java中parseInt()和valueOf()之间的区别? [英] Different between parseInt() and valueOf() in java?

问题描述

parseInt()与valueOf()有何不同?

它们似乎对我做着完全相同的事情(parseFloat()，parseDouble()，parseLong()等也是如此，它们与Long.valueOf(string)有何不同?

They appear to do exactly the same thing to me (also goes for parseFloat(), parseDouble(), parseLong() etc, how are they different from Long.valueOf(string) ?

还有，其中哪一种是更可取的，并且习惯上使用得更多?

Also, which one of these is preferable and used more often by convention?

推荐答案

Well, the API for Integer.valueOf(String) does indeed say that the String is interpreted exactly as if it were given to Integer.parseInt(String). However, valueOf(String) returns a new Integer() object whereas parseInt(String) returns a primitive int.

如果您想享受 Integer.valueOf(int) ，您也可以使用这种令人讨厌的方法:

If you want to enjoy the potential caching benefits of Integer.valueOf(int), you could also use this eyesore:

Integer k = Integer.valueOf(Integer.parseInt("123"))

现在，如果想要的是对象而不是原始对象，则使用valueOf(String)可能比用parseInt(String)制作新对象更具吸引力，因为前者在Integer，Long中始终存在，Double等

Now, if what you want is the object and not the primitive, then using valueOf(String) may be more attractive than making a new object out of parseInt(String) because the former is consistently present across Integer, Long, Double, etc.

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