对于类A、B,A是B的基类,A有一个私有成员name
A.java
public class A {
private String name = "A"; public void print() {
System.out.println(name);
}
}
B.java
public class B extends A {
}
对于A对象a,要想改变a的name,可以这样操作:
try {
Field nameFieldInA = a.getClass().getDeclaredField("name");
nameFieldInA.setAccessible(true);
nameFieldInA.set(a, "一");
a.print();
} catch (NoSuchFieldException | IllegalAccessException ex) {
ex.printStackTrace();
}
要访问a的name,可执行nameFieldInA.get(a)
对于B对象b,要改变b的name,可以这样:
import java.lang.reflect.Field; public class Main {
public static void main(String[] args) {
try {
B b = new B();
b.print();
Field field = b.getClass().getSuperclass().getDeclaredField("name");
field.setAccessible(true);
field.set(b, "B");
b.print();
} catch (NoSuchFieldException | IllegalAccessException ex) {
ex.printStackTrace();
}
}
}