为什么String是班级? [英] Why is String a class?

问题描述

如果可以仅使用它启动

String s = "Hello";

那为什么要上课?参数在哪里?

then why is it a class? Where's the parameters?

推荐答案

鉴于 String 是一个如此有用且经常使用的类，它具有特殊的语法(通过字符串文字表示形式:文本在" 内)来创建其实例，但从语义上讲，这两个是等效的:

Given that String is such a useful and frequently used class, it has a special syntax (via a string literal representation: the text inside "") for creating its instances, but semantically these two are equivalent:

String s = "Hello"; // just syntactic sugar
String s = new String("Hello");

在引擎盖后面，两种形式都是不是 100％等效，因为使用" 的语法会尝试重用Java字符串池中的字符串，而使用的显式实例化> new String(")将始终创建一个新对象.

Behind the hood both forms are not 100% equivalent, as the syntax using "" tries to reuse strings from Java's string pool, whereas the explicit instantiation with new String("") will always create a new object.

但请不要误解，这两种语法都会产生对对象实例的引用，字符串在Java中不被视为原始类型，并且像其他任何类型一样，都是类的实例.

But make no mistake, either syntax will produce a reference to an object instance, strings are not considered primitive types in Java and are instances of a class, like any other.

这篇关于为什么String是班级?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！