Python装饰器学习-优快云博客

原文链接：http://blog.youkuaiyun.com/dreamcoding/article/details/8611578

Python装饰器学习（九步入门）

这是在Python学习小组上介绍的内容，现学现卖、多练习是好的学习方式。

第一步：最简单的函数，准备附加额外功能

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 566px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例1: 最简单的函数,表示调用了两次'''</span><span>  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">def</span><span> myfunc():  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">"myfunc() called."</span><span>)  </span></span></li><li><span>  </span></li><li class="alt"><span>myfunc()  </span></li><li><span>myfunc()  </span></li></ol><div class="save_code tracking-ad" style="display: none;" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例1: 最简单的函数,表示调用了两次'''

def myfunc():
    print("myfunc() called.")

myfunc()
myfunc()

第二步：使用装饰函数在函数执行前和执行后分别附加额外功能

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 843px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例2: 替换函数(装饰)</span> </span></li><li class="alt"><span><span class="comment">装饰函数的参数是被装饰的函数对象，返回原函数对象</span> </span></li><li><span><span class="comment">装饰的实质语句: myfunc = deco(myfunc)'''</span><span>  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">def</span><span> deco(func):  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">"before myfunc() called."</span><span>)  </span></span></li><li><span>    func()  </span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">"  after myfunc() called."</span><span>)  </span></span></li><li><span>    <span class="keyword">return</span><span> func  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">def</span><span> myfunc():  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc() called."</span><span>)  </span></span></li><li><span>  </span></li><li class="alt"><span>myfunc = deco(myfunc)  </span></li><li><span>  </span></li><li class="alt"><span>myfunc()  </span></li><li><span>myfunc()  </span></li></ol><div class="save_code tracking-ad" style="display: none;" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例2: 替换函数(装饰)
装饰函数的参数是被装饰的函数对象，返回原函数对象
装饰的实质语句: myfunc = deco(myfunc)'''

def deco(func):
    print("before myfunc() called.")
    func()
    print("  after myfunc() called.")
    return func

def myfunc():
    print(" myfunc() called.")

myfunc = deco(myfunc)

myfunc()
myfunc()

第三步：使用语法糖@来装饰函数

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 1267px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例3: 使用语法糖@来装饰函数，相当于“myfunc = deco(myfunc)”</span> </span></li><li class="alt"><span><span class="comment">但发现新函数只在第一次被调用，且原函数多调用了一次'''</span><span>  </span></span></li><li><span>  </span></li><li class="alt"><span><span class="keyword">def</span><span> deco(func):  </span></span></li><li><span>    <span class="keyword">print</span><span>(</span><span class="string">"before myfunc() called."</span><span>)  </span></span></li><li class="alt"><span>    func()  </span></li><li><span>    <span class="keyword">print</span><span>(</span><span class="string">"  after myfunc() called."</span><span>)  </span></span></li><li class="alt"><span>    <span class="keyword">return</span><span> func  </span></span></li><li><span><span class="decorator"></span> </span></li><li class="alt"><span><span class="decorator">@deco</span><span>  </span></span></li><li><span><span class="keyword">def</span><span> myfunc():  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc() called."</span><span>)  </span></span></li><li><span>  </span></li><li class="alt"><span>myfunc()  </span></li><li><span>myfunc()  </span></li></ol><div class="save_code tracking-ad" style="display: none;" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例3: 使用语法糖@来装饰函数，相当于“myfunc = deco(myfunc)”
但发现新函数只在第一次被调用，且原函数多调用了一次'''

def deco(func):
    print("before myfunc() called.")
    func()
    print("  after myfunc() called.")
    return func

@deco
def myfunc():
    print(" myfunc() called.")

myfunc()
myfunc()

