当是'StringBuilder`是pferred而不是附加`String`到`String` $ P $？ [英] When is `StringBuilder` is preferred instead appending `String` to `String`?

问题描述

下面是两种方法如何追加字符串：

Below are two ways how to append String:

String firstString = "text_0";
String secondString = "text_1";
String resultString = firstString + secondString;

StringBuilder sb = new StringBuilder();
sb.append(firstString).append(secondString);
String resultString = sb.toString();

我的问题是 - 当是更有效的使用的StringBuilder ？比方说，有10个字符串，我需要创建其中之一。

My question is - when is more effective to use StringBuilder? Let's say there are 10 strings, and I need to create one of them.

推荐答案

由于StringBuilder的可以追加字符串而不是将每次创建一个新的对象两个字符串。即使您使用+ =运算符与字符串创建一个新的对象。一旦你试图连接字符串的大量这种优势只会越来越相关。如果还consiedered可读性更强一点。

Because StringBuilder can "append" a string instead of concatenating two strings each time creating a new object. Even if you use += operator with Strings a new object is created. This advantage will only become relevant once you try to concatenate a great number of strings. If is also consiedered a bit more readable.

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