[英]XML Schema Validation in Android
我已經創建了一個XML,我想使用模式進行驗證,即XSD文件,但是如果我沒有記錯的話,Android不會提供相同的直接類.........並且有一個名為jaxp1.3
的外部jar jaxp1.3
哪個不允許我編譯代碼,是因為台式機和android的字節碼不同? 里面有類工廠和驗證器,它們做驗證工作……......還有其他選擇嗎? 任何幫助將不勝感激.....拼命尋找ans ..........
這是Google 在這里發布的一個已知問題
解決方案是使用Apache Xerces移植到Android。 有一個項目在這里
您必須執行svn chekout並將proyect導出到jar文件中,以用作android proyect中的庫。
實例SchemaFactory的代碼稍有變化。 我給你看一個例子:
import mf.javax.xml.validation.Schema;
import mf.javax.xml.validation.SchemaFactory;
import mf.javax.xml.validation.Validator;
import mf.org.apache.xerces.jaxp.validation.XMLSchemaFactory;
SchemaFactory factory = new XMLSchemaFactory();
Schema esquema = factory.newSchema(".../file.xsd");
@iOSDev,我必須使用Xerces-for-Android進行驗證。 以下是我為使其與程序一起工作所做的摘要:
Android確實支持我們可以使用的某些程序包,我基於以下程序創建了xml驗證實用程序: http : //docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html
我最初的沙箱測試使用Java相當順利,然后我嘗試將其移植到Dalvik,發現我的代碼無法正常工作。 Dalvik不支持某些功能,因此我進行了一些修改。
我找到了針對Android的xerces的引用,因此修改了我的沙盒測試( 以下內容不適用於android,之后的示例適用 ):
import java.io.File;
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Source;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
import org.w3c.dom.Document;
/**
* A Utility to help with xml communication validation.
*/
public class XmlUtil {
/**
* Validation method.
* Base code/example from: http://docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html
*
* @param xmlFilePath The xml file we are trying to validate.
* @param xmlSchemaFilePath The schema file we are using for the validation. This method assumes the schema file is valid.
* @return True if valid, false if not valid or bad parse.
*/
public static boolean validate(String xmlFilePath, String xmlSchemaFilePath) {
// parse an XML document into a DOM tree
DocumentBuilder parser = null;
Document document;
// Try the validation, we assume that if there are any issues with the validation
// process that the input is invalid.
try {
// validate the DOM tree
parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
document = parser.parse(new File(xmlFilePath));
// create a SchemaFactory capable of understanding WXS schemas
SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
// load a WXS schema, represented by a Schema instance
Source schemaFile = new StreamSource(new File(xmlSchemaFilePath));
Schema schema = factory.newSchema(schemaFile);
// create a Validator instance, which can be used to validate an instance document
Validator validator = schema.newValidator();
validator.validate(new DOMSource(document));
} catch (Exception e) {
// Catches: SAXException, ParserConfigurationException, and IOException.
return false;
}
return true;
}
}
上面的代碼必須進行一些修改才能與適用於Android的xerces( http://gc.codehum.com/p/xerces-for-android/ )一起使用。 您需要SVN才能獲得項目,以下是一些嬰兒床說明:
download xerces-for-android
download silk svn (for windows users) from http://www.sliksvn.com/en/download
install silk svn (I did complete install)
Once the install is complete, you should have svn in your system path.
Test by typing "svn" from the command line.
I went to my desktop then downloaded the xerces project by:
svn checkout http://xerces-for-android.googlecode.com/svn/trunk/ xerces-for-android-read-only
You should then have a new folder on your desktop called xerces-for-android-read-only
使用上面的jar(最終我將其放入一個jar中,只需將其直接復制到我的源代碼中即可進行快速測試。如果您希望這樣做,則可以使用Ant( http://ant.apache .org / manual / using.html )),我可以通過以下操作來進行xml驗證:
import java.io.File;
import java.io.IOException;
import mf.javax.xml.transform.Source;
import mf.javax.xml.transform.stream.StreamSource;
import mf.javax.xml.validation.Schema;
import mf.javax.xml.validation.SchemaFactory;
import mf.javax.xml.validation.Validator;
import mf.org.apache.xerces.jaxp.validation.XMLSchemaFactory;
import org.xml.sax.SAXException;
/**
* A Utility to help with xml communication validation.
*/public class XmlUtil {
/**
* Validation method.
*
* @param xmlFilePath The xml file we are trying to validate.
* @param xmlSchemaFilePath The schema file we are using for the validation. This method assumes the schema file is valid.
* @return True if valid, false if not valid or bad parse or exception/error during parse.
*/
public static boolean validate(String xmlFilePath, String xmlSchemaFilePath) {
// Try the validation, we assume that if there are any issues with the validation
// process that the input is invalid.
try {
SchemaFactory factory = new XMLSchemaFactory();
Source schemaFile = new StreamSource(new File(xmlSchemaFilePath));
Source xmlSource = new StreamSource(new File(xmlFilePath));
Schema schema = factory.newSchema(schemaFile);
Validator validator = schema.newValidator();
validator.validate(xmlSource);
} catch (SAXException e) {
return false;
} catch (IOException e) {
return false;
} catch (Exception e) {
// Catches everything beyond: SAXException, and IOException.
e.printStackTrace();
return false;
} catch (Error e) {
// Needed this for debugging when I was having issues with my 1st set of code.
e.printStackTrace();
return false;
}
return true;
}
}
一些注意事項:
為了創建文件,我制作了一個簡單的文件實用程序來將字符串寫入文件:
public static void createFileFromString(String fileText, String fileName) {
try {
File file = new File(fileName);
BufferedWriter output = new BufferedWriter(new FileWriter(file));
output.write(fileText);
output.close();
} catch ( IOException e ) {
e.printStackTrace();
}
}
我還需要寫一個我可以訪問的區域,所以我使用了:
String path = this.getActivity().getPackageManager().getPackageInfo(getPackageName(), 0).applicationInfo.dataDir;
有點黑,它的工作原理。 我敢肯定,這樣做有更簡潔的方法,但是我認為我會分享自己的成功,因為我沒有發現任何好的例子。
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