Java如何访问类的私有静态成员

Question

Hi may I know how to access private static member outside Java classes?

I want to check if a value is set correctly.

Answer 1

(All necessary alerts about using reflection.)

Using reflection

import java.lang.reflect.Field;

public class Test {
    public static void main(String[] args) throws Exception {
//      Class<A> clazz = A.class;            // if you know the class statically i.e. at compile time
        Class<?> clazz = Class.forName("A"); // if you know class name dynamically i.e. at runtime
        Field field = clazz.getDeclaredField("x");
        field.setAccessible(true);
        System.out.println(field.getInt(null)); // 10
    }
}

class A {
    private static int x = 10;
}

null is because the field is static, so there is no need in an instance of A .

How to read the value of a private field from a different class in Java?

Answer 2

I've never used it, but I've heard that PowerMock is capable of testing private methods as well. https://github.com/powermock/powermock