Java中的String和StringBuffer有什么区别？ [英] What is the difference between String and StringBuffer in Java?

问题描述

Java中String和StringBuffer有什么区别？

What is the difference between String and StringBuffer in Java?

String的最大大小是什么？

Is there a maximum size for String?

推荐答案

字符串用于处理无法更改的字符串（只读和不可变）。

String is used to manipulate character strings that cannot be changed (read-only and immutable).

StringBuffer 用于表示可以修改的字符。

StringBuffer is used to represent characters that can be modified.

性能方面， StringBuffer 在执行连接时速度更快。这是因为当你连接一个 String 时，你每次都在（内部）创建一个新对象，因为 String 是不可变的。

Performance wise, StringBuffer is faster when performing concatenations. This is because when you concatenate a String, you are creating a new object (internally) every time since String is immutable.

您还可以使用 StringBuilder ，类似于 StringBuffer 除了它没有同步。其中任何一个的最大大小是 Integer.MAX_VALUE （2 ³¹ - 1 = 2,147,483,647）或最大堆大小除以2（参见 Java String有多少个字符？）。
更多信息此处。

You can also use StringBuilder which is similar to StringBuffer except it is not synchronized. The maximum size for either of these is Integer.MAX_VALUE (2³¹ - 1 = 2,147,483,647) or maximum heap size divided by 2 (see How many characters can a Java String have?). More information here.

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