How to obtain a field value using reflection?

Question

void showReflection() throws ClassNotFoundException, InstantiationException, IllegalAccessException {
    int i;
    for (Angajat a : angajati) {
        Class c = a.getClass();
        Field[] fd = c.getDeclaredFields();
        for (i = 0; i < fd.length; i++) {
            String name = fd[i].getName();
            Object o1 = fd[i].getType().newInstance();
            Object o = fd[i].get(o1);
            System.out.print(name + " " + o + "\n");
        }
    }
}

I want to obtain the values of each field of my Angajat class using reflection — Cristian
– Cristian, Commented Mar 31, 2015 at 9:47
@Cristian, I suspect you want to find out the values of the fields on the objects in the angajati list? — aioobe
– aioobe, Commented Mar 31, 2015 at 9:48
"instead throws me an exception" well Java have many exceptions and they are caused by different problems so you should consider editting your question to include more info about them (like stacktrace). — Pshemo
– Pshemo, Commented Mar 31, 2015 at 9:54

aioobe · Accepted Answer · 2015-03-31 09:47:11Z

2

This part is wrong:

Object o1 = fd[i].getType().newInstance();
Object o = fd[i].get(o1);

(because you end up looking at the fields of newly created objects.)

You probably want to do just

Object o = fd[i].get(a);

answered Mar 31, 2015 at 9:47

aioobe

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4 Comments

Pshemo Over a year ago

Consider adding fd[i].setAccessible(true) in case OP would want to read private fields.

Pshemo Over a year ago

Also it may be worth mentioning that since OP seems to know what enhanced-for-loop is (based on for (Angajat a : angajati) fragment) Class c = a.getClass(); Field[] fd = c.getDeclaredFields(); for (i = 0; i < fd.length; i++) { can be replaced with simple for (Field f: a.getClass().getDeclaredFields())

aioobe Over a year ago

Feels kind of off topic for what's being asked. I like to keep my answers to the point.

Pshemo Over a year ago

OK, fair enough, but I will leave my comments just in case.

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