如何在没有方法重载的情况下创建一个接受java中的String []和Integer []的方法？

Question

Let's say you have an integer array and a string array. How can you write a SINGLE method printArray that can print all the elements of both arrays. The method should be able to accept both integer arrays or string arrays. NOTE.. I cannot use method overloading. Any idea to how to go about this?

Answer 1

You should write a generic method

public <T> void printArray(T[] array) {
    //do your printing stuff here; something like this will work
    for ( T elem : array ) {
        System.out.println(elem.toString());
    }
}

When you call the method you just do printArray(arrayOfIntegers) where arrayOfIntegers is

Integer[] arrayOfIntegers;

Answer 2

The only way I see is

public void print(Object o) {
    if (o instanceof String[]) {
        System.out.println(Arrays.toString((String[]) o));
    }
    else if (o instanceof int[]) {
        System.out.println(Arrays.toString((int[]) o));
    }
}

But it's absolutely ugly. You should have two different methods.

If what you have is an Integer[] (instead of an int[] ), then it's simpler, and OK:

public void print(Object[] o) {
    System.out.println(Arrays.toString(o));
}

Answer 3

You can use generics:

public <T> void printArray(T[] array)
{
    for(T elem : array) System.out.println(elem);
}

You would call it like this:

printArray(new Integer[] { 1, 2, 3 });
printArray(new String[] { "Hello", "World" });

Answer 4

You can also have a java-8 based solution like this- printAnyArray() is the required method.

public class ArrayPrinter{
  public static void main(String args[]){
    String strArray[]={"a","b"};
    Integer intArray[]={1,2};
    printAnyArray(strArray);
    printAnyArray(intArray);
}

 public static void printAnyArray(Object[] objectArray){
  Arrays.asList(objectArray).forEach(System.out::println);
 }
}

Answer 5

You can do like this!

class Printer
{
   public <inputType> void printArray(inputType[] array) 
   {
        for (inputType elem: array) 
        {
            System.out.println(elem);
    }
 }
}

Answer 6

You can use ArrayList with Object

import java.util.ArrayList;
    class Printer {
        public void printArray(Object[] a) {
            ArrayList<Object> al = new ArrayList<>();
            for (int i = 0; i < a.length; i++) {
                al.add(a[i]);
            }
            for (int i = 0; i < al.size(); i++) {
                System.out.println(al.get(i));  
            }
        }
    }