是否可以使用Integer动态调用方法和数组？

Question

For example:

3 methods exist

"map1method,

map2method,

map3mehtod"

and I want to call the right one depending on what the integer 'activemap' has currently stored in it.

I could do an If statement

"If (activemap == 1)

map1method;

elseif (activemap ==2)

..."

But is there a possible way of using the integer more efficiently?

Like a "map(activemap)method"

Also could I also call a specific array in a batch of them in the same fashion.

This is all in java by the way.

Answer 1

It is possible via reflection but I would urge you to stay away from that approach. Why not have all three methods built into one? One option would be to use a switch statement to handle the various cases:

void mapMethod(int activemap) {
    switch (activemap) {
    case 1:
        // map1method
        break;
    case 2:
        // map2method
        break;
    case 3:
        // map3method
        break;
     default:
        break;
    }
}

Now, you can call

mapMethod(activemap)

---

If you want to take the reflection approach instead (which as I said I don't think you should), you can do something along the lines of

String methodName = "map" + activemap + "method";
MyClass.class.getDeclaredMethod(methodName).invoke(null);

Answer 2

A switch statement would be slightly easier to read:

switch(activemap) {
   case 1:  map1method(); break;
   case 2:  map2method(); break;
}

You could use reflection to build the method name up at runtime, but that wouldn't be simpler. Reflection is a lot of code.

Answer 3

The most effective way to do this is to either create an enum to represent the different calls and use the int as a lookup for the enum value, or if that's not possible, to use a switch statement. You can use reflection to accomplish what you're talking about (look up a method at runtime based on its name), but it's less efficient and more cumbersome than either of those options.

Answer 4

You can do it using Reflection , It will be something like this:

  java.lang.reflect.Method method;

  method = myObject.getClass().getMethod("map+"activemap"+method", param1.class, param2.class, ..);

  method.invoke(object, arg1, arg2,...);