How do I know if a class has a method in java and how do I invoke it

Question

I need to know if a java class has the method

public double getValue() 

if there is a method. I need call the method.

Sorry, I forgot to say that this need to do at runtime

Answer 1

You could use Class.getMethod() to get the Method object, and then Method.call() to invoke the method.

getMethod() will throw NoSuchMethodException if the class doesn't have a method with the requested name and signature.

Answer 2

You need to get the class, and then the methods from the class. Assume angst is your object.

Object angst = new Object();
Method[] methods= angst.getClass().getMethods();
for(i=0; i<methods.length; i++) {
    if(methods[i].getName().equals("getValue") {
        //some boolean stuff
    }
}

Answer 3

您必须使用Java Reflection