框原始类型的方法

Question

Here is a table of primitive types and their equivalent wrapper class.

Primitive type  Wrapper class
==============  =============
 boolean        Boolean
 byte           Byte
 char           Character
 float          Float
 int            Integer
 long           Long
 short          Short
 double         Double

I would like to create a method that would convert any given primitive variable into an appropriate class. I have tried something like below, but that obviously does not work. Any help would be appreciated:

public static <T> T forceBox(T t) {
  switch (T) {
    case boolean.class : return new Boolean(t);
    case int.class     : return new Integer(t);
    // etc
  }
}

the caller code looks like:

int x = 3;
System.out.println("x wrapper type: " + forceBox(x).getClass());

Answer 1

Though this is completely unnecessary in most cases, just use

public static <T> T forceBox(T t) { // compiler will add the conversion at the call site
    return t; 
}

Though you can also just use

Object o = <some primitive>;

Answer 2

作为装箱过程的一部分，转换已在需要时完成。