擅长:python、mysql、java
<p>在<code>with</code>语句中包装程序的主体,并定义一个相应的上下文对象,该对象仅在未引发异常时执行操作。比如:</p>
<pre><code>class AtExit(object):
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
if exc_value is None:
print "Success!"
else:
print "Failure!"
if __name__ == "__main__":
with AtExit():
print "Running"
# raise Exception("Error")
</code></pre>