority>3</rating:priority>
</rating:details>
</rating>
</Characteristic>
<Characteristic id="2">
<Size/>
<Weight/>
<rating/>
</Characteristic>
...
<Characteristic id="n"/>
</PackageBody>
</Package>
而且Java代碼：
public class XMLTest {
public static void main(String[] args) throws Exception {
Package currentPackage = new Package();
Package sourcePackage = new Package();
int totalCharacteristics;
PackageBody currentPackageBody = new PackageBody();
Characteristic currentCharacteristic = new Characteristic();
rating currentRating = new rating();
FileInputStream fis = new FileInputStream("sourceFile.xml");
JAXBContext myCurrentContext = JAXBContext.newInstance(Package.class);
Marshaller m = myCurrentContext.createMarshaller();
Unmarshaller um = myCurrentContext.createUnmarshaller();
sourcePackage = (Package)um.unmarshal(fis);
currentPackage.setPackageHeader(sourcePackage.getPackageHeader());
totalCharacteristics = sourcePackage.getPackageBody().getCharacteristics().size();
for (int i = 0; i < totalCharacteristics; i++)
{
currentRating = sourcePackage.getPackageBody().getCharacteristics().get(i).getrating();
}
currentCharacteristic.setrating(currentRating);
currentPackageBody.getCharacteristics().add(currentCharacteristic);
currentPackage.setPackageBody(currentPackageBody);
m.marshal(currentPackage, new File("targetFile.xml"));
fis.close();
}
}
這使我的下一個XML：
<Package>
<PackageHeader>
<name>External Vendor File</name>
<description>External vendor file for some purpose</description>
<version>3.141694baR3</version>
</PackageHeader>
<PackageBody>
<Characteristic id="1">
<rating>
<ratingCompany>ISO</ratingCompany>
<rating:details xmlns:rating="http://www.w3schools.com/ratingDetails">
<rating:value companyDepartment="Finance">A</rating:value>
<rating:expirationDate update="1/12/2010">1/1/2014</rating:expirationDate>
<rating:comment userID="z94234">You're not Silvia.</rating:comment>
<rating:comment userID="r24942">You're one of the Kung-Fu Creatures On The Rampage</rating:comment>
<rating:comment userID="i77880">TWO!</rating:comment>
<rating:priority>3</rating:priority>
</rating:details>
</rating>
</Characteristic>
<Characteristic id="2">
<rating/>
</Characteristic>
...
<Characteristic id="n"/>
</PackageBody>
</Package>
這是我需要的：
<Package>
<PackageHeader>
<name>External Vendor File</name>
<description>External vendor file for some purpose</description>
<version>3.141694baR3</version>
</PackageHeader>
<PackageBody>
<Characteristic>
<rating id="1">
<ratingCompany>ISO</ratingCompany>
<rating:details xmlns:rating="http://www.w3schools.com/ratingDetails">
<rating:comment userID="z94234">You're not Silvia.</rating:comment>
<rating:comment userID="r24942">You're one of the Kung-Fu Creatures On The Rampage</rating:comment>
<rating:comment userID="i77880">TWO!</rating:comment>
<rating:priority>3</rating:priority>
</rating:details>
</rating>
</Characteristic>
<Characteristic>
<rating id="2"/>
</Characteristic>
...
<Characteristic/>
</PackageBody>
</Package>
但我有幾個問題：
我怎麼可能實現的方式來讀取一個文件4GBs？ （例如，用StAX讀取它）。
如果我想過濾從源到目標的一些標籤（如最後一個xml），我必須將它們逐一分配給targetFile嗎？是否有任何迭代器可能允許我遍歷所有子節點並分配它們？
如果sourceFile發生變化，我是否需要重新運行xjc並重新編譯整個項目？
謝謝。