Removing whitespace from strings in Java

Question

I have a string like this:

mysz = \"name=john age=13 year=2001\";

I want to remove the whitespaces in the string. I tried trim()

Answer 1

Use apache string util class is better to avoid NullPointerException

org.apache.commons.lang3.StringUtils.replace("abc def ", " ", "")

Output

abcdef

Answer 2

Separate each group of text into its own substring and then concatenate those substrings:

public Address(String street, String city, String state, String zip ) {
    this.street = street;
    this.city = city;
    // Now checking to make sure that state has no spaces...
    int position = state.indexOf(" ");
    if(position >=0) {
        //now putting state back together if it has spaces...
        state = state.substring(0, position) + state.substring(position + 1);  
    }
}

Answer 3

Using Pattern And Matcher it is more Dynamic.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RemovingSpace {

    /**
     * @param args
     * Removing Space Using Matcher
     */
    public static void main(String[] args) {
        String str= "jld fdkjg jfdg ";
        String pattern="[\\s]";
        String replace="";

        Pattern p= Pattern.compile(pattern);
        Matcher m=p.matcher(str);

        str=m.replaceAll(replace);
        System.out.println(str);    
    }
}

Answer 4

replaceAll("\\s","")

\w = Anything that is a word character

\W = Anything that isn't a word character (including punctuation etc)

\s = Anything that is a space character (including space, tab characters etc)

\S = Anything that isn't a space character (including both letters and numbers, as well as punctuation etc)

(Edit: As pointed out, you need to escape the backslash if you want \s to reach the regex engine, resulting in \\s.)

Answer 5

There are others space char too exists in strings.. So space char we may need to replace from strings.

Ex: NO-BREAK SPACE, THREE-PER-EM SPACE, PUNCTUATION SPACE

Here is the list of space char http://jkorpela.fi/chars/spaces.html

So we need to modify

\u2004 us for THREE-PER-EM SPACE

s.replaceAll("[\u0020\u2004]","")

Answer 6

public static String removeWhiteSpaces(String str){
    String s = "";
    char[] arr = str.toCharArray();
    for (int i = 0; i < arr.length; i++) {
        int temp = arr[i];
        if(temp != 32 && temp != 9) { // 32 ASCII for space and 9 is for Tab
            s += arr[i];
        }
    }
    return s;
}

This might help.