如果一个实例完全属于给定类型,我需要测试.但是,如果子类型被测试为超类型,则似乎instanceof也返回true(情况3).我以前从来不知道这一点,我很惊讶.我在这里做错了吗？我如何准确测试给定类型？
//..
class DataSourceEmailAttachment extends EmailAttachment
//...
EmailAttachment emailAttachment = new EmailAttachment();
DataSourceEmailAttachment emailAttachmentDS = new DataSourceEmailAttachment();
if (emailAttachment instanceof EmailAttachment){
System.out.println(" 1");
}
if (emailAttachment instanceof DataSourceEmailAttachment){
System.out.println(" 2");
}
if (emailAttachmentDS instanceof EmailAttachment){
System.out.println(" 3 ");
}
if (emailAttachmentDS instanceof DataSourceEmailAttachment){
System.out.println(" 4");
}
结果：
1 3 4
我想避免案例3,我只想要“完全匹配”(案例1和4)我该如何测试它们？
解决方法
if( emailAttachment.getClass().equals(EmailAttachment.class) )
