针对 XSD 架构的 Java XML 验证

Java XML validation against XSD Schema

提问by Becky

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());
    }
}

But this returns an error saying: Exception in thread "main" java.lang.IllegalArgumentException: No SchemaFactory that implements the schema language specified by: http://www.w3.org/2001/XMLSchema-instance could be loaded

但这会返回一个错误，指出：线程“main”中的异常 java.lang.IllegalArgumentException: No SchemaFactory that implementation the schema language specified by: http://www.w3.org/2001/XMLSchema-instance can be loaded

Is this a problem with my code or with the actual xsd file?

这是我的代码或实际 xsd 文件的问题吗？

采纳答案by brabster

That error means that your installed Java doesn't have any classes that can parse XMLSchema files, so it's not a problem with the schema or your code.

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

I'm pretty sure recent JREs have the appropriate classes by default, so can you get us the output of java -version?

我很确定默认情况下最近的 JRE 具有适当的类，所以你能得到我们的输出java -version吗？

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Update:

更新：

You're using the wrong XMLContants string. You want: XMLConstants.W3C_XML_SCHEMA_NS_URI

您使用了错误的 XMLContants 字符串。你要：XMLConstants.W3C_XML_SCHEMA_NS_URI

回答by James Oravec

Those files are based on the underlying system. I had the same issue when I was programming a project for Android. I found that I had to use Xerces-for-Android to solve my problem.

这些文件基于底层系统。我在为 Android 编写项目时遇到了同样的问题。我发现我不得不使用 Xerces-for-Android 来解决我的问题。

The following worked for me for validation on Android, if your code relates to Android perhaps it will help, if it doesn't then perhaps the approach will help you with your underlying system:

以下为我在 Android 上的验证工作，如果您的代码与 Android 相关，它可能会有所帮助，如果没有，那么该方法可能会帮助您使用底层系统：

1. Create a validation utility.
2. Get both the xml and xsd into file on the android OS and use the validation utility against it.
3. Use Xerces-For-Android to do the validation.

1. 创建验证实用程序。
2. 将 xml 和 xsd 都获取到 android 操作系统上的文件中，并针对它使用验证实用程序。
3. 使用 Xerces-For-Android 进行验证。

Android does support some packages which we can use, I created my xml validation utility based on: http://docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html

Android 确实支持我们可以使用的一些包，我创建了我的 xml 验证实用程序基于：http: //docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html

My initial sandbox testing was pretty smooth with java, then I tried to port it over to Dalvik and found that my code did not work. Some things just aren't supported the same with Dalvik, so I made some modifications.

我最初的沙箱测试用 java 很顺利，然后我尝试将它移植到 Dalvik，发现我的代码不起作用。有些东西与 Dalvik 不一样，所以我做了一些修改。

I found a reference to xerces for android, so I modified my sandbox test of (the following doesn't work with android, the example after this does):

我找到了对 android 的 xerces 的引用，所以我修改了我的沙箱测试（以下不适用于 android，此后的示例适用）：

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;
    }
}

The above code had to be modified some to work with xerces for android (http://gc.codehum.com/p/xerces-for-android/). You need SVN to get the project, the following are some crib notes:

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。你需要SVN来获取项目，以下是一些crib笔记：

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

With the above jar (Eventually I'll make it into a jar, just copied it directly into my source for quick testing. If you wish to do the same, you can making the jar quickly with Ant (http://ant.apache.org/manual/using.html)), I was able to get the following to work for my xml validation:

用上面的jar（最终我会做成一个jar，直接复制到我的源代码中进行快速测试。如果你也想这样做，你可以用Ant（http://ant.apache）快速制作这个jar .org/manual/using.html))，我能够得到以下内容用于我的 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;
    }
}

Some Side Notes:

一些旁注：

For creating the files, I made a simple file utility to write string to files:

为了创建文件，我制作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();
    }
}

I also needed to write to an area that I had access to, so I made use of:

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;   

A little hackish, it works. I'm sure there is a more succinct way of doing this, however I figured I'd share my success, as there weren't any good examples that I found.

有点hackish，它有效。我确信有一种更简洁的方法可以做到这一点，但是我想我会分享我的成功，因为我没有找到任何好的例子。