字符串字面量

女爷i 2022-12-06 15:29 225阅读 0赞

一个

String literal is a sequence of characters used by Java programmers to populate

String objects or display text to a user. The characters could be letters, numbers or symbols and are enclosed within two quotation marks. For exam

"I live at 22b Baker Street!"

is a

是一个

String lite

Although in your [Java][] code you will be writing the text within the quotes, the Java compiler will interpret the characters as [Unicode code points][].

尽管在[Java][]代码中您将在引号内编写文本，但是Java编译器会将字符解释为[Unicode代码点][Unicode code points] 。

Unicode is a standard that assigns all letters, numbers, and symbols a unique numerical code. This means that every computer will display the same character for each numerical code. This means that if you know the number values you can actually write

Unicode是为所有字母，数字和符号分配唯一数字代码的标准。 这意味着每台计算机将为每个数字显示相同的字符。 这意味着，如果您知道数字值，则可以实际编写

String literals using Unicode val

"\u0049\u0020\u006C\u0069\u0076\u0065\u0020\u0061\u0074\u0020\u0032\u0032\u0042\u0020\u0042\u0061\u006B\u0065\u0072\u0020\u0053\u0074\u0072\u0065\u0065\u0074\u0021"

represents the same

代表相同

String value as "I live at 22b Baker Street!" but obviously it's not as nice to wr

Unicode and normal text characters can also be mixed. This is useful for characters you might not know how to type. For example, a character with an umlaut (e.g., Ä, Ö) as in "Thomas Müller plays for Germany." would be:

Unicode和普通文本字符也可以混合使用。 这对于您可能不知道如何键入的字符很有用。 例如，“托马斯·穆勒(ThomasMüller)为德国效力”中的一个带有变音符号的字符(例如Ä，Ö)。 将是：

"Thomas M\u00FCller plays for Germany."

To assign a

分配一个

String object a value just use a

String lite

String text = "So does Dr Watson";

## 转义序列 **(** Escape Sequences **)** ##

There are certain characters that you might want to include into a

您可能需要将某些字符包含在

String literal which need to be identified to the compiler. Otherwise, it might get confused and not know what the

String value is supposed to be. For example, imagine you want to put a quotation mark within a

String lite

"So my friend said, "It's how big?""

This would confuse the compiler because it expects all

这会使编译器感到困惑，因为它期望所有

String literals to begin and end with a quotation mark. To get around this we can use what is known as an escape sequence - these are characters which are preceded by a backslash (in fact you've already seen several if you look back at the Unicode character codes). For example, a quotation mark has the escape seque

So the

所以

String literal above would be writ

"So my friend said, \"It's how big?\""

Now the compiler will come to the backslash and know the quotation mark is part of the

现在，编译器将使用反斜杠，并且知道引号是

String literal instead of its end point. If you're thinking ahead you're probably wondering but what if I want to have a backslash in my

String literal? Well, that's easy - its escape sequence follows the same pattern - a backslash before the charac

Some of the escape sequences available don't actually print a character to the screen. There are times when you might want to display some text split by a newline. For example:

某些可用的转义序列实际上并未在屏幕上打印字符。 有时您可能需要显示一些用换行符分隔的文本。 例如：

The first line.

The second line.

This can be done by using the escape sequence for the newline character:

这可以通过对换行符使用转义序列来完成：

"The first line.\nThe second line."

It's a useful way to put a little bit of formatting into one

这是将一些格式化内容整合为一个有用的方法

Sting lite

There are several useful escape sequences worth knowing:

有几个有用的转义序列值得了解：

*      \t is for inserting tabs into the literal
 *      \b inserts a backspace
 *      \n inserts a newline
 *      \r inserts a carriage return
 *      \' inserts a single quotation mark
 *      \" inserts a double quotation mark
 *      \\ inserts a backslash

Example Java code can be found in the [Fun With Strings Example Code][].

可以在“ [字符串有趣示例代码”中][Fun With Strings Example Code]找到Java [示例代码][Fun With Strings Example Code] 。

> 翻译自: [https://www.thoughtco.com/the-string-literal-2034316][https_www.thoughtco.com_the-string-literal-2034316]

[Java]: https://www.thoughtco.com/what-is-java-2034117
[Unicode code points]: https://www.thoughtco.com/what-is-unicode-2034272
[Fun With Strings Example Code]: https://www.thoughtco.com/fun-with-strings-example-code-2034322
[https_www.thoughtco.com_the-string-literal-2034316]: https://www.thoughtco.com/the-string-literal-2034316