我是一名Java程序员,刚进入企业界。最近我用Groovy和Java开发了一个应用程序。在我编写的所有代码中,都使用了相当多的静态元素。高级技术人员要求我减少使用的静态数据的数量。我在谷歌上搜索过相同的内容,我发现许多程序员都相当反对使用静态变量。

我发现静态变量使用起来更方便。而且我假定它们也是有效的(如果我错了请纠正我),因为如果我必须在一个类中对一个函数进行10,000次调用,我将很高兴使方法静态,并在其上使用直接的class . methodcall(),而不是用10,000个类实例使内存混乱,对吗?

此外,静态减少了对代码其他部分的相互依赖。他们可以作为完美的国家持有者。除此之外,我还发现一些语言(如Smalltalk和Scala)广泛地实现了静态。那么为什么程序员普遍反对静态(尤其是在Java世界中)呢?

PS:如果我对静态数据的假设是错误的,请纠正我。


当前回答

我认为过度使用全局变量和静态关键字也会导致应用程序中实例的某些点的内存泄漏

其他回答

假设您有一个拥有许多用户的应用程序,并且您已经定义了一个静态函数,该函数将状态保存在一个静态变量中,那么每个用户都将修改其他用户的状态。

以上所有答案都说明了为什么静态方法很糟糕。它们是邪恶的原因是因为它给人一种错误的印象,即你在编写面向对象的代码,而事实上你并不是。 这简直是邪恶。

这里有很多很好的答案,

记忆: 静态变量只要类加载器存在(通常直到VM死亡)就存在,但这只是在大块对象/引用存储为静态的情况下。

模块化: 考虑IOC、依赖注入、代理等概念。所有这些都完全反对紧密耦合/静态实现。

其他缺点:线程安全性,可测试性

静态变量本身并没有什么问题。只是Java语法有问题。每个Java类实际上定义了两个结构——一个封装静态变量的单例对象和一个实例。在同一个源代码块中定义这两种代码是非常糟糕的,会导致代码难以阅读。Scala做得很好。

在你的文章中有两个主要问题。

First, about static variables. Static variables are completelly unnecesary and it's use can be avoided easily. In OOP languajes in general, and in Java particularlly, function parameters are pased by reference, this is to say, if you pass an object to a funciont, you are passing a pointer to the object, so you dont need to define static variables since you can pass a pointer to the object to any scope that needs this information. Even if this implies that yo will fill your memory with pointers, this will not necesary represent a poor performance because actual memory pagging systems are optimized to handle with this, and they will maintain in memory the pages referenced by the pointers you passed to the new scope; usage of static variables may cause the system to load the memory page where they are stored when they need to be accessed (this will happen if the page has not been accesed in a long time). A good practice is to put all that static stuf together in some little "configuration clases", this will ensure the system puts it all in the same memory page.

Second, about static methods. Static methods are not so bad, but they can quickly reduce performance. For example, think about a method that compares two objects of a class and returns a value indicating which of the objects is bigger (tipical comparison method) this method can be static or not, but when invoking it the non static form will be more eficient since it will have to solve only two references (one for each object) face to the three references that will have to solve the static version of the same method (one for the class plus two, one for each object). But as I say, this is not so bad, if we take a look at the Math class, we can find a lot of math functions defined as static methods. This is really more eficient than putting all these methods in the class defining the numbers, because most of them are rarelly used and including all of them in the number class will cause the class to be very complex and consume a lot of resources unnecesarilly.

总之:在处理静态或非静态方法时,避免使用静态变量,并找到正确的性能平衡。

PS:抱歉我的英语不好。