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Java Cookbook by Ian F. Darwin

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Entering Non-Printable Characters

Problem

You need to put non-printable characters into strings.

Solution

Use the backslash character and one of the Java string escapes.

Discussion

The Java string escapes are listed in Table 3-1.

Table 3-1. String escapes

To get:

Use this:

Notes

Tab

\t

 

Linefeed (Unix newline)

\n

See System.getProperty("line.separator"), which gives you the platform’s line end.

Carriage return

\r

 

Form feed

\f

 

Backspace

\b

 

Single quote

\'

 

Double quote

\"

 

Unicode character

\u NNNN

Four hexadecimal digits (no \x as in C/C++). See http://www.unicode.org for codes.

Octal(!) character

\ NNN

Who uses octal (base 8) these days?

Backslash

\\

 

Here is a code example that shows most of these in action:

// StringEscapes.java
System.out.println("Java Strings in action:");
// System.out.println("An alarm or alert: \a");    // not supported
System.out.println("An alarm entered in Octal: \007");
System.out.println("A tab key: \t(what comes after)");
System.out.println("A newline: \n(what comes after)");
System.out.println("A UniCode character: \u0207");
System.out.println("A backslash character: \\");

If you have a lot of non-ASCII characters to enter, you may wish to consider using Java’s input methods, discussed briefly in the JDK online documentation.

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