Question

Since I am new to Java, I need some help about some basic things on Java.
I have two questions. They may be very simple(they are at least in C++), but I couldn’t figure out how to do it in Java.

(i) How to split line with comma separated values into separate strings?

Suppose I have an input(text) file like:

 zoo,name,cszoo,address,miami  

    ...,...,...,....

I want to read the input line by line from file and get the strings between commas for each line

(ii) Calling sub class constructor

If I have a superclass called Animal and a subclasses called Dog and Cat. While I read them from input, I put them into a Vector as an Animal. But I need to call their constructor as if they are Dog or Cat. How do I do it in Java

Answer 1

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
// or, to read from a file, do:
// BufferedReader br = new BufferedReader(new FileReader("file.txt"));
String line;
while ((line = br.readLine()) != null) {
    String[] a = line.split(",");

    // do whatever you want here
    // assuming the first element in your array is the class name, you can do this:
    Animal animal = Class.forName(a[0]).newInstance();

    // the problem is that that calls the zero arg constructor. But I'll 
    // leave it up to you to figure out how to find the two arg matching
    // constructor and call that instead (hint: Class.getConstructor(Class[] argTypes))
}