在 Java 中字符文字’n’和’r’之间有什么区别？

在 Java 中，换行符和回车符似乎都表现出同样的效果。

在 Java 中字符文字 \n和 \r之间的实际区别是什么？

请注意，上面询问的是 \n 性格，而不是 BufferedWriter上的 newLine()函数，因此 另一个问题是不相关的。

260620 次浏览
小开

\n is a line feed (LF) character, character code 10. \r is a carriage return (CR) character, character code 13. What they do differs from system to system. On Windows, for instance, lines in text files are terminated using CR followed immediately by LF (e.g., CRLF). On Unix systems and their derivatives, only LF is used. (Macs prior to Mac OS X used CR, but Mac OS X is a *nix derivative and so uses LF.)

In the old days, LF literally did just a line feed on printers (moving down one line without moving where you are horizonally on the page), and CR similarly moved back to the beginning of the line without moving the paper up, hence some systems (like Windows) sending CR (return to the left-hand side) and LF (and feed the paper up).

Because of all this confusion, some output targets will accept multiple line break sequences, so you could see the same effect from either character depending on what you're outputting to.

小开

The difference is not Java-specific, but platform specific. Historically UNIX-like OSes have used \n as newline character, some other deprecated OSes have used \r and Windows OSes have employed \r\n.

小开

It actually depends on what is being used to print the result. Usually, the result is the same, just as you say -

Historically carriage return is supposed to do about what the home button does: return the caret to the start of the line.

\n is supposed to give you a new line but not move the caret.

If you think about old printers, you're pretty much thinking how the original authors of the character sets were thinking. It's a different operation moving the paper feeder and moving the caret. These two characters express that difference.

小开

It depends on which Platform you work. To get the correct result use -

System.getProperty("line.separator")
小开

\n is for unix
\r is for mac (before OS X)
\r\n is for windows format

you can also take System.getProperty("line.separator")

it will give you the appropriate to your OS

小开

When you print a string in console(Eclipse),\n,\r and \r\n have the same effect,all of them will give you a new line;but \n\r(also \n\n,\r\r) will give you two new lines;when you write a string to a file,only \r\n can give you a new line.

小开

The above answers provided are perfect. The LF(\n), CR(\r) and CRLF(\r\n) characters are platform dependent. However, the interpretation for these characters is not only defined by the platforms but also the console that you are using. In Intellij console (Windows), this \r character in this statement System.out.print("Happ\ry"); produces the output y. But, if you use the terminal (Windows), you will get yapp as the output.

小开

On the command line, \r will move the cursor back to the beginning of the current line. To see the difference you must run your code from a command prompt. Eclipse's console show similar output for both the expression. For complete list of escape sequences, click here https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.6


提交答案