我创建了一个XML
文件,同时有一个XSD
文件,我需要使用这个模式验证XML文件。请问是否可以提供一个示例来进行验证?还有,在我的项目中应该把XSD文件放在哪里,以便能够使用该模式进行验证。
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");
这可能帮助不大,但据我所知,Android平台是一个有些受限的Java环境。主要问题是一些API应该是可用的,特别是javax.xml.validation(JDK 1.5及以上版本的一部分!)却不在其中。
因此,您可能需要包含比非截肢Java平台更多的jar文件。 此外,由于黑名单/白名单问题,可能会有添加标准API的限制(这是Google AppEngine的一个大问题,而Android早于它,因此存在类似的挑战)。
除此之外,我建议尝试使用捆绑的XML解析器Xerces来使用javax.xml.validation。有无数的如何操作文档可以参考。
经过阅读许多帖子和尝试各种不同的方法,我终于成功地使用Xerces-for-Android使一切正常运转,并为大家精心记录下了这个过程……希望能帮到您 :)
以下是对我有效的处理方式:
Android确实支持一些我们可以使用的包,我根据以下内容创建了自己的xml验证工具:http://docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html
我的最初的沙盒测试在Java中非常顺利,然后我尝试将其移植到Dalvik上,但发现我的代码无法运行。有些东西在Dalvik上的支持并不相同,因此我进行了一些修改。
我找到了有关xerces for android的参考资料,所以我修改了我的沙箱测试(以下内容无法在android上运行,下面的示例可以):
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;
}
}
上述代码需要进行一些修改才能与适用于Android的Xerces(http://gc.codehum.com/p/xerces-for-android/)一起使用。您需要使用SVN获取项目,以下是一些提示:
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
使用上述的jar文件(最终我会将其制作成jar文件,只是为了快速测试,我直接将其复制到我的源代码中。如果您希望做同样的事情,可以使用Ant快速制作jar文件(http://ant.apache.org/manual/using.html)),我能够让以下内容在我的xml验证中正常工作:
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;
}
}
一些侧记:
为了创建文件,我制作了一个简单的文件工具来将字符串写入文件:
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();
}
}
我也需要写入我可以访问的区域,所以我使用了:
String path = this.getActivity().getPackageManager().getPackageInfo(getPackageName(), 0).applicationInfo.dataDir;