CODEWITHSUNDEEP
java
Amira
Amira

Reputation: 3270

Insert a character in a String before a specific character

I need to change a string as follow : Adding a "\" before any founded special character here an example : If the string = ${Name} the result should be ===> \${NAME}

I wrote this : 

private static String getFormattedString(String variable) {
  char [] specialCharacters = {'.', '\\', '+', '*', '?', '[', '^', ']', '$', '(', ')' ,'{' ,'}', '=', '!', '<', '>', '|', ':', '-'};
  String old = variable;
  String formatted = "";
  int i=0;
  while(i<old.length()) {
    for (int j=0;j<specialCharacters.length;j++) {

if (old.charAt(i) == specialCharacters[j]) {
  formatted+=old.substring(0, i)+"\\"+old.substring(i, i+1);
  old=variable.substring(i+1,variable.length());
  break;
} 
  }
  i++;
}
return formatted;
}

But i'm getting a wrong result : 

 Formatted String : ++++> \${NAME\}

I'm really confused, any idea will be appreciated.

Upvotes: 1

Views: 243

Answers (4)

fge
fge

Reputation: 121712

Try this:

private static final List<Character> SPECIAL = Arrays.asList('.', /* etc */);

public static String escape(final String input)
{
    final StringBuilder sb = new StringBuilder(input.length());
    final CharBuffer buf = CharBuffer.wrap(input);
    char c;

    while (buf.hasRemaining()) {
        c = buf.get();
        if (SPECIAL.contains(c))
            sb.append('\\');
        sb.append(c);
    }

    return sb.toString();
}

(CharBuffer is underused, even though it is the best way to iterate over a String's characters!)

If you use Guava 15+, you can also write your own CharEscaper; like everything Guava, it works wonderfully well!

Upvotes: 4

Pulah Nandha
Pulah Nandha

Reputation: 774

Try to use replaceAll function 

private static String getFormattedString(String variable) {
  //No need this.
  // char [] specialCharacters = {'.', '\\', '+', '*', '?', '[', '^', ']', '$', '(', ')' ,'{' ,'}', '=', '!', '<', '>', '|', ':', '-'};
  variable = variable.replaceAll(".","\\."); //same for all.
  variable = variable.replaceAll("+","\\+");.
  variable = variable.replaceAll("*","\\*");
return formatted;
}

Upvotes: -2

Rakesh KR
Rakesh KR

Reputation: 6527

Try with String.replaceAll()

String strgg  = "${Name}";
System.out.println(strgg.replaceAll("\\$", "\\\\\\$"));

Output:

\${Name}

Upvotes: 0

Maciej Dobrowolski
Maciej Dobrowolski

Reputation: 12122

If you just want to escape any special characters, try using StringEscapeUtils from Apache Commons:

import org.apache.commons.lang.StringEscapeUtils;
(...)
    String result = StringEscapeUtils.escapeJava(variable);

Upvotes: 1

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