addcommas.java

java实现正则表达式的代码

/*
 * $Id: addCommas.java,v 1.7 2003/11/07 20:16:23 dfs Exp $
 *
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 * The Apache Software License, Version 1.1
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 * reserved.
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 * modification, are permitted provided that the following conditions
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package examples;

import org.apache.oro.text.perl.*;

/**
 *
 * This is an example program based on a short example from the Camel book.
 * It demonstrates substitutions by adding commas to a the string
 * representation of an integer.
 *
 * @version @version@
 */
public final class addCommas {

  /**
   * This program takes a string as an argument and adds commas to all the
   * integers in the string exceeding 3 digits in length, placing each comma
   * three digits apart.
   */
  public static final void main(String args[]) {
    String number;
    Perl5Util perl;

    if(args.length < 1) {
      System.err.println("Usage: addCommas integer");
      System.exit(1);
    }

    number = args[0];
    perl = new Perl5Util();

    while(perl.match("/[+-]?\\d*\\d{4}/", number))
      number = perl.substitute("s/([+-]?\\d*\\d)(\\d{3})/$1,$2/", number);

    System.out.println(number);
  }

}