第四步：使用内嵌包装函数来确保每次新函数都被调用

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 1653px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例4: 使用内嵌包装函数来确保每次新函数都被调用，</span> </span></li><li class="alt"><span><span class="comment">内嵌包装函数的形参和返回值与原函数相同，装饰函数返回内嵌包装函数对象'''</span><span>  </span></span></li><li><span>  </span></li><li class="alt"><span><span class="keyword">def</span><span> deco(func):  </span></span></li><li><span>    <span class="keyword">def</span><span> _deco():  </span></span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"before myfunc() called."</span><span>)  </span></span></li><li><span>        func()  </span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"  after myfunc() called."</span><span>)  </span></span></li><li><span>        <span class="comment"># 不需要返回func，实际上应返回原函数的返回值</span><span>  </span></span></li><li class="alt"><span>    <span class="keyword">return</span><span> _deco  </span></span></li><li><span><span class="decorator"></span> </span></li><li class="alt"><span><span class="decorator">@deco</span><span>  </span></span></li><li><span><span class="keyword">def</span><span> myfunc():  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc() called."</span><span>)  </span></span></li><li><span>    <span class="keyword">return</span><span> </span><span class="string">'ok'</span><span>  </span></span></li><li class="alt"><span>  </span></li><li><span>myfunc()  </span></li><li class="alt"><span>myfunc()  </span></li></ol><div class="save_code tracking-ad" style="display: none;" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例4: 使用内嵌包装函数来确保每次新函数都被调用，
内嵌包装函数的形参和返回值与原函数相同，装饰函数返回内嵌包装函数对象'''

def deco(func):
    def _deco():
        print("before myfunc() called.")
        func()
        print("  after myfunc() called.")
        # 不需要返回func，实际上应返回原函数的返回值
    return _deco

@deco
def myfunc():
    print(" myfunc() called.")
    return 'ok'

myfunc()
myfunc()

第五步：对带参数的函数进行装饰

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 2096px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例5: 对带参数的函数进行装饰，</span> </span></li><li class="alt"><span><span class="comment">内嵌包装函数的形参和返回值与原函数相同，装饰函数返回内嵌包装函数对象'''</span><span>  </span></span></li><li><span>  </span></li><li class="alt"><span><span class="keyword">def</span><span> deco(func):  </span></span></li><li><span>    <span class="keyword">def</span><span> _deco(a, b):  </span></span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"before myfunc() called."</span><span>)  </span></span></li><li><span>        ret = func(a, b)  </span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"  after myfunc() called. result: %s"</span><span> % ret)  </span></span></li><li><span>        <span class="keyword">return</span><span> ret  </span></span></li><li class="alt"><span>    <span class="keyword">return</span><span> _deco  </span></span></li><li><span><span class="decorator"></span> </span></li><li class="alt"><span><span class="decorator">@deco</span><span>  </span></span></li><li><span><span class="keyword">def</span><span> myfunc(a, b):  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc(%s,%s) called."</span><span> % (a, b))  </span></span></li><li><span>    <span class="keyword">return</span><span> a + b  </span></span></li><li class="alt"><span>  </span></li><li><span>myfunc(<span class="number">1</span><span>, </span><span class="number">2</span><span>)  </span></span></li><li class="alt"><span>myfunc(<span class="number">3</span><span>, </span><span class="number">4</span><span>)  </span></span></li></ol><div class="save_code tracking-ad" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例5: 对带参数的函数进行装饰，
内嵌包装函数的形参和返回值与原函数相同，装饰函数返回内嵌包装函数对象'''

def deco(func):
    def _deco(a, b):
        print("before myfunc() called.")
        ret = func(a, b)
        print("  after myfunc() called. result: %s" % ret)
        return ret
    return _deco

@deco
def myfunc(a, b):
    print(" myfunc(%s,%s) called." % (a, b))
    return a + b

myfunc(1, 2)
myfunc(3, 4)

