Java 27-6 reflection of methods in running a class through a configuration file

In the past, if we wanted to invoke a method in a class, it would only look like this:

Cases:

　　There are two classes of cat and dog, with eat and run two member methods:

1  Public classDog {2 3      Public voideat () {4System.out.println ("Dog eats meat");5     }6     7      Public voidrun () {8System.out.println ("Dog planing"));9     }Ten}

 Public class Cat {    publicvoid  eat () {        System.out.println ("Cat eats Fish");    }      Public void run () {        System.out.println ("cat Tree Climbing");}    }

Before, if you want to invoke a method inside a class, you can only do this:

To do so, there is a drawback, if the class more, the method is more, later changes are very troublesome.

1         // the previous practice 2         New Cat (); 3         c.eat (); 4         C.run (); 5         6         New Dog (); 7         d.eat (); 8         D.run ();

So, for the convenience of future changes.

Create a corresponding configuration file and use reflection to access these methods:

Configuration file: (The Properties class represents a persisted set of properties.) Inside the content is the key value of "AAAA=BBB")

Cases:

1 classname=zl_reclfect_05.cat2 methodname=eat

　　

　　Create a reflective class to invoke the methods in the class through the configuration file:

After that you want to invoke which class of which method, only need to go to configure the file to change the corresponding key value is OK.

1 //reflection of the procedure2         3         //Properties Class:4         //C, public string GetProperty (string key): Gets the value based on the key5         6         //Load key value pair data7     8         //first create a property set class9Properties p =NewProperties ();Ten         //encapsulating the configuration file OneFileReader file =NewFileReader ("Class.txt"); A         //gets the collection of keys -         //void Load (InputStream instream) reads the list of attributes (key and element pairs) from the input stream.  - p.load (file); the file.close (); -          -         //get the value of the key (do the configuration file, definitely know the key) -String classname = P.getproperty ("classname"); +String methodname = P.getproperty ("methodname"); -          +         //to invoke a member method with reflection A          at         //get byte file object -Class C =Class.forName (classname); -          -         //create an object without a parameter construct -Constructor con =c.getconstructor (); -Object obj =con.newinstance (); in          -         //Calling Methods toMethod m =C.getmethod (methodname); + M.invoke (obj); -          the         //after that you want to invoke which class of which method, only need to go to configure the file to change the corresponding key value is OK. 

Java 27-6 reflection of methods in running a class through a configuration file