In Java, is it possible to print the type of a variable?
public static void printVariableType(Object theVariable){
//print the type of the variable that is passed as a parameter
//for example, if the variable is a string, print "String" to the console.
}
One approach to this problem would be to use an if-statement for each variable type, but that would seem redundant, so I'm wondering if there's a better way to do this:
if(theVariable instanceof String){
System.out.println("String");
}
if(theVariable instanceof Integer){
System.out.println("Integer");
}
// this seems redundant and verbose. Is there a more efficient solution (e. g., using reflection?).
7 Answers
Based on your example it looks like you want to get type of value held by variable, not declared type of variable. So I am assuming that in case of Animal animal = new Cat(); you want to get Cat not Animal.
To get only name without package part use
String name = theVariable.getClass().getSimpleName(); //to get Cat
otherwise
String name = theVariable.getClass().getName(); //to get full.package.name.of.Cat
System.out.println(theVariable.getClass());
Read the javadoc.
You can use the ".getClass()" method.
System.out.println(variable.getClass());
variable.getClass().getName();
Returns the runtime class of this Object. The returned Class object is the object that is locked by static synchronized methods of the represented class.
public static void printVariableType(Object theVariable){
System.out.println(theVariable.getClass())
}
You can read in the class, and then get it's name.
Class objClass = obj.getClass();
System.out.println("Type: " + objClass.getName());
public static void printVariableType(Object theVariable){
System.out.println(theVariable);
System.out.println(theVariable.getClass());
System.out.println(theVariable.getClass().getName());}
ex- printVariableType("Stackoverflow");
o/p: class java.lang.String // var.getClass()
java.lang.String // var.getClass().getName()