第六步：对参数数量不确定的函数进行装饰

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 2538px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例6: 对参数数量不确定的函数进行装饰，</span> </span></li><li class="alt"><span><span class="comment">参数用(*args, **kwargs)，自动适应变参和命名参数'''</span><span>  </span></span></li><li><span>  </span></li><li class="alt"><span><span class="keyword">def</span><span> deco(func):  </span></span></li><li><span>    <span class="keyword">def</span><span> _deco(*args, **kwargs):  </span></span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"before %s called."</span><span> % func.__name__)  </span></span></li><li><span>        ret = func(*args, **kwargs)  </span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"  after %s called. result: %s"</span><span> % (func.__name__, ret))  </span></span></li><li><span>        <span class="keyword">return</span><span> ret  </span></span></li><li class="alt"><span>    <span class="keyword">return</span><span> _deco  </span></span></li><li><span><span class="decorator"></span> </span></li><li class="alt"><span><span class="decorator">@deco</span><span>  </span></span></li><li><span><span class="keyword">def</span><span> myfunc(a, b):  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc(%s,%s) called."</span><span> % (a, b))  </span></span></li><li><span>    <span class="keyword">return</span><span> a+b  </span></span></li><li class="alt"><span><span class="decorator"></span> </span></li><li><span><span class="decorator">@deco</span><span>  </span></span></li><li class="alt"><span><span class="keyword">def</span><span> myfunc2(a, b, c):  </span></span></li><li><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc2(%s,%s,%s) called."</span><span> % (a, b, c))  </span></span></li><li class="alt"><span>    <span class="keyword">return</span><span> a+b+c  </span></span></li><li><span>  </span></li><li class="alt"><span>myfunc(<span class="number">1</span><span>, </span><span class="number">2</span><span>)  </span></span></li><li><span>myfunc(<span class="number">3</span><span>, </span><span class="number">4</span><span>)  </span></span></li><li class="alt"><span>myfunc2(<span class="number">1</span><span>, </span><span class="number">2</span><span>, </span><span class="number">3</span><span>)  </span></span></li><li><span>myfunc2(<span class="number">3</span><span>, </span><span class="number">4</span><span>, </span><span class="number">5</span><span>)  </span></span></li></ol><div class="save_code tracking-ad" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例6: 对参数数量不确定的函数进行装饰，
参数用(*args, **kwargs)，自动适应变参和命名参数'''

def deco(func):
    def _deco(*args, **kwargs):
        print("before %s called." % func.__name__)
        ret = func(*args, **kwargs)
        print("  after %s called. result: %s" % (func.__name__, ret))
        return ret
    return _deco

@deco
def myfunc(a, b):
    print(" myfunc(%s,%s) called." % (a, b))
    return a+b

@deco
def myfunc2(a, b, c):
    print(" myfunc2(%s,%s,%s) called." % (a, b, c))
    return a+b+c

myfunc(1, 2)
myfunc(3, 4)
myfunc2(1, 2, 3)
myfunc2(3, 4, 5)

第七步：让装饰器带参数

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 3111px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例7: 在示例4的基础上，让装饰器带参数，</span> </span></li><li class="alt"><span><span class="comment">和上一示例相比在外层多了一层包装。</span> </span></li><li><span><span class="comment">装饰函数名实际上应更有意义些'''</span><span>  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">def</span><span> deco(arg):  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> _deco(func):  </span></span></li><li><span>        <span class="keyword">def</span><span> __deco():  </span></span></li><li class="alt"><span>            <span class="keyword">print</span><span>(</span><span class="string">"before %s called [%s]."</span><span> % (func.__name__, arg))  </span></span></li><li><span>            func()  </span></li><li class="alt"><span>            <span class="keyword">print</span><span>(</span><span class="string">"  after %s called [%s]."</span><span> % (func.__name__, arg))  </span></span></li><li><span>        <span class="keyword">return</span><span> __deco  </span></span></li><li class="alt"><span>    <span class="keyword">return</span><span> _deco  </span></span></li><li><span><span class="decorator"></span> </span></li><li class="alt"><span><span class="decorator">@deco</span><span>(</span><span class="string">"mymodule"</span><span>)  </span></span></li><li><span><span class="keyword">def</span><span> myfunc():  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc() called."</span><span>)  </span></span></li><li><span><span class="decorator"></span> </span></li><li class="alt"><span><span class="decorator">@deco</span><span>(</span><span class="string">"module2"</span><span>)  </span></span></li><li><span><span class="keyword">def</span><span> myfunc2():  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc2() called."</span><span>)  </span></span></li><li><span>  </span></li><li class="alt"><span>myfunc()  </span></li><li><span>myfunc2()  </span></li></ol><div class="save_code tracking-ad" style="display: none;" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例7: 在示例4的基础上，让装饰器带参数，
和上一示例相比在外层多了一层包装。
装饰函数名实际上应更有意义些'''

