Question

I’m looking for a way to convert a string that contains a character escape sequence into the represented character.

So, for instance, I want to parse the string \" (which has two characters, a backslash and a double-quote) into the char ". So, an array of chars into one char.

So something that might do something like this and vice versa:

package test;
public class Test {
    private static char parseChar(String string) {
        char c = 0;
        if ("\\n".equals(string)) {
            c = '\n';
        }else if ("\\t".equals(string)) {
            c = '\t';
        }else if ("\\r".equals(string)) {
            c = '\r';
        }else if ("\\f".equals(string)) {
            c = '\f';
        }else if ("\\b".equals(string)) {
            c = '\b';
        }else if ("\\\'".equals(string)) {
            c = '\'';
        }else if ("\\\"".equals(string)) {
            c = '\"';
        }else if ("\\\\".equals(string)) {
            c = '\\';
        }
        return c;
    }
    public static void main(String[] args) {
        for (String arg : args) {
            System.out.println(arg + " : " + (int)parseChar(arg) + " : " + parseChar(arg) + ";");
        }
    }
}

I could not believe there is nothing in java.lang or other that can provide me with good (maybe native) code for this because I feel the above code might be incomplete and not parse every problematic (escapable?) character, because well I’m a noob.
I want a tool that can do the same thing as the String constructor :

String st = "\"";
char ch = st.charAt(0);

ch output : “;

Thank you for reading this, I am sorry if not clear I will check regularly and correct if asked.

PS:

When I run the above code:

java -classpath ~/workspace/MacroRecorder/bin/ test.Test \\n \\t \\f \\r \\b \\\’ \\\” \\\\;

…it outputs

\n : 10 : 
;
\t : 9 :    ;
\f : 12 : 
          ;
;r : 13 : 
\b : 8 :;
\' : 39 : ';
\" : 34 : ";
\\ : 92 : \;

But in Eclipse, the output is completely different with the same parameters especially the ” is very messy.

Answer 1

Apache Commons to the rescue with StringEscapeUtils, you want the unescapeJava method I think: http://commons.apache.org/lang/api-2.4/org/apache/commons/lang/StringEscapeUtils.html#unescapeJava(java.lang.String)