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copied!<p>I use the following two methods, toPrintable to convert the original string to a printable string, fromPrintable to convert it back.</p> <p>I included the percent sign in the conversion because sometimes I may want to use the converted string as a part of a format string and this prevents the original percent signs getting confused with the formatting percent signs.</p> <pre><code>/** * Converts a string containing control characters to a printable string. * Control characters are replaced by \hh, were hh is the hexadecimal * representation. The backslash and percent sign are also converted to * hexadecimal. * * @param raw * The input string to be converted. * * @return a string representing this instance. */ public static String toPrintable(final String raw) { final StringBuilder sb = new StringBuilder(); if (raw == null) { return ""; } for (final char c : raw.toCharArray()) { if ((c <= 31) || (c == 127) || (c == '\\') || (c == '%')) { sb.append(String.format("\\%02X", (int) c)); } else { sb.append(c); } } /* * If the last character is a space, convert it to hexadecimal, to avoid * loosing it. */ if (raw.endsWith(" ")) { sb.setLength(sb.length() - 1); sb.append("\\20"); } return sb.toString(); } /** * Converts a string containing coded control characters to the original * string. Control characters are represented by \hh, were hh is the * hexadecimal representation. The backslash is also represented as * hexadecimal. * * @param t * The converted string to be restored. * @return The original string. */ public static String fromPrintable(final String t) { final StringBuilder sb = new StringBuilder(); final int tLength = t.length(); boolean error = false; for (int i = 0; i < tLength; i++) { if (t.charAt(i) == '\\') { if ((i + 1) < tLength) { if (t.charAt(i + 1) == '\\') { sb.append(t.charAt(i++)); } else { if (i < (tLength - 2)) { final int v1 = validHexDigits.indexOf(t .charAt(i + 1)); final int v2 = validHexDigits.indexOf(t .charAt(i + 2)); i += 2; if ((v1 < 0) || (v2 < 0)) { error = true; } else { final char cc = (char) ((validHexValues[v1] << 4) + validHexValues[v2]); sb.append(cc); } } else { error = true; } } } else { error = true; } } else { sb.append(t.charAt(i)); } } if (error) { log.warn("fromPrintable: Invalid input [%s]", t); } return sb.toString(); } </code></pre>

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