得到方法调用者和java中的位操作符
获取方法的调用者
如果你写了一个超级复杂超级大的项目,在项目后期调试修改的时候,突然想知道到底是哪些类调用了ImportantClass中的Important方法,你会怎么做呢?
首先,你可能说:我用不到!如果这样的话,到这里你就可以return了。
做法一:最常规有效的做法,使用IDE的全目录全文搜索方法名。当然这样是最有效快速的。但是如果有很多别的类中也定义了Important方法,你就会得到很多垃圾搜索结果。同时你只能搜索到目录下的结果,而对于运行时调用Important方法的地方你就无所适从了。
做法二:这就是我要说的,编写程序,获取方法调用者。最直观的例子就是我们每天都在用了log4j。在执行log.debug或者别的输出日至的操作的时候,它都会按照设定的格式输出类名、方法名、甚至所在的行数。如果我们在Important方法中插入这么一段,就可以知道到底是谁在运行期调用了Important方法了。
在demo程序中有详细的注释和一个完整的例子。我们知道把那段代码拷贝到关系的程序中,修改一下fullClassName就可以了。
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java中的位操作符
因为不常用,所以经常忘记。索性抽时间总结一下,备忘。
对于java这种语言来说,位操作符比较少用到
&:按位与。
|:按位或。
^:按位异或。
~:按位取反。
<<:左移,高位插0,否则插1;
>>:右移,高位插0,否则插1;
>>>:无符号右移,无论正负,高位插0
令人奇怪的是java似乎好像大概说不定没有同或操作符,why?莫非是想让我们把~和^组合一下代替同或操作符?
http://www.matrix.org.cn/resource/article/43/43978_Java_Bitfields_Bitboards.html 这篇文章讲的是相当不错,看了个开头,感觉很有水平,不过篇幅太长,不宜上班时阅读,留作备忘以后慢慢读之。