/* equals()方法默认的比较两个对象的引用! */ class Child { int num; public Child(int x){ num = x; } //人文的抛出运行时异常的好处是:可以自定义错误信息! /*public boolean equals(Object o) throws ClassCastException{ if(!(o instanceof Child)) throw new ClassCastException("中文提示:类型错误"); Child ch = (Child) o; return num == ch.num ; }*/ /* Exception in thread "main" java.lang.ClassCastException: 中文提示:类型错误 at Child.equals(PC.java:8) at PC.main(PC.java:17) */ public boolean equals(Object o){ Child ch = (Child) o; return num == ch.num ; } /* Exception in thread "main" java.lang.ClassCastException: java.lang.Integer cannot be cast to Child at Child.equals(PC.java:14) at PC.main(PC.java:22) */ } public class PC{ public static void main(String[] args){ Child p1 = new Child(11); if(p1.equals(new Integer(11))) System.out.println("true"); System.out.println("这句话是否执行?");// 如果异常得到了处理, 那么这句话就会执行,否则就不会被执行! } }
java中Object.equals()简单用法,布布扣,bubuko.com
时间: 2024-08-02 02:47:40