转[收集java的常用函数代码]

package net.java2000.tools;
/**
* Title:        Java Bean 工具
* Description:
* Copyright:    Copyright (c) 2001
* Company:      JAVA世纪网 
* @author 赵学庆
* @version 1.0
*/
import java.util.*;
import java.util.regex.Pattern;
public class StrTools {
  /**
   * 分割字符串
   *
   * @param str String 原始字符串
   * @param splitsign String 分隔符
   * @return String[] 分割后的字符串数组
   */
  @SuppressWarnings("unchecked")
  public static String[] split(String str, String splitsign) {
    int index;
    if (str == null || splitsign == null)
      return null;
    ArrayList al = new ArrayList();
    while ((index = str.indexOf(splitsign)) != -1) {
      al.add(str.substring(0, index));
      str = str.substring(index + splitsign.length());
    }
    al.add(str);
    return (String[]) al.toArray(new String[0]);
  }
  /**
   * 替换字符串
   *
   * @param from String 原始字符串
   * @param to String 目标字符串
   * @param source String 母字符串
   * @return String 替换后的字符串
   */
  public static String replace(String from, String to, String source) {
    if (source == null || from == null || to == null)
      return null;
    StringBuffer bf = new StringBuffer("");
    int index = -1;
    while ((index = source.indexOf(from)) != -1) {
      bf.append(source.substring(0, index) + to);
      source = source.substring(index + from.length());