Weka Python封装器加载器

Question

我在Mac OS X 10.9.4上安装了weka的Python包装器。然后我尝试运行示例代码：

import weka.core.jvm as jvm
jvm.start()

from weka.core.converters import Loader
l = Loader("weka.core.converters.ArffLoader")
d = l.load_file("X.arff")

d.set_class_index(d.num_attributes() - 1)
print(d)

结果出现了以下错误：

Failed to get class weka/core/converters/ArffLoader
Exception in thread "Thread-2" java.lang.NoClassDefFoundError: weka/core/converters/ArffLoader
Failed to instantiate weka.core.converters.ArffLoader/weka/core/converters/ArffLoader: weka/core/converters/ArffLoader
Caused by: java.lang.ClassNotFoundException: weka.core.converters.ArffLoader
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Traceback (most recent call last):
  File "/Users/hani/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2883, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-5-d835d9d560d2>", line 2, in <module>
    l = Loader("weka.core.converters.ArffLoader")
  File "/Users/hani/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/python_weka_wrapper-0.1.10-py2.7.egg/weka/core/converters.py", line 40, in __init__
    self.enforce_type(jobject, "weka.core.converters.Loader")
  File "/Users/hani/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/python_weka_wrapper-0.1.10-py2.7.egg/weka/core/classes.py", line 113, in enforce_type
    raise TypeError("Object does not implement or subclass " + intf_or_class + "!")
TypeError: Object does not implement or subclass weka.core.converters.Loader!

经过一番折腾，我发现通过使用os.chdir把工作目录设置为python-weka-wrapper文件夹，可以在某些环境中解决这个问题，但并不是所有环境都能解决（比如在pycharm中用这个方法就不管用）。有没有什么办法可以解决这个问题呢？

Answer 1

看起来，使用weka的jar文件路径来调用jvm可以解决这个问题：

jvm.start(class_path=['/some/where/python-weka-wrapper.jar', 
'/some/where/weka.jar'])

感谢Peter Reutemann的这个回复。