Class.isAssignableFrom
3194 ワード
isAssignableFromは、あるクラスClass 1と別のクラスClass 2が同じか、または別のクラスかを判断するためのスーパークラスまたはインタフェースです.通常呼び出し形式はClass 1である.isAssignableFrom(Class 2)呼び出し者とパラメータはjavaです.lang.Classタイプ.
簡単な例
public class A {
}
public class B extends A {
}
テスト
/**Class.isAssignableFrom
* isAssignableFrom Class1 Class2 。
* @author
*
*/
public class Test2 {
public static void main(String[] args) {
A a = new A();
B b = new B();
A ba = new B();
System.out.println(a.getClass());
System.out.println(b.getClass());
System.out.println(ba.getClass());
System.out.println("=====================");
System.out.println(a.getClass().isAssignableFrom(b.getClass()));//true
System.out.println(b.getClass().isAssignableFrom(a.getClass()));//false
System.out.println("=====================");
System.out.println(ba.getClass().isAssignableFrom(a.getClass()));//false
System.out.println(a.getClass().isAssignableFrom(ba.getClass()));//true
System.out.println("=====================");
System.out.println(ba.getClass().isAssignableFrom(b.getClass()));//true
System.out.println(b.getClass().isAssignableFrom(ba.getClass()));//true
System.out.println("1-------------");
System.out.println(A.class.isAssignableFrom(a.getClass()));//true
System.out.println(B.class.isAssignableFrom(b.getClass()));//true
System.out.println(A.class.isAssignableFrom(b.getClass()));//true
System.out.println(B.class.isAssignableFrom(a.getClass()));//false
System.out.println(A.class.isAssignableFrom(ba.getClass()));//true
System.out.println(B.class.isAssignableFrom(ba.getClass()));//true
System.out.println("2-------------");
System.out.println(a.getClass().isAssignableFrom(A.class));//true
System.out.println(b.getClass().isAssignableFrom(B.class));//true
System.out.println(a.getClass().isAssignableFrom(B.class));//true
System.out.println(b.getClass().isAssignableFrom(A.class));//false
System.out.println(ba.getClass().isAssignableFrom(A.class));//false
System.out.println(ba.getClass().isAssignableFrom(B.class));//true
System.out.println("3-------------");
System.out.println(Object.class.isAssignableFrom(b.getClass()));
System.out.println(Object.class.isAssignableFrom("abc".getClass()));
System.out.println("4-------------");
System.out.println("a".getClass().isAssignableFrom(Object.class));//string false
System.out.println("abc".getClass().isAssignableFrom(Object.class));//string false
}
結果
class com.ghgcn.test01.A
class com.ghgcn.test01.B
class com.ghgcn.test01.B
=====================
true
false
=====================
false
true
=====================
true
true
1-------------
true
true
true
false
true
true
2-------------
true
true
true
false
false
true
3-------------
true
true
4-------------
false
false