Update content src/site/notes/ProgrammingLanguages/python/context man…

…ager.md

src/site/notes/ProgrammingLanguages/python/context manager.md

@@ -8,4 +8,26 @@ https://stackoverflow.com/questions/1984325/explaining-pythons-enter-and-exit
 > [!NOTE] With statement
 > **with** statement only works with objects that support the context management protocol (i.e. they have `__enter__` and `__exit__` methods). A class which implement both methods is known as context manager class.
 
-with语句可以支持context manager的类，也就是实现了`__enter__`和`__exit__`的类，通过在with block的开始的时候会调用`__enter__`方法来申请资源，在with block结束的时候调用`__exit__`来进行释放资源
+with语句可以支持context manager的类，也就是实现了`__enter__`和`__exit__`的类，通过在with block的开始的时候会调用`__enter__`方法来申请资源，在with block结束的时候调用`__exit__`来进行释放资源
+
+```py
+ class Log:
+    def __init__(self,filename):
+        self.filename=filename
+        self.fp=None    
+    def logging(self,text):
+        self.fp.write(text+'\n')
+    def __enter__(self):
+        print("__enter__")
+        self.fp=open(self.filename,"a+")
+        return self    
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        print("__exit__")
+        self.fp.close()
+
+with Log(r"C:\Users\SharpEl\Desktop\myfile.txt") as logfile:
+    print("Main")
+    logfile.logging("Test1")
+    logfile.logging("Test2")
+
+```