《Java编程思想》读书笔记(12)
以前学c语言时,总是在自己写的函数里为程序的各种运行情况设置一个返回标志值,返回值可以是1,0等标志值,来根据这些标志值来判断程序是否正常运行,但代码多了就总是搞不清楚这些标志值之间的区别,因此代码就变得很难读了。而java用“异常处理”很好地解决了这个恼火的问题。
异常处理理论上划分为两种:中止模型(temination),也就是java和c++采用的模型,它假定错误十分严重,因此无法回到错误的地方,只能抛出异常。还有一种就是“继续(resumption),它认为异常处理程序应该能对当前的运行环境进行修复,然后尝试上次出错了的方法。也就是说处理完异常后,希望能够继续运行当前指令。但这种模型的”耦合性“太大。
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Java异常处理中存在着一个错误,如果用如下方式去使用的话就会出错:
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在覆写一个方法时,只能抛出这个方法在基类中的版本所声明的异常,这样就可以实现多态性。
作者:洞庭散人
出处:http://phinecos.cnblogs.com/
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posted on 2006-06-14 13:11 Phinecos(洞庭散人) 阅读(432) 评论(0) 编辑 收藏 举报