理解osworkflow.XML：
加载osworkflow.xml过程:
1)DefaultConfiguration中,在load方法中调用getInputStream()以获取系统的osworkflow.xml文件
在getInputStream方法中：
protected InputStream getInputStream(URL url) {
InputStream is = null;
if (url != null) {
try {
is = url.openStream();
} catch (Exception ex) {
}
}
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
if (is == null) {
try {
is = classLoader.getResourceAsStream("osworkflow.xml");
} catch (Exception e) {
}
}
if (is == null) {
try {
is = classLoader.getResourceAsStream("/osworkflow.xml");
} catch (Exception e) {
}
}
