TA的每日心情 | 开心 2021-3-12 23:18 |
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签到天数: 2 天 [LV.1]初来乍到
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- /**
- * instanceof 用于检测对象的类型。
- * (1)类的对象与类作instance of操作,结果为true
- * (2)子类对象与父类作instance of操作,结果为true。
- * 因此,所有对象与Object作instance of操作,结果都为true。
- * (3)其他情况下,结果都为false。
- */
- public class InstanceOf {
-
- // 父类
- static class ClassA {
- }
- // 子类
- static class ClassB extends ClassA{
- }
- public static void main(String[] args) {
- ClassA a = new ClassA();
- ClassB b = new ClassB();
- // 检测对象a,b是否为ClassA类型
- if (a instanceof ClassA){
- System.out.println("Object a is a ClassA Object!");
- } else {
- System.out.println("Object a is not a ClassA Object!");
- }
- if (b instanceof ClassA){
- System.out.println("Object b is a ClassA Object!");
- } else {
- System.out.println("Object b is not a ClassA Object!");
- }
-
- // 检测对象a,b是否为ClassB类型
- if (a instanceof ClassB){
- System.out.println("Object a is a ClassB Object!");
- } else {
- System.out.println("Object a is not a ClassB Object!");
- }
- if (b instanceof ClassB){
- System.out.println("Object b is a ClassB Object!");
- } else {
- System.out.println("Object b is not a ClassB Object!");
- }
- }
- }
- 运行结果:
- C:java>java InstanceOf
- Object a is a ClassA Object!
- Object b is a ClassA Object!
- Object a is not a ClassB Object!
- Object b is a ClassB Object!
复制代码
源码下载:http://file.javaxxz.com/2014/10/2/071734672.zip |
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