Jython的os.name问题

下面的这段脚本是在python中调用java来运行ant命令, 可以在Jython中却运行失败, 找不到ant的Main类, 什么原因呢?

#!/usr/bin/python
"""

 runant.py
 Assumptions:

 - the "java" executable/script is on the command path
 - ANT_HOME has been set
"""
import os, os.path, string, sys

# Change it to 1 to get extra debug information
debug = 0

#######################################################################
#
# check to make sure environment is setup
#
if not os.environ.has_key('ANT_HOME'):
	print '\n\nANT_HOME *MUST* be set!\n\n'
	sys.exit(1)
else:
	ANT_HOME = os.environ['ANT_HOME']

if not os.environ.has_key('JAVACMD'):
	JAVACMD = 'java'
else:
	JAVACMD = os.environ['JAVACMD']

# Sets the separator char for CLASSPATH
SEPARATOR = ':'
if os.name == 'dos' or os.name == 'nt':
	SEPARATOR = ';'

# Build up standard classpath
localpath = ''
if os.environ.has_key('CLASSPATH'):
	localpath = os.environ['CLASSPATH']
else:
	if debug:
		print 'Warning: no initial classpath\n'

# Add jar files
LIBDIR = os.path.join(ANT_HOME, 'lib')
jarfiles = []
for file in os.listdir(LIBDIR):
	if file[-4:] == '.jar':
		jarfiles.append(os.path.join(LIBDIR,file))
if debug:
	print 'Jar files:'
	for jar in jarfiles:
		print jar
localpath = localpath + SEPARATOR + string.join(jarfiles, SEPARATOR)

# If JAVA_HOME is defined, look for tools.jar & classes.zip
# and add to classpath
if os.environ.has_key('JAVA_HOME') and os.environ['JAVA_HOME'] != '':
	JAVA_HOME = os.environ['JAVA_HOME']
	TOOLS = os.path.join(JAVA_HOME, os.path.join('lib', 'tools.jar'))
	if os.path.exists(TOOLS):
		localpath = localpath + SEPARATOR + TOOLS
	CLASSES = os.path.join(JAVA_HOME, os.path.join('lib', 'classes.zip'))
	if os.path.exists(CLASSES):
		localpath = localpath + SEPARATOR + CLASSES
else:
	print '\n\nWarning: JAVA_HOME environment variable is not set.\n', \
		'If the build fails because sun.* classes could not be found\n', \
		'you will need to set the JAVA_HOME environment variable\n', \
		'to the installation directory of java\n'

# Jikes
ANT_OPTS = []
if os.environ.has_key('ANT_OPTS'):
	ANT_OPTS = string.split(os.environ['ANT_OPTS'])
if os.environ.has_key('JIKESPATH'):
	ANT_OPTS.append('-Djikes.class.path=' + os.environ['JIKESPATH'])

# Builds the commandline
cmdline = '%s -classpath %s -Dant.home=%s %s org.apache.tools.ant.Main %s' \
	 % (JAVACMD, localpath, ANT_HOME, string.join(ANT_OPTS,' '), \
	 	string.join(sys.argv[1:], ' '))

if debug:
	print '\n%s\n\n' % (cmdline)

# Run the biniou!
os.system(cmdline)

首先想到classpath配的有问题, 的确如此. 如果你在Jython中运行下面这段脚本, 会发现ant.jar的前的分隔符是':', 我是在windows上运行的所以应该是';' 但这段关于分隔符的判定有似乎没问题

# Sets the separator char for CLASSPATH
SEPARATOR = ':'
if os.name == 'dos' or os.name == 'nt':
	SEPARATOR = ';'

如果我们调试一下会发现os.name的输出其实是既不是'dos', 也不是'nt', 而是'java'
再查看一下python的doc, http://docs.python.org/library/os.html, os.name的枚举值里的确有'java'.

这说明Python和Jython的实现肯定还是有差别的, 毕竟Jython是用纯java的实现的. 在java中可以用System.getProperty("os.name")取得系统类型. 不知道Jython为何将os.name设为'java'. 希望哪位python大牛给出jython的初衷.

找了一下os.environ中的键值对, 找到下面的方法可以在Jython中正确运行

# Sets the separator char for CLASSPATH
SEPARATOR = ';'
if not os.environ['OS'] == 'Windows_NT':
	SEPARATOR = ':'