javax.xml xpath.XPath Factoryy provider-configuration file of Saxon-HE 9.3 中的语法错误

我在Mac OS X和Saxon-HE 9.3.0.5上使用Java SE 6。ServiceLoader 无法找到 的 Saxon 实现。javax.xml.xpath.XPathFactory

mac:test2 ludo$ java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03-383-11A511)
Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02-383, mixed mode)

查找过程第 3 点中的状态方法的 javadoc，用于本地化以下实现：newInstancejavax.xml.xpath.XPathFactory

类装入器被要求提供与资源目录 META-INF/services 中的 javax.xml xpath.XPathFactory 匹配的服务提供者配置文件。有关文件格式和解析规则，请参阅 JAR 文件规范。

JAR 文件规范的“服务提供程序”部分指出：

该文件应包含唯一具体提供程序类名称的换行符分隔列表。

但是，如果我提取saxon9he.jar文件并查看META-INF目录，我会看到：

mac:Java ludo$ mkdir test
mac:Java ludo$ cd test
mac:test ludo$ jar fx ../saxon9he.jar 
mac:test ludo$ cat META-INF/services/javax.xml.xpath.XPathFactory 
net.sf.saxon.xpath.XPathFactoryImpl
http\://java.sun.com/jaxp/xpath/dom:    net.sf.saxon.xpath.XPathFactoryImpl
http\://saxon.sf.net/jaxp/xpath/om:     net.sf.saxon.xpath.XPathFactoryImpl

第一行是正确的，但我不明白为什么有两行额外的行，看起来这些行给ServiceLoader带来了麻烦。我看到了一个测试示例的问题，我写了理解用于查找提供者的mecanism。我们可以看到 saxon9he.jar 在 CLASSPATH 中。

mac:services ludo$ java ServicesTest
CLASSPATH = ..., /Users/ludo/Library/Java/saxon9he.jar, ...
Service XPathFactory: java.util.ServiceLoader[javax.xml.xpath.XPathFactory]
ServiceConfigurationError: javax.xml.xpath.XPathFactory: jar:file:/Users/ludo/Library/Java/saxon9he.jar!/META-INF/services/javax.xml.xpath.XPathFactory:2: Illegal configuration-file syntax

感兴趣的是：

jar:file:/Users/ludo/Library/Java/saxon9he.jar!/META-INF/services/javax.xml.xpath.XPathFactory:2: Illegal configuration-file syntax

是Saxon的错误还是我的系统不支持的扩展语法？我能做些什么来解决这个问题？

请注意，如果我显式选择实现的类，我可以得到一个工厂。但我想使用服务机制。以下代码有效：

XPathFactory xpf = XPathFactory.newInstance(
  XPathFactory.DEFAULT_OBJECT_MODEL_URI,
  "net.sf.saxon.xpath.XPathFactoryImpl",
  ClassLoader.getSystemClassLoader());

我在下面添加了整个Java测试程序。

import java.net.URL;
import java.net.URLClassLoader;
import java.util.Iterator;
import java.util.ServiceConfigurationError;
import java.util.ServiceLoader;
import javax.xml.xpath.XPathFactory;

public class ServicesTest {
    public static String getClasspathString() {
        StringBuilder classpath = new StringBuilder();
        ClassLoader classLoader = ClassLoader.getSystemClassLoader();
        URL[] urls = ((URLClassLoader) classLoader).getURLs();
        for (int i = 0; i < urls.length - 1; i++) {
            classpath.append(urls[i].getFile()).append(", ");
        }
        if (urls.length > 0) {
            classpath.append(urls[urls.length - 1].getFile());
        }

        return classpath.toString();
    }

    public static void availableProviders(ServiceLoader sl) {
        Iterator it = sl.iterator();
        int index = 0;
        for (;;) {
            try {
                if (!it.hasNext()) {
                    break;
                }
                index++;
                Object o = it.next();
                System.out.printf("%03d Concrete class name: %s\n", index, o.getClass().getName());
            } catch (ServiceConfigurationError e) {
                System.err.printf("ServiceConfigurationError: %s\n", e.getMessage());
            }
        }
    }

    public static void main(String[] args) {
        System.out.printf("CLASSPATH = %s\n", getClasspathString());
        System.out.println();

        ServiceLoader<XPathFactory> slXPathFactory = ServiceLoader.load(XPathFactory.class);
        System.out.printf("Service XPathFactory: %s\n", slXPathFactory.toString());
        availableProviders(slXPathFactory);
    }
}