java繼承解析

roland_reed 發(fā)布于2019-08-16 13:49 / 2979人閱讀

摘要：子類從其父類繼承所有成員字段，方法和嵌套類。來自官方文檔調(diào)用父類構(gòu)造方法調(diào)用父類靜態(tài)方法調(diào)用父類方法調(diào)用父類私有方法調(diào)用子類公有方法獲取子類得到父類得到父類非繼承的所以方法設(shè)置私有方法可以被訪問子類調(diào)用方法的調(diào)用結(jié)果運行結(jié)果

A subclass inherits all the members (fields, methods, and nested classes) from its superclass. Constructors are not members, so they are not inherited by subclasses, but the constructor of the superclass can be invoked from the subclass. [子類從其父類繼承所有成員（字段，方法和嵌套類）。構(gòu)造函數(shù)不是成員，所以它們不被子類繼承，但是可以從子類調(diào)用超類的構(gòu)造函數(shù)。]
來自O(shè)racle官方文檔https://docs.oracle.com/javas...

class Parent{
    Parent() {
        System.out.println("調(diào)用父類構(gòu)造方法!");
    }
    private static void staticParent() {
        System.out.println("調(diào)用父類靜態(tài)方法");
    }
    private final  void finalParent() {
        System.out.println("調(diào)用父類final方法");
    }
    private void printParent(){
        System.out.println("調(diào)用父類私有方法");
    }
}
class Child extends Parent {
    public void printChild(){
        System.out.println("調(diào)用子類公有方法");
    }
}
public class Test {
    public static void main(String[] args) throws Exception {
        //獲取子類
        Class clazz = Class.forName("work.litao.Child");
        //得到父類
        Class superClass = clazz.getSuperclass();
        //得到父類非繼承的所以方法
        Method[] methods = superClass.getDeclaredMethods();
        //設(shè)置私有方法可以被訪問
        AccessibleObject.setAccessible(methods,true);
        for (Method m:methods) {
            System.out.println();
            System.out.println("子類調(diào)用方法"+m.getName()+"()的調(diào)用結(jié)果:" );
            m.invoke(new Child());
        }

    }
}

運行結(jié)果：