Question

private void validateXML(DOMSource source) throws Exception {
    URL schemaFile = new URL("http://www.csc.liv.ac.uk/~valli/modules.xsd");
    SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_INSTANCE_NS_URI);
    Schema schema = schemaFactory.newSchema(schemaFile);

    Validator validator = schema.newValidator();
    DOMResult result = new DOMResult();
    try {
        validator.validate(source, result); 
        System.out.println("is valid");
    } catch (SAXException e) {
        System.out.println("not valid because " + e.getLocalizedMessage());
    }
}

但是这会返回一个错误说：线程“main”中的异常java.lang.IllegalArgumentException：没有实现由http://www.w3.org/2001/XMLSchema -instance指定的模式语言的SchemaFactory

这是我的代码还是实际的xsd文件的问题？

Answer 1

该错误意味着您安装的Java没有任何可以解析XMLSchema文件的类，因此它不是架构或代码的问题。

我很确定最近的JRE默认有相应的类，所以你能告诉我们java -version的输出吗？

更新

您使用的是错误的XMLContants字符串。你想要：XMLConstants.W3C_XML_SCHEMA_NS_URI

Answer 2

这些文件基于底层系统。我在编写Android项目时遇到了同样的问题。我发现我必须使用Xerces-for-Android来解决我的问题。

以下是我在Android上进行验证的方法，如果你的代码与Android有关，也许它会有所帮助，如果它没有，那么这种方法可能会对你的底层系统有所帮助：

创建验证实用程序。
在Android操作系统上同时获取xml和xsd文件并对其使用验证实用程序。
使用Xerces-For-Android进行验证。

Android确实支持我们可以使用的一些软件包，我根据以下内容创建了我的xml验证工具：http://docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html

我最初的沙盒测试使用java非常顺利，然后我尝试将其移植到Dalvik并发现我的代码无效。有些事情与Dalvik不相同，所以我做了一些修改。

我找到了一个对xerces for android的引用，所以我修改了我的沙箱测试（以下不适用于android，这个例子之后的例子）：

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;
    }
}

上面的代码必须修改一些才能与xerces for android（http://gc.codehum.com/p/xerces-for-android/）一起使用。您需要SVN才能获得该项目，以下是一些小册子：

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（最后我会把它变成一个jar，只需将它直接复制到我的源代码中进行快速测试。如果你想这样做，你可以用Ant快速制作jar（{{3} }），我能够得到以下代码来进行我的xml验证：

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;
    }
}

一些备注：

为了创建文件，我创建了一个简单的文件实用程序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();
    }
}

我还需要写一个我可以访问的区域，所以我使用了：

String path = this.getActivity().getPackageManager().getPackageInfo(getPackageName(), 0).applicationInfo.dataDir;

有点hackish，它的确有效。我确信有一种更简洁的方式可以做到这一点，但我想我会分享我的成功，因为我找不到任何好的例子。

针对XSD架构的Java XML验证

2 个答案: