How do I replace a character in a string in Java

Question

Using Java  I want to go through the lines of a text and replace all ampersand symbols   amp   with the XML entity reference  amp amp    I scan the lines of the text and then each word in the text with the Scanner class  Then I use the CharacterIterator to iterate over each characters of the word   However  how can I replace the character   First  Strings are immutable objects   Second  I want to replace a character   amp   with several characters amp amp      How should I approach this   CharacterIterator it   new StringCharacterIterator token   for char ch   it first    ch    CharacterIterator DONE  ch   it next             if ch      amp

User · Answer

If you re using Spring you can simply call HtmlUtils htmlEscape String input  which will handle the   amp   to   amp   translation

User · Answer

Just create a string that contains all of the data in question and then use String replaceAll   like below   String result   yourString replaceAll   amp      amp amp

User · Answer

StringBuilder s   new StringBuilder token length      CharacterIterator it   new StringCharacterIterator token   for  char ch   it first    ch    CharacterIterator DONE  ch   it next          switch  ch            case   amp                s append   amp amp                 break          case   lt                s append   amp lt                 break          case   gt                s append   amp gt                 break          default              s append ch               break           token   s toString

User · Answer

Try using String replace   or String replaceAll   instead   String my new str   my str replace   amp      amp amp        Both replace all occurrences  replaceAll allows use of regex

User · Answer

You can use stream and flatMap to map  amp  to  amp amp       String str    begin amp end       String newString   str chars            flatMap ch - gt   ch      amp        amp amp   chars     IntStream of ch            collect StringBuilder  new  StringBuilder  appendCodePoint  StringBuilder  append           toString

User · Answer

Try this code You can replace any character with another given character  Here I tried to replace the letter  a  with  -  character for the give string  abcdeaa   OutPut --  bcdef        public class Replace        public static void replaceChar String str String target           String result   str replaceAll target                System out println result              public static void main String   args            replaceChar  abcdefaa   a

User · Answer

The simple answer is   token   token replace   amp      amp amp       Despite the name as compared to replaceAll  replace does do a replaceAll  it just doesn t use a regular expression  which seems to be in order here  both from a performance and a good practice perspective - don t use regular expressions by accident as they have special character requirements which you won t be paying attention to    Sean Bright s answer is probably as good as is worth thinking about from a performance perspective absent some further target requirement on performance and performance testing  if you already know this code is a hot spot for performance  if that is where your question is coming from  It certainly doesn t deserve the downvotes  Just use StringBuilder instead of StringBuffer unless you need the synchronization   That being said  there is a somewhat deeper potential problem here  Escaping characters is a known problem which lots of libraries out there address  You may want to consider wrapping the data in a CDATA section in the XML  or you may prefer to use an XML library  including the one that comes with the JDK now  to actually generate the XML properly  so that it will handle the encoding    Apache also has an escaping library as part of Commons Lang

User · Answer

String taskLatLng   task getTask latlng   replaceAll            replaceAll           replaceAll  lat lng        trim

User · Answer

You may also want to check to make sure your not replacing an occurrence that has already been replaced  You can use a regular expression with negative lookahead to do this   For example    String str    sdasdasa amp amp adas amp dasdasa     str   str replaceAll   amp    amp       amp amp       This would result in the string  sdasdasa amp amp adas amp amp dasdasa    The regex pattern   amp    amp    basically says  Match any occurrence of   amp   that is not followed by  amp

User · Answer

I think this will work  you don t have to replace on the even  it s just an example     public void emphasize String phrase  char ch                char phraseArray     phrase toCharArray             for int i 0  i lt  phrase length    i                          if i 2  0    even number                               String value   Character toString phraseArray i                     value   value replace value                        phraseArray i    value charAt 0

User · Answer

Escaping strings can be tricky - especially if you want to take unicode into account  I suppose XML is one of the simpler formats languages to escape but still  I would recommend taking a look at the StringEscapeUtils class in Apache Commons Lang  and its handy escapeXml method

[java] How do I replace a character in a string in Java?

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