Removes all non-alphanumeric characters from the given String. - Java java.lang

Java examples for java.lang:char

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Description

Removes all non-alphanumeric characters from the given String.

Demo Code


//package com.java2s;

public class Main {
  public static void main(String[] argv) {
    String string = "java2s.com";
    System.out.println(cleanAlphaNumeric(string));
  }/* ww  w  . jav a  2s  . c o m*/

  /**
   * This is just a convenience constant to avoid instantiating a String for
   * comparisons and such
   */
  public static final String EMPTY_STRING = "";

  /**
   * Removes all non-alphanumeric characters from the given String.
   */
  public static String cleanAlphaNumeric(final String string) {
    String process = noNull(string);
    StringBuffer buffer = new StringBuffer(process.length());

    for (int i = 0; i < process.length(); i++) {
      char c = process.charAt(i);

      if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9'))
        buffer.append(c);
    }

    return buffer.toString();
  }

  /**
   * Substitutes a null variable with an empty String.
   */
  public static String noNull(final Object string) {
    if (string == null)
      return EMPTY_STRING;

    // Don't call toString twice.
    String ser = string.toString();

    return ser == null ? EMPTY_STRING : ser;
  }

}

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