私有方法的api不一定就是完全安全的, 单例模式的私有构造器也不一定能保证自己一定是单例
在产品平台上做开发, 有时候你总会需要jad, 继承, cglib 或者 反射
package name.lizhe;
public class Employee {
private void setSalary(int i){
System.out.println("changed salary to:"+i);
}
}package name.lizhe;
import java.lang.reflect.InvocationTargetException;
public class Executor {
public static void main(String[] args) throws NoSuchMethodException, SecurityException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException {
Employee emp = new Employee();
Class[] cArg = new Class[1];
cArg[0] = int.class;
java.lang.reflect.Method m = Employee.class.getDeclaredMethod("setSalary", cArg);
m.setAccessible(true);
m.invoke(emp, 10000);
}
}
如果是私有构造方法的话略微 有些不同
package name.lizhe;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
public class Executor {
public static void main(String[] args) throws NoSuchMethodException, SecurityException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException, InstantiationException {
Employee emp = Employee.getInstance();
Class[] cArg = new Class[1];
cArg[0] = int.class;
Constructor<Employee> m = Employee.class.getDeclaredConstructor();
m.setAccessible(true);
Employee emp2 = (Employee) m.newInstance(null);
System.out.println(emp==emp2);
}
}