经过查看配置类Configration源代码发现，类加载器会使用当前程序默认的Classloader
public Configuration(boolean loadDefaults) {
this.quietmode = true;
this.allowNullValueProperties = false;
this.resources = new ArrayList();
this.finalParameters = Collections.newSetFromMap(new ConcurrentHashMap());
this.loadDefaults = true;
this.classLoader = Thread.currentThread().getContextClassLoader();
if (this.classLoader == null) {
this.classLoader = Configuration.class.getClassLoader();
}
this.loadDefaults = loadDefaults;
this.updatingResource = new ConcurrentHashMap();
Class var2 = Configuration.class;
synchronized(Configuration.class) {
REGISTRY.put(this, (Object)null);
}
}
而我在kettle开发时使用的是插件形式，加载类时读取了kettle默认的根目录，导致无法加载插件的hdfs相关类。
解决方式：初始化定义自己的classloader:
Configuration hdfsConf = new Configuration();
hdfsConf.setClassLoader(this.getClass().getClassLoader());