def deco(arg):
    def _deco(func):
        def __deco():
            print("before %s called [%s]." % (func.__name__, arg))
            func()
            print("  after %s called [%s]." % (func.__name__, arg))
        return __deco
    return _deco

@deco("mymodule")
def myfunc():
    print(" myfunc() called.")

@deco("module2")
def myfunc2():
    print(" myfunc2() called.")

myfunc()
myfunc2()

第八步：让装饰器带类参数

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 3647px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例8: 装饰器带类参数'''</span><span>  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">class</span><span> locker:  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> __init__(</span><span class="special">self</span><span>):  </span></span></li><li><span>        <span class="keyword">print</span><span>(</span><span class="string">"locker.__init__() should be not called."</span><span>)  </span></span></li><li class="alt"><span><span class="decorator">        </span> </span></li><li><span><span class="decorator">    @staticmethod</span><span>  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> acquire():  </span></span></li><li><span>        <span class="keyword">print</span><span>(</span><span class="string">"locker.acquire() called.（这是静态方法）"</span><span>)  </span></span></li><li class="alt"><span><span class="decorator">        </span> </span></li><li><span><span class="decorator">    @staticmethod</span><span>  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> release():  </span></span></li><li><span>        <span class="keyword">print</span><span>(</span><span class="string">"  locker.release() called.（不需要对象实例）"</span><span>)  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">def</span><span> deco(</span><span class="special">cls</span><span>):  </span></span></li><li class="alt"><span>    <span class="string">''</span><span class="comment">'''cls 必须实现acquire和release静态方法'''</span><span>  </span></span></li><li><span>    <span class="keyword">def</span><span> _deco(func):  </span></span></li><li class="alt"><span>        <span class="keyword">def</span><span> __deco():  </span></span></li><li><span>            <span class="keyword">print</span><span>(</span><span class="string">"before %s called [%s]."</span><span> % (func.__name__, </span><span class="special">cls</span><span>))  </span></span></li><li class="alt"><span>            <span class="special">cls</span><span>.acquire()  </span></span></li><li><span>            <span class="keyword">try</span><span>:  </span></span></li><li class="alt"><span>                <span class="keyword">return</span><span> func()  </span></span></li><li><span>            <span class="keyword">finally</span><span>:  </span></span></li><li class="alt"><span>                <span class="special">cls</span><span>.release()  </span></span></li><li><span>        <span class="keyword">return</span><span> __deco  </span></span></li><li class="alt"><span>    <span class="keyword">return</span><span> _deco  </span></span></li><li><span><span class="decorator"></span> </span></li><li class="alt"><span><span class="decorator">@deco</span><span>(locker)  </span></span></li><li><span><span class="keyword">def</span><span> myfunc():  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(</span><span class="string">" myfunc() called."</span><span>)  </span></span></li><li><span>  </span></li><li class="alt"><span>myfunc()  </span></li><li><span>myfunc()  </span></li></ol><div class="save_code tracking-ad" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例8: 装饰器带类参数'''

class locker:
    def __init__(self):
        print("locker.__init__() should be not called.")
        
    @staticmethod
    def acquire():
        print("locker.acquire() called.（这是静态方法）")
        
    @staticmethod
    def release():
        print("  locker.release() called.（不需要对象实例）")

def deco(cls):
    '''cls 必须实现acquire和release静态方法'''
    def _deco(func):
        def __deco():
            print("before %s called [%s]." % (func.__name__, cls))
            cls.acquire()
            try:
                return func()
            finally:
                cls.release()
        return __deco
    return _deco

@deco(locker)
def myfunc():
    print(" myfunc() called.")

myfunc()
myfunc()

第九步：装饰器带类参数，并分拆公共类到其他py文件中，同时演示了对一个函数应用多个装饰器

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 4396px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''mylocker.py: 公共类 for 示例9.py'''</span><span>  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">class</span><span> mylocker:  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> __init__(</span><span class="special">self</span><span>):  </span></span></li><li><span>        <span class="keyword">print</span><span>(</span><span class="string">"mylocker.__init__() called."</span><span>)  </span></span></li><li class="alt"><span><span class="decorator">        </span> </span></li><li><span><span class="decorator">    @staticmethod</span><span>  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> acquire():  </span></span></li><li><span>        <span class="keyword">print</span><span>(</span><span class="string">"mylocker.acquire() called."</span><span>)  </span></span></li><li class="alt"><span><span class="decorator">        </span> </span></li><li><span><span class="decorator">    @staticmethod</span><span>  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> unlock():  </span></span></li><li><span>        <span class="keyword">print</span><span>(</span><span class="string">"  mylocker.unlock() called."</span><span>)  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">class</span><span> lockerex(mylocker):  </span></span></li><li class="alt"><span><span class="decorator">    @staticmethod</span><span>  </span></span></li><li><span>    <span class="keyword">def</span><span> acquire():  </span></span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"lockerex.acquire() called."</span><span>)  </span></span></li><li><span><span class="decorator">        </span> </span></li><li class="alt"><span><span class="decorator">    @staticmethod</span><span>  </span></span></li><li><span>    <span class="keyword">def</span><span> unlock():  </span></span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">"  lockerex.unlock() called."</span><span>)  </span></span></li><li><span>  </span></li><li class="alt"><span><span class="keyword">def</span><span> lockhelper(</span><span class="special">cls</span><span>):  </span></span></li><li><span>    <span class="string">''</span><span class="comment">'''cls 必须实现acquire和release静态方法'''</span><span>  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> _deco(func):  </span></span></li><li><span>        <span class="keyword">def</span><span> __deco(*args, **kwargs):  </span></span></li><li class="alt"><span>            <span class="keyword">print</span><span>(</span><span class="string">"before %s called."</span><span> % func.__name__)  </span></span></li><li><span>            <span class="special">cls</span><span>.acquire()  </span></span></li><li class="alt"><span>            <span class="keyword">try</span><span>:  </span></span></li><li><span>                <span class="keyword">return</span><span> func(*args, **kwargs)  </span></span></li><li class="alt"><span>            <span class="keyword">finally</span><span>:  </span></span></li><li><span>                <span class="special">cls</span><span>.unlock()  </span></span></li><li class="alt"><span>        <span class="keyword">return</span><span> __deco  </span></span></li><li><span>    <span class="keyword">return</span><span> _deco  </span></span></li></ol><div class="save_code tracking-ad" style="display: none;" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''mylocker.py: 公共类 for 示例9.py'''

class mylocker:
    def __init__(self):
        print("mylocker.__init__() called.")
        
    @staticmethod
    def acquire():
        print("mylocker.acquire() called.")
        
    @staticmethod
    def unlock():
        print("  mylocker.unlock() called.")

class lockerex(mylocker):
    @staticmethod
    def acquire():
        print("lockerex.acquire() called.")
        
    @staticmethod
    def unlock():
        print("  lockerex.unlock() called.")

def lockhelper(cls):
    '''cls 必须实现acquire和release静态方法'''
    def _deco(func):
        def __deco(*args, **kwargs):
            print("before %s called." % func.__name__)
            cls.acquire()
            try:
                return func(*args, **kwargs)
            finally:
                cls.unlock()
        return __deco
    return _deco

<div class="dp-highlighter bg_python"><div class="bar"><div class="tools"><strong>[python]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">view plain</a><span data-mod="popu_168"> <a target=_blank title="copy" class="CopyToClipboard" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">copy</a></span><div style="left: 630px; top: 5111px; width: 21px; height: 11px; position: absolute; z-index: 99;"></div><span data-mod="popu_169"> <a target=_blank title="print" class="PrintSource" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">print</a></span><a target=_blank title="?" class="About" href="http://blog.youkuaiyun.com/dreamcoding/article/details/8611578#">?</a></div></div><ol class="dp-py"><li class="alt"><span><span class="comment"># -*- coding:gbk -*-</span><span>  </span></span></li><li><span><span class="string">''</span><span class="comment">'''示例9: 装饰器带类参数，并分拆公共类到其他py文件中</span> </span></li><li class="alt"><span><span class="comment">同时演示了对一个函数应用多个装饰器'''</span><span>  </span></span></li><li><span>  </span></li><li class="alt"><span><span class="keyword">from</span><span> mylocker </span><span class="keyword">import</span><span> *  </span></span></li><li><span>  </span></li><li class="alt"><span><span class="keyword">class</span><span> example:  </span></span></li><li><span><span class="decorator">    @lockhelper</span><span>(mylocker)  </span></span></li><li class="alt"><span>    <span class="keyword">def</span><span> myfunc(</span><span class="special">self</span><span>):  </span></span></li><li><span>        <span class="keyword">print</span><span>(</span><span class="string">" myfunc() called."</span><span>)  </span></span></li><li class="alt"><span><span class="decorator"></span> </span></li><li><span><span class="decorator">    @lockhelper</span><span>(mylocker)  </span></span></li><li class="alt"><span><span class="decorator">    @lockhelper</span><span>(lockerex)  </span></span></li><li><span>    <span class="keyword">def</span><span> myfunc2(</span><span class="special">self</span><span>, a, b):  </span></span></li><li class="alt"><span>        <span class="keyword">print</span><span>(</span><span class="string">" myfunc2() called."</span><span>)  </span></span></li><li><span>        <span class="keyword">return</span><span> a + b  </span></span></li><li class="alt"><span>  </span></li><li><span><span class="keyword">if</span><span> __name__==</span><span class="string">"__main__"</span><span>:  </span></span></li><li class="alt"><span>    a = example()  </span></li><li><span>    a.myfunc()  </span></li><li class="alt"><span>    <span class="keyword">print</span><span>(a.myfunc())  </span></span></li><li><span>    <span class="keyword">print</span><span>(a.myfunc2(</span><span class="number">1</span><span>, </span><span class="number">2</span><span>))  </span></span></li><li class="alt"><span>    <span class="keyword">print</span><span>(a.myfunc2(</span><span class="number">3</span><span>, </span><span class="number">4</span><span>))  </span></span></li></ol><div class="save_code tracking-ad" style="display: none;" data-mod="popu_249"><a target=_blank target="_blank"><img src="http://static.blog.youkuaiyun.com/images/save_snippets.png" alt="" /></a></div></div><pre class="python" style="display: none;" name="code"># -*- coding:gbk -*-
'''示例9: 装饰器带类参数，并分拆公共类到其他py文件中
同时演示了对一个函数应用多个装饰器'''

from mylocker import *

class example:
    @lockhelper(mylocker)
    def myfunc(self):
        print(" myfunc() called.")

    @lockhelper(mylocker)
    @lockhelper(lockerex)
    def myfunc2(self, a, b):
        print(" myfunc2() called.")
        return a + b

if __name__=="__main__":
    a = example()
    a.myfunc()
    print(a.myfunc())
    print(a.myfunc2(1, 2))
    print(a.myfunc2(3, 4))

下面是参考资料，当初有不少地方没看明白，真正练习后才明白些：

1. Python装饰器学习 http://blog.csdn .NET/thy38/article/details/4471421

2. Python装饰器与面向切面编程 http://www.cnblogs.com/huxi/archive/2011/03/01/1967600.html

3. Python装饰器的理解 http://apps.hi.baidu.com/share/detail/17572338