有没有可以用Python反序列化Java序列化的数据的库？
有没有什么库可以用Python来解码那些用Java编码的数据？
7 个回答
5
Java的二进制序列化其实是专门为Java设计的。如果你想在Python中使用，就得有所有相关的Java类可以查看，然后还得相应地创建Python对象，这样做会非常麻烦而且不稳定。
与其这样，不如使用一些跨平台的序列化格式，比如Thrift、Protocol Buffers、JSON或者XML。如果你不能改变Java代码中使用的序列化格式，我建议你写一些新的Java代码，先把二进制格式的数据反序列化出来，然后再转成一个跨平台的格式。
9
这里有一个非常简单的实现方法，不需要任何额外的库。这里的一个难点是，有些类有自己的序列化方式，这就需要原始代码来进行反序列化。另外，我的文件是经过gzip压缩的，不过我没有提供相关的代码。我参考了这两个网页：
http://www.javaworld.com/community/node/2915 http://docs.oracle.com/javase/7/docs/platform/serialization/spec/protocol.html
#!/usr/bin/python
def parse(f):
h = lambda s: ' '.join('%.2X' % ord(x) for x in s) # format as hex
p = lambda s: sum(ord(x)*256**i for i, x in enumerate(reversed(s))) # parse integer
magic = f.read(2)
assert magic == '\xAC\xED', h(magic) # STREAM_MAGIC
assert p(f.read(2)) == 5 # STREAM_VERSION
handles = []
def parse_obj():
b = f.read(1)
if not b:
raise StopIteration # not necessarily the best thing to throw here.
if b == '\x70': # p TC_NULL
return None
elif b == '\x71': # q TC_REFERENCE
handle = p(f.read(4)) - 0x7E0000 # baseWireHandle
o = handles[handle]
return o[1]
elif b == '\x74': # t TC_STRING
string = f.read(p(f.read(2))).decode('utf-8')
handles.append(('TC_STRING', string))
return string
elif b == '\x75': # u TC_ARRAY
data = []
cls = parse_obj()
size = p(f.read(4))
handles.append(('TC_ARRAY', data))
assert cls['_name'] in ('[B', '[I'), (cls['_name'], size, f.read(50))
for x in range(size):
data.append(f.read({'[B': 1, '[I': 4}[cls['_name']]))
return data
elif b == '\x7E': # ~ TC_ENUM
enum = {}
enum['_cls'] = parse_obj()
handles.append(('TC_ENUM', enum))
enum['_name'] = parse_obj()
return enum
elif b == '\x72': # r TC_CLASSDESC
cls = {'fields': []}
full_name = f.read(p(f.read(2)))
cls['_name'] = full_name.split('.')[-1] # i don't care about full path
f.read(8) # uid
cls['flags'] = f.read(1)
handles.append(('TC_CLASSDESC', cls))
assert cls['flags'] in ('\2', '\3', '\x0C', '\x12'), h(cls['flags'])
b = f.read(2)
for i in range(p(b)):
typ = f.read(1)
name = f.read(p(f.read(2)))
fcls = parse_obj() if typ in 'L[' else ''
cls['fields'].append((name, typ, fcls.split('/')[-1])) # don't care about full path
b = f.read(1)
assert b == '\x78', h(b)
cls['parent'] = parse_obj()
return cls
# TC_OBJECT
assert b == '\x73', (h(b), h(f.read(4)), f.read(50))
obj = {}
obj['_cls'] = parse_obj()
obj['_name'] = obj['_cls']['_name']
handle = len(handles)
parents = [obj['_cls']]
while parents[0]['parent']:
parents.insert(0, parents[0]['parent'])
handles.append(('TC_OBJECT', obj))
for cls in parents:
for name, typ, fcls in cls['fields'] if cls['flags'] in ('\2', '\3') else []:
if typ == 'I': # Integer
obj[name] = p(f.read(4))
elif typ == 'S': # Short
obj[name] = p(f.read(2))
elif typ == 'J': # Long
obj[name] = p(f.read(8))
elif typ == 'Z': # Bool
b = f.read(1)
assert p(b) in (0, 1)
obj[name] = bool(p(b))
elif typ == 'F': # Float
obj[name] = h(f.read(4))
elif typ in 'BC': # Byte, Char
obj[name] = f.read(1)
elif typ in 'L[': # Object, Array
obj[name] = parse_obj()
else: # Unknown
assert False, (name, typ, fcls)
if cls['flags'] in ('\3', '\x0C'): # SC_WRITE_METHOD, SC_BLOCKDATA
b = f.read(1)
if b == '\x77': # see the readObject / writeObject methods
block = f.read(p(f.read(1)))
if cls['_name'].endswith('HashMap') or cls['_name'].endswith('Hashtable'):
# http://javasourcecode.org/html/open-source/jdk/jdk-6u23/java/util/HashMap.java.html
# http://javasourcecode.org/html/open-source/jdk/jdk-6u23/java/util/Hashtable.java.html
assert len(block) == 8, h(block)
size = p(block[4:])
obj['data'] = [] # python doesn't allow dicts as keys
for i in range(size):
k = parse_obj()
v = parse_obj()
obj['data'].append((k, v))
try:
obj['data'] = dict(obj['data'])
except TypeError:
pass # non hashable keys
elif cls['_name'].endswith('HashSet'):
# http://javasourcecode.org/html/open-source/jdk/jdk-6u23/java/util/HashSet.java.html
assert len(block) == 12, h(block)
size = p(block[-4:])
obj['data'] = []
for i in range(size):
obj['data'].append(parse_obj())
elif cls['_name'].endswith('ArrayList'):
# http://javasourcecode.org/html/open-source/jdk/jdk-6u23/java/util/ArrayList.java.html
assert len(block) == 4, h(block)
obj['data'] = []
for i in range(obj['size']):
obj['data'].append(parse_obj())
else:
assert False, cls['_name']
b = f.read(1)
assert b == '\x78', h(b) + ' ' + repr(f.read(50)) # TC_ENDBLOCKDATA
handles[handle] = ('py', obj)
return obj
objs = []
while 1:
try:
objs.append(parse_obj())
except StopIteration:
return objs
if __name__ == '__main__':
import sys, json
json.dump(parse(sys.stdin), sys.stdout, indent=